docs(ocr): explain why two metrics tests skip fresh_metrics fixture

Sara's cycle-2 S2: clarify the latent (but not actual) cross-test state
risk on the two metrics tests that hit the global REGISTRY instead of
the per-test fresh_metrics fixture. Migrating them would actually break
them — the /metrics endpoint is served by prometheus-fastapi-instrumentator
which binds to the default REGISTRY at app-construction time, and the
http_requests_total assertion only finds counters on that global
registry. Both tests already assert response shape only (status code,
content-type substring, body substrings), not numeric values, so the
shared-registry caveat is documented for future readers rather than
treated as a bug to fix.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/nightly.yml

@@ -79,6 +79,7 @@ jobs:
           IMPORT_HOST_DIR=/srv/familienarchiv-staging/import
           POSTGRES_USER=archiv
           SENTRY_DSN=${{ secrets.SENTRY_DSN }}
+          VITE_SENTRY_DSN=${{ secrets.VITE_SENTRY_DSN }}
           EOF
 
       - name: Verify backend /import:ro mount is wired

backend/src/main/java/org/raddatz/familienarchiv/document/Document.java

@@ -25,11 +25,14 @@ import java.util.UUID;
 @NamedEntityGraph(name = "Document.full", attributeNodes = {
         @NamedAttributeNode("sender"),
         @NamedAttributeNode("receivers"),
-        @NamedAttributeNode("tags")
+        @NamedAttributeNode("tags"),
+        @NamedAttributeNode("trainingLabels")
 })
 @NamedEntityGraph(name = "Document.list", attributeNodes = {
         @NamedAttributeNode("sender"),
-        @NamedAttributeNode("tags")
+        @NamedAttributeNode("receivers"),
+        @NamedAttributeNode("tags"),
+        @NamedAttributeNode("trainingLabels")
 })
 @Entity
 @Table(name = "documents")

backend/src/main/java/org/raddatz/familienarchiv/document/transcription/TranscriptionBlockController.java

@@ -43,7 +43,7 @@ public class TranscriptionBlockController {
 
     @PostMapping
     @ResponseStatus(HttpStatus.CREATED)
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public TranscriptionBlock createBlock(
             @PathVariable UUID documentId,
             @Valid @RequestBody CreateTranscriptionBlockDTO dto,
@@ -53,7 +53,7 @@ public class TranscriptionBlockController {
     }
 
     @PutMapping("/{blockId}")
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public TranscriptionBlock updateBlock(
             @PathVariable UUID documentId,
             @PathVariable UUID blockId,
@@ -65,7 +65,7 @@ public class TranscriptionBlockController {
 
     @DeleteMapping("/{blockId}")
     @ResponseStatus(HttpStatus.NO_CONTENT)
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public void deleteBlock(
             @PathVariable UUID documentId,
             @PathVariable UUID blockId) {
@@ -73,7 +73,7 @@ public class TranscriptionBlockController {
     }
 
     @PutMapping("/reorder")
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public List<TranscriptionBlock> reorderBlocks(
             @PathVariable UUID documentId,
             @RequestBody ReorderTranscriptionBlocksDTO dto) {
@@ -82,7 +82,7 @@ public class TranscriptionBlockController {
     }
 
     @PutMapping("/{blockId}/review")
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public TranscriptionBlock reviewBlock(
             @PathVariable UUID documentId,
             @PathVariable UUID blockId,
@@ -92,7 +92,7 @@ public class TranscriptionBlockController {
     }
 
     @PutMapping("/review-all")
-    @RequirePermission(Permission.WRITE_ALL)
+    @RequirePermission({Permission.ANNOTATE_ALL, Permission.WRITE_ALL})
     public List<TranscriptionBlock> markAllBlocksReviewed(
             @PathVariable UUID documentId,
             Authentication authentication) {

backend/src/main/java/org/raddatz/familienarchiv/importing/MassImportService.java

@@ -56,9 +56,17 @@ public class MassImportService {
 
     public enum State { IDLE, RUNNING, DONE, FAILED }
 
+    public enum SkipReason {
+        INVALID_FILENAME_PATH_TRAVERSAL,
+        INVALID_PDF_SIGNATURE,
+        FILE_READ_ERROR,
+        ALREADY_EXISTS,
+        S3_UPLOAD_FAILED
+    }
+
     public record SkippedFile(
             @Schema(requiredMode = Schema.RequiredMode.REQUIRED) String filename,
-            @Schema(requiredMode = Schema.RequiredMode.REQUIRED) String reason
+            @Schema(requiredMode = Schema.RequiredMode.REQUIRED) SkipReason reason
     ) {}
 
     public record ImportStatus(
@@ -291,6 +299,11 @@ public class MassImportService {
             if (index.isBlank()) continue;
 
             String filename = index.contains(".") ? index : index + ".pdf";
+            if (!isValidImportFilename(filename)) {
+                log.warn("Skipping import row {}: filename rejected — {}", i, filename);
+                skippedFiles.add(new SkippedFile(filename, SkipReason.INVALID_FILENAME_PATH_TRAVERSAL));
+                continue;
+            }
             Optional<File> fileOnDisk = findFileRecursive(filename);
             if (fileOnDisk.isEmpty()) {
                 log.warn("Datei nicht gefunden, importiere nur Metadaten: {}", filename);
@@ -300,17 +313,17 @@ public class MassImportService {
                 try {
                     if (!isPdfMagicBytes(fileOnDisk.get())) {
                         log.warn("Überspringe {}: Datei beginnt nicht mit %PDF-Signatur", filename);
-                        skippedFiles.add(new SkippedFile(filename, "INVALID_PDF_SIGNATURE"));
+                        skippedFiles.add(new SkippedFile(filename, SkipReason.INVALID_PDF_SIGNATURE));
                         continue;
                     }
                 } catch (IOException e) {
                     log.error("Fehler beim Prüfen der Magic-Bytes für {}", filename, e);
-                    skippedFiles.add(new SkippedFile(filename, "FILE_READ_ERROR"));
+                    skippedFiles.add(new SkippedFile(filename, SkipReason.FILE_READ_ERROR));
                     continue;
                 }
             }
 
-            Optional<String> skipReason = importSingleDocument(cells, fileOnDisk, filename, index);
+            Optional<SkipReason> skipReason = importSingleDocument(cells, fileOnDisk, filename, index);
             if (skipReason.isPresent()) {
                 skippedFiles.add(new SkippedFile(filename, skipReason.get()));
             } else {
@@ -320,6 +333,23 @@ public class MassImportService {
         return new ProcessResult(processed, skippedFiles);
     }
 
+    private boolean isValidImportFilename(String filename) {
+        if (filename == null || filename.isBlank()) return false;
+        if (filename.contains("/")) return false;
+        if (filename.contains("\\")) return false;
+        if (filename.contains("∕")) return false;  // U+2215 DIVISION SLASH
+        if (filename.contains("／")) return false;  // U+FF0F FULLWIDTH SOLIDUS
+        if (filename.contains("⧵")) return false;  // U+29F5 REVERSE SOLIDUS OPERATOR
+        if (filename.contains("..")) return false;
+        if (filename.equals(".")) return false;
+        if (filename.contains("\0")) return false;
+        // Paths.get() is safe here on Linux for all inputs that passed the checks above;
+        // it may throw InvalidPathException for OS-specific illegal chars on Windows,
+        // but those are not reachable in production.
+        if (Paths.get(filename).isAbsolute()) return false;
+        return true;
+    }
+
     // package-private: Mockito spy in tests can override to inject IOException
     InputStream openFileStream(File file) throws IOException {
         return new FileInputStream(file);
@@ -342,11 +372,11 @@ public class MassImportService {
      * @return empty Optional on success; an Optional containing the skip reason on failure/skip.
      */
     @Transactional
-    protected Optional<String> importSingleDocument(List<String> cells, Optional<File> file, String originalFilename, String index) {
+    protected Optional<SkipReason> importSingleDocument(List<String> cells, Optional<File> file, String originalFilename, String index) {
         Optional<Document> existing = documentService.findByOriginalFilename(originalFilename);
         if (existing.isPresent() && existing.get().getStatus() != DocumentStatus.PLACEHOLDER) {
             log.info("Dokument {} existiert bereits, überspringe.", originalFilename);
-            return Optional.of("ALREADY_EXISTS");
+            return Optional.of(SkipReason.ALREADY_EXISTS);
         }
 
         String archiveBox    = getCell(cells, colBox);
@@ -382,7 +412,7 @@ public class MassImportService {
                 status = DocumentStatus.UPLOADED;
             } catch (Exception e) {
                 log.error("S3 Upload Fehler für {}", file.get().getName(), e);
-                return Optional.of("S3_UPLOAD_FAILED");
+                return Optional.of(SkipReason.S3_UPLOAD_FAILED);
             }
         }
 
@@ -460,11 +490,18 @@ public class MassImportService {
     }
 
     private Optional<File> findFileRecursive(String filename) {
-        try (Stream<Path> walk = Files.walk(Paths.get(importDir))) {
+        File baseDir = new File(importDir);
-            return walk.filter(p -> !Files.isDirectory(p))
+        try (Stream<Path> walk = Files.walk(baseDir.toPath())) {
+            Optional<Path> match = walk.filter(p -> !Files.isDirectory(p))
                     .filter(p -> p.getFileName().toString().equals(filename))
-                    .map(Path::toFile)
                     .findFirst();
+            if (match.isEmpty()) return Optional.empty();
+            File candidate = match.get().toFile();
+            String baseDirCanonical = baseDir.getCanonicalPath();
+            if (!candidate.getCanonicalPath().startsWith(baseDirCanonical + File.separator)) {
+                throw DomainException.internal(ErrorCode.INTERNAL_ERROR, "Path escape detected: " + candidate);
+            }
+            return Optional.of(candidate);
         } catch (IOException e) {
             return Optional.empty();
         }

backend/src/test/java/org/raddatz/familienarchiv/importing/MassImportServiceTest.java

@@ -154,10 +154,10 @@ class MassImportServiceTest {
                 .build();
         when(documentService.findByOriginalFilename("doc001.pdf")).thenReturn(Optional.of(existing));
 
-        Optional<String> result = service.importSingleDocument(minimalCells("doc001.pdf"), Optional.empty(), "doc001.pdf", "doc001");
+        Optional<MassImportService.SkipReason> result = service.importSingleDocument(minimalCells("doc001.pdf"), Optional.empty(), "doc001.pdf", "doc001");
 
         verify(documentService, never()).save(any());
-        assertThat(result).isPresent().contains("ALREADY_EXISTS");
+        assertThat(result).isPresent().contains(MassImportService.SkipReason.ALREADY_EXISTS);
     }
 
     // ─── importSingleDocument — already-exists guard fires before file I/O ─────
@@ -179,10 +179,10 @@ class MassImportServiceTest {
         byte[] pdfHeader = {0x25, 0x50, 0x44, 0x46, 0x2D}; // %PDF-
         Files.write(physicalFile, pdfHeader);
 
-        Optional<String> result = service.importSingleDocument(
+        Optional<MassImportService.SkipReason> result = service.importSingleDocument(
                 minimalCells("present.pdf"), Optional.of(physicalFile.toFile()), "present.pdf", "present");
 
-        assertThat(result).isPresent().contains("ALREADY_EXISTS");
+        assertThat(result).isPresent().contains(MassImportService.SkipReason.ALREADY_EXISTS);
         verify(s3Client, never()).putObject(any(PutObjectRequest.class), any(RequestBody.class));
         verify(documentService, never()).save(any());
     }
@@ -204,7 +204,7 @@ class MassImportServiceTest {
         assertThat(service.getStatus().skipped()).isEqualTo(1);
         assertThat(service.getStatus().skippedFiles())
                 .extracting(MassImportService.SkippedFile::filename, MassImportService.SkippedFile::reason)
-                .containsExactly(org.assertj.core.groups.Tuple.tuple("upload_fail.pdf", "S3_UPLOAD_FAILED"));
+                .containsExactly(org.assertj.core.groups.Tuple.tuple("upload_fail.pdf", MassImportService.SkipReason.S3_UPLOAD_FAILED));
     }
 
     @Test
@@ -223,7 +223,7 @@ class MassImportServiceTest {
         assertThat(service.getStatus().skipped()).isEqualTo(1);
         assertThat(service.getStatus().skippedFiles())
                 .extracting(MassImportService.SkippedFile::reason)
-                .containsExactly("ALREADY_EXISTS");
+                .containsExactly(MassImportService.SkipReason.ALREADY_EXISTS);
     }
 
     // ─── importSingleDocument — create new document (metadata only) ───────────
@@ -283,11 +283,11 @@ class MassImportServiceTest {
         doThrow(new RuntimeException("S3 error"))
                 .when(s3Client).putObject(any(PutObjectRequest.class), any(RequestBody.class));
 
-        Optional<String> result = service.importSingleDocument(
+        Optional<MassImportService.SkipReason> result = service.importSingleDocument(
                 minimalCells("fail.pdf"), Optional.of(tempFile.toFile()), "fail.pdf", "fail");
 
         verify(documentService, never()).save(any());
-        assertThat(result).isPresent().contains("S3_UPLOAD_FAILED");
+        assertThat(result).isPresent().contains(MassImportService.SkipReason.S3_UPLOAD_FAILED);
     }
 
     // ─── importSingleDocument — sender handling ───────────────────────────────
@@ -438,6 +438,110 @@ class MassImportServiceTest {
         verify(documentService).findByOriginalFilename("doc002.pdf");
     }
 
+    // ─── isValidImportFilename — security regression — do not remove ─────────
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameIsNull() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", (String) null);
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameIsBlank() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "   ");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameContainsForwardSlash() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "etc/passwd");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameContainsBackslash() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "..\\etc\\passwd");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameContainsDotDot() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "doc..evil.pdf");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameIsDotDot() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "..");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameIsAbsolutePath() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "/etc/passwd");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameContainsNullByte() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "file\0.pdf");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsTrue_whenFilenameIsPlainBasename() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "document.pdf");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameContainsUnicodeDivisionSlash() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "foo∕bar.pdf");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameContainsFullwidthSlash() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "foo／bar.pdf");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsFalse_whenFilenameContainsUnicodeReverseSolidus() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "foo⧵bar.pdf");
+        assertThat(result).isFalse();
+    }
+
+    @Test
+    void isValidImportFilename_returnsTrue_whenFilenameHasLeadingDot() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", ".hidden.pdf");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    void isValidImportFilename_returnsTrue_whenFilenameHasSpaces() {
+        boolean result = ReflectionTestUtils.invokeMethod(service, "isValidImportFilename", "Brief an Oma.pdf");
+        assertThat(result).isTrue();
+    }
+
+    @Test
+    void processRows_skipsRowAndContinues_whenFilenameIsPathTraversal() {
+        when(documentService.findByOriginalFilename("legitimate.pdf")).thenReturn(Optional.empty());
+        when(documentService.save(any())).thenAnswer(inv -> inv.getArgument(0));
+
+        List<List<String>> rows = List.of(
+                List.of("header"),
+                minimalCells("../evil"),       // row 1: path traversal — should be skipped
+                minimalCells("legitimate.pdf") // row 2: valid — should be processed
+        );
+        MassImportService.ProcessResult result = ReflectionTestUtils.invokeMethod(service, "processRows", rows);
+
+        assertThat(result.processed()).isEqualTo(1);
+        assertThat(result.skippedFiles())
+                .extracting(MassImportService.SkippedFile::reason)
+                .containsExactly(MassImportService.SkipReason.INVALID_FILENAME_PATH_TRAVERSAL);
+    }
+
     // ─── importSingleDocument — non-blank optional fields ────────────────────
 
     @Test
@@ -651,7 +755,22 @@ class MassImportServiceTest {
         assertThat(spyService.getStatus().skipped()).isEqualTo(1);
         assertThat(spyService.getStatus().skippedFiles())
                 .extracting(MassImportService.SkippedFile::reason)
-                .containsExactly("FILE_READ_ERROR");
+                .containsExactly(MassImportService.SkipReason.FILE_READ_ERROR);
+    }
+
+    // ─── findFileRecursive — symlink escape security regression — do not remove ─
+
+    @Test
+    void findFileRecursive_throwsDomainException_whenSymlinkEscapesImportDir(
+            @TempDir Path importDirPath, @TempDir Path outsideDir) throws Exception {
+        Path outsideFile = outsideDir.resolve("secret.pdf");
+        Files.writeString(outsideFile, "sensitive content");
+        Files.createSymbolicLink(importDirPath.resolve("secret.pdf"), outsideFile);
+
+        ReflectionTestUtils.setField(service, "importDir", importDirPath.toString());
+
+        assertThatThrownBy(() -> ReflectionTestUtils.invokeMethod(service, "findFileRecursive", "secret.pdf"))
+                .isInstanceOf(DomainException.class);
     }
 
     // ─── readOds — XXE security regression ───────────────────────────────────

docker-compose.prod.yml

@@ -252,6 +252,8 @@ services:
       OTEL_METRICS_EXPORTER: none
       MANAGEMENT_METRICS_TAGS_APPLICATION: Familienarchiv
       MANAGEMENT_TRACING_SAMPLING_PROBABILITY: ${MANAGEMENT_TRACING_SAMPLING_PROBABILITY:-0.1}
+      SENTRY_DSN: ${SENTRY_DSN:-}
+      LOGGING_STRUCTURED_FORMAT_CONSOLE: ecs
     networks:
       - archiv-net
     healthcheck:
@@ -266,6 +268,10 @@ services:
     build:
       context: ./frontend
       target: production
+      args:
+        # Vite build-time variable — baked into the JS bundle at build time.
+        # Empty default so deploys succeed before the secret is configured.
+        VITE_SENTRY_DSN: ${VITE_SENTRY_DSN:-}
     restart: unless-stopped
     depends_on:
       backend:

docs/GLOSSARY.md

@@ -80,6 +80,14 @@ _See also [DocumentStatus lifecycle](#documentstatus-lifecycle)._
 
 **Sütterlin** — A specific standardized style of Kurrent taught in German schools from 1915 to 1941.
 
+**Illegible word** — a word whose recognition confidence falls below the configured threshold; replaced with the literal token `[unleserlich]` in the rendered block text and counted in the `ocr_illegible_words_total` Prometheus counter.
+
+**Models-ready gauge** — the `ocr_models_ready` Prometheus gauge, flipped from `0` to `1` once the FastAPI lifespan startup has finished loading the Kraken model and the spell-checker. Used both for the `/health` endpoint and as the supervised signal for the `ocr_models_ready < 1 for 2m` alert.
+
+**Recognition model accuracy** — the accuracy reported by `ketos train` for the recognition (text-line) model, exposed as `ocr_model_accuracy{kind="recognition"}`. Sourced from `_parse_best_checkpoint` on the highest-scoring checkpoint after training.
+
+**Segmentation model accuracy** — the accuracy reported by `ketos segtrain` for the baseline layout analysis (`blla`) model, exposed as `ocr_model_accuracy{kind="segmentation"}`. Distinct from recognition accuracy because the two models are trained and improved independently.
+
 ---
 
 ## Other Domain Terms

docs/OBSERVABILITY.md

@@ -118,11 +118,14 @@ To find a trace for a specific request in staging/production, either increase th
 
 ## Metrics (Prometheus → Grafana)
 
-Prometheus scrapes the backend management endpoint every 15 s:
+Prometheus scrapes two targets every 15 s:
 
 ```
 Target: backend:8081/actuator/prometheus
 Labels: job="spring-boot", application="Familienarchiv"
+
+Target: ocr:8000/metrics
+Labels: job="ocr-service"
 ```
 
 All Spring Boot metrics carry the `application="Familienarchiv"` tag, which is how the Grafana Spring Boot Observability dashboard (ID 17175) filters to this service.
@@ -146,6 +149,70 @@ jvm_memory_used_bytes{area="heap", application="Familienarchiv"}
 hikaricp_connections_active
 ```
 
+### OCR-service custom metrics
+
+Exposed at `ocr:8000/metrics` by `prometheus-fastapi-instrumentator`. The
+`http_*` metrics describe the FastAPI request layer; the `ocr_*` series are
+domain-specific. **Never label these with PII or document content** — labels
+have unbounded cardinality risk and are visible to anyone with Grafana access.
+
+| Metric | Type | Labels | Unit | What it tracks |
+|---|---|---|---|---|
+| `ocr_jobs_total` | Counter | `engine` (`surya`/`kraken`), `script_type` | jobs | OCR jobs that started after a successful PDF download |
+| `ocr_pages_total` | Counter | `engine` | pages | Successfully OCR'd pages in the streaming generator |
+| `ocr_skipped_pages_total` | Counter | — | pages | Pages skipped because the engine raised on them |
+| `ocr_words_total` | Counter | — | words | Recognized words summed across every block |
+| `ocr_illegible_words_total` | Counter | — | words | Words below the confidence threshold (rendered as `[unleserlich]`) |
+| `ocr_processing_seconds` | Histogram | `engine` | seconds | Per-page (stream) or per-document (`/ocr`) engine time, excluding preprocessing |
+| `ocr_training_runs_total` | Counter | `kind` (`recognition`/`segmentation`), `outcome` (`success`/`error`) | runs | Completed training runs |
+| `ocr_model_accuracy` | Gauge | `kind` | ratio (0–1) | Latest accuracy reported by a successful training run |
+| `ocr_models_ready` | Gauge | — | 0\|1 | 1 once the lifespan startup has finished loading models |
+
+Canonical example queries (the same ones referenced in issue #652):
+
+```promql
+# OCR throughput by engine
+sum by (engine) (rate(ocr_pages_total[5m]))
+
+# Share of words rendered as [unleserlich]
+sum(rate(ocr_illegible_words_total[5m]))
+  / sum(rate(ocr_words_total[5m]))
+
+# p95 page processing time per engine
+histogram_quantile(0.95, sum by (engine, le) (
+  rate(ocr_processing_seconds_bucket[5m])
+))
+
+# Training error rate
+sum(rate(ocr_training_runs_total{outcome="error"}[1h]))
+  / sum(rate(ocr_training_runs_total[1h]))
+
+# Latest recognition vs segmentation accuracy
+ocr_model_accuracy
+```
+
+### Internal-only endpoints
+
+`/metrics` is exposed by the OCR service over plain HTTP without
+authentication. The container is reachable only on the internal Docker
+network — Caddy never proxies to it directly. If the service is ever
+exposed (e.g. a `ports:` mapping is added), block the endpoint at the
+reverse proxy:
+
+```caddy
+ocr.example.com {
+    @internal_only path /metrics /health
+    respond @internal_only 404
+    reverse_proxy ocr:8000
+}
+```
+
+The `MetricsPathFilter` in `ocr-service/main.py` suppresses uvicorn's
+**stdout** access log lines for `/metrics` and `/health` so the container
+console stays focused on real OCR traffic. Promtail/Loki still receive
+access lines from any other source. Treat the filter as console
+noise-control, not an audit-suppression mechanism.
+
 ## Errors (GlitchTip)
 
 GlitchTip receives errors from both the backend (via Sentry Java SDK) and the frontend (via Sentry JavaScript SDK). It groups events by fingerprint, tracks first/last seen times, and links to the release that introduced the error.

docs/adr/023-prometheus-instrumentator-and-metrics-registry-injection.md

@@ -0,0 +1,94 @@
+# ADR-023: Prometheus Instrumentator and Metrics Registry Injection
+
+## Status
+
+Accepted
+
+## Context
+
+Until issue #652 the OCR service exposed no `/metrics` endpoint. The
+observability stack already scrapes the Spring Boot backend's actuator
+endpoint, but it had nothing to scrape on the Python side. Without HTTP-
+and domain-level metrics from `ocr-service` we cannot answer questions
+like "what is the share of words rendered as `[unleserlich]`" or
+"is the training error rate above its budget" from Grafana.
+
+Two implementation requirements influenced the design:
+
+1. **Counter / gauge isolation in tests.** `prometheus_client` collectors
+   are module-level singletons keyed by name on the global `REGISTRY`.
+   Re-importing or naively re-instantiating them raises a duplicated-
+   collector error and cross-test state leaks (a `.inc()` in test A is
+   still readable by test B). A test harness needs a way to swap the
+   active container for a fresh per-test instance.
+
+2. **Minimal blast radius on the request path.** We did not want to
+   hand-instrument every endpoint with FastAPI middleware. The
+   `prometheus-fastapi-instrumentator` library already provides
+   `http_requests_total`, `http_request_duration_seconds`, and the
+   `/metrics` exposition route, all idiomatic Prometheus names.
+
+## Decision
+
+- Add `prometheus-fastapi-instrumentator==7.0.0` and pin its transitive
+  dependency `prometheus-client==0.25.0` explicitly in
+  `ocr-service/requirements.txt`.
+- Mount the instrumentator once at module load:
+  `Instrumentator(excluded_handlers=["/health", "/metrics"]).instrument(app).expose(app)`.
+  This adds `/metrics` and an HTTP-level dashboard surface without
+  changing any endpoint code.
+- Define every domain metric (`ocr_jobs_total`, `ocr_pages_total`,
+  `ocr_processing_seconds`, …) inside a `build_metrics(registry)`
+  factory in `ocr-service/metrics.py` that returns a frozen `OcrMetrics`
+  dataclass. Production code binds the container to the default
+  `REGISTRY` once: `metrics: OcrMetrics = build_metrics(REGISTRY)`.
+- Tests use a `fresh_metrics` fixture that builds a new
+  `CollectorRegistry()` per test and monkeypatches `main.metrics` with
+  a container bound to it. The endpoint code keeps reading
+  `metrics.<name>` without knowing whether it is talking to the global
+  registry or a per-test one.
+
+## Consequences
+
+**Positive**
+
+- One reusable factory captures the metric definitions; future metrics
+  go in one place.
+- Tests run with full counter isolation. Cross-test state leakage is
+  impossible because each test sees its own dataclass instance.
+- The instrumentator gives us `http_*` metrics for free, including a
+  Grafana-ready histogram that pairs with the Spring Boot one.
+
+**Negative**
+
+- One extra level of indirection: any test that asserts on metric
+  values must remember to monkeypatch `main.metrics`, not the registry
+  directly. Rebinding through the registry is harmless but useless —
+  the dataclass holds references to the original collectors.
+- `prometheus-client` is now pinned. Upgrading it requires an explicit
+  bump and re-checking the instrumentator's compatibility range.
+- `/metrics` is exposed unauthenticated and relies on the Docker
+  internal network for confidentiality. See
+  [docs/OBSERVABILITY.md §Internal-only endpoints](../OBSERVABILITY.md)
+  for the Caddy snippet that must be added if the service ever gets a
+  host-side port mapping.
+
+## Alternatives considered
+
+- **Hand-roll the `/metrics` endpoint.** Rejected: would have meant
+  duplicating what `prometheus-fastapi-instrumentator` ships, plus
+  middleware for the HTTP histograms.
+- **Skip the factory; pass `registry` as a function argument
+  everywhere.** Rejected: clutters every endpoint signature and breaks
+  the symmetry with the Spring Boot side, which also relies on a
+  process-global Micrometer registry.
+- **Use a `pytest` autouse fixture that resets `REGISTRY` between
+  tests.** Rejected: `prometheus_client` does not expose a clean
+  "unregister all" hook, and we would be relying on private APIs.
+
+## References
+
+- Issue: [#652](https://git.raddatz.cloud/marcel/familienarchiv/issues/652)
+- Library: <https://github.com/trallnag/prometheus-fastapi-instrumentator>
+- Code: `ocr-service/metrics.py`, `ocr-service/main.py`,
+  `ocr-service/test_metrics.py`

docs/architecture/c4/l2-containers.puml

@@ -43,6 +43,8 @@ Rel(ocr, storage, "Fetches PDF via presigned URL", "HTTP / S3 presigned")
 Rel(mc, storage, "Bootstraps bucket + service account on startup", "MinIO Client CLI")
 Rel(promtail, loki, "Pushes log streams", "HTTP/Loki push API")
 Rel(backend, tempo, "Sends distributed traces via OTLP", "HTTP / OTLP / port 4318 (archiv-net)")
+Rel(prometheus, backend, "Scrapes JVM + HTTP metrics", "HTTP 8081 /actuator/prometheus")
+Rel(prometheus, ocr, "Scrapes OCR + http_* metrics", "HTTP 8000 /metrics")
 Rel(grafana, prometheus, "Queries metrics", "HTTP 9090")
 Rel(grafana, loki, "Queries logs", "HTTP 3100")
 Rel(grafana, tempo, "Queries traces", "HTTP 3200")

frontend/Dockerfile

@@ -16,6 +16,10 @@ CMD ["npm", "run", "dev"]
 # Compiles the SvelteKit Node-adapter output to /app/build.
 FROM node:20.19.0-alpine3.21 AS build
 WORKDIR /app
+# VITE_SENTRY_DSN is a build-time variable — Vite bakes it into the bundle.
+# Passed via docker-compose build.args; empty string disables the SDK.
+ARG VITE_SENTRY_DSN
+ENV VITE_SENTRY_DSN=$VITE_SENTRY_DSN
 COPY package.json package-lock.json ./
 RUN npm ci
 COPY . .

frontend/eslint.config.js

@@ -106,6 +106,31 @@ export default defineConfig(
 			]
 		}
 	},
+	{
+		// Forbid test fixtures (*.test-fixture.svelte) from being imported by
+		// production code. Tree-shaking keeps them out of the production bundle
+		// today (no route reaches them), but a lint rule makes the boundary
+		// explicit so an accidental autocomplete import in a route or component
+		// fails fast. Test files (*.spec.ts / *.test.ts) and the fixtures
+		// themselves are exempt — see the next block. Nora #2 on PR #629
+		// round 3.
+		files: ['**/*.svelte', '**/*.svelte.ts', '**/*.svelte.js', '**/*.ts'],
+		ignores: ['**/*.spec.ts', '**/*.test.ts', '**/*.test-fixture.svelte'],
+		rules: {
+			'no-restricted-imports': [
+				'error',
+				{
+					patterns: [
+						{
+							group: ['**/*.test-fixture.svelte'],
+							message:
+								'Test fixtures (*.test-fixture.svelte) are test-only — do not import from production code. Tracked by #637.'
+						}
+					]
+				}
+			]
+		}
+	},
 	{
 		plugins: { boundaries },
 		settings: {

frontend/messages/de.json

@@ -445,8 +445,12 @@
 	"person_mention_load_error": "Person konnte nicht geladen werden.",
 	"person_mention_loading": "Lade Person…",
 	"person_mention_popup_empty": "Keine Personen gefunden",
+	"person_mention_search_label": "Person suchen",
+	"person_mention_search_prompt": "Namen eingeben…",
 	"person_mention_btn_label": "Person verlinken",
 	"person_mention_create_new": "Neue Person anlegen",
+	"person_mention_results_count_singular": "1 Person gefunden",
+	"person_mention_results_count_plural": "{count} Personen gefunden",
 	"transcription_editor_aria_label": "Transkriptionstext",
 	"person_born_name_prefix": "geb.",
 	"page_title_home": "Archiv",
@@ -634,6 +638,9 @@
 	"transcription_block_review": "Als geprüft markieren",
 	"transcription_block_unreview": "Markierung aufheben",
 	"transcription_reviewed_count": "{reviewed} von {total} geprüft",
+	"transcription_mark_all_reviewed": "Alle als fertig markieren",
+	"transcription_mark_all_reviewed_disabled": "Alle Blöcke sind bereits als fertig markiert",
+	"transcription_mark_all_reviewed_error": "Markierung fehlgeschlagen. Bitte versuchen Sie es erneut.",
 	"training_ocr_heading": "Kurrent-Erkennung trainieren",
 	"training_ocr_description": "Starte ein neues Training mit den bisher geprüften OCR-Blöcken, um die Erkennungsgenauigkeit für Kurrentschrift zu verbessern.",
 	"training_ocr_blocks_ready": "{blocks} geprüfte Blöcke bereit / {docs} Dokumente",

frontend/messages/en.json

@@ -445,8 +445,12 @@
 	"person_mention_load_error": "Could not load person.",
 	"person_mention_loading": "Loading person…",
 	"person_mention_popup_empty": "No persons found",
+	"person_mention_search_label": "Search for a person",
+	"person_mention_search_prompt": "Enter a name…",
 	"person_mention_btn_label": "Link person",
 	"person_mention_create_new": "Create new person",
+	"person_mention_results_count_singular": "1 person found",
+	"person_mention_results_count_plural": "{count} persons found",
 	"transcription_editor_aria_label": "Transcription text",
 	"person_born_name_prefix": "née",
 	"page_title_home": "Archive",
@@ -634,6 +638,9 @@
 	"transcription_block_review": "Mark as reviewed",
 	"transcription_block_unreview": "Unmark as reviewed",
 	"transcription_reviewed_count": "{reviewed} of {total} reviewed",
+	"transcription_mark_all_reviewed": "Mark all as reviewed",
+	"transcription_mark_all_reviewed_disabled": "All blocks are already marked as reviewed",
+	"transcription_mark_all_reviewed_error": "Failed to mark all as reviewed. Please try again.",
 	"training_ocr_heading": "Train Kurrent recognition",
 	"training_ocr_description": "Start a new training run using the reviewed OCR blocks to improve recognition accuracy for Kurrent script.",
 	"training_ocr_blocks_ready": "{blocks} reviewed blocks ready / {docs} documents",

frontend/messages/es.json

@@ -445,8 +445,12 @@
 	"person_mention_load_error": "No se pudo cargar la persona.",
 	"person_mention_loading": "Cargando persona…",
 	"person_mention_popup_empty": "No se encontraron personas",
+	"person_mention_search_label": "Buscar persona",
+	"person_mention_search_prompt": "Escribe un nombre…",
 	"person_mention_btn_label": "Vincular persona",
 	"person_mention_create_new": "Crear nueva persona",
+	"person_mention_results_count_singular": "1 persona encontrada",
+	"person_mention_results_count_plural": "{count} personas encontradas",
 	"transcription_editor_aria_label": "Texto de transcripción",
 	"person_born_name_prefix": "n.",
 	"page_title_home": "Archivo",
@@ -634,6 +638,9 @@
 	"transcription_block_review": "Marcar como revisado",
 	"transcription_block_unreview": "Desmarcar como revisado",
 	"transcription_reviewed_count": "{reviewed} de {total} revisados",
+	"transcription_mark_all_reviewed": "Marcar todo como revisado",
+	"transcription_mark_all_reviewed_disabled": "Todos los bloques ya están marcados como revisados",
+	"transcription_mark_all_reviewed_error": "Error al marcar como revisado. Intente de nuevo.",
 	"training_ocr_heading": "Entrenar reconocimiento Kurrent",
 	"training_ocr_description": "Inicia un nuevo entrenamiento con los bloques OCR revisados para mejorar la precisión de reconocimiento del script Kurrent.",
 	"training_ocr_blocks_ready": "{blocks} bloques revisados listos / {docs} documentos",

frontend/src/lib/document/BulkDocumentEditLayout.svelte

@@ -17,6 +17,7 @@ import PdfViewer from '$lib/document/viewer/PdfViewer.svelte';
 import { bulkTitleFromFilename } from '$lib/document/filename';
 import type { Tag } from '$lib/tag/TagInput.svelte';
 import type { components } from '$lib/generated/api';
+import { withCsrf } from '$lib/shared/cookies';
 
 type Person = components['schemas']['Person'];
 
@@ -183,7 +184,10 @@ async function saveUpload() {
 		// FormData with per-chunk progress. Session cookie is sent automatically
 		// by the browser for same-origin requests.
 		try {
-			const res = await fetch('/api/documents/quick-upload', { method: 'POST', body: formData });
+			const res = await fetch(
+				'/api/documents/quick-upload',
+				withCsrf({ method: 'POST', body: formData })
+			);
 			const body = await res.json().catch(() => ({ errors: [] }));
 			const errorFilenames = new Set<string>(
 				(body.errors ?? []).map((err: { filename: string }) => err.filename)

frontend/src/lib/document/transcription/TranscriptionBlock.svelte.spec.ts

@@ -1,7 +1,7 @@
 import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
-import TranscriptionBlockHost from './TranscriptionBlock.test-host.svelte';
+import TranscriptionBlockHost from './TranscriptionBlock.test-fixture.svelte';
 import type { ConfirmService } from '$lib/shared/services/confirm.svelte.js';
 
 afterEach(cleanup);

frontend/src/lib/document/transcription/TranscriptionEditView.svelte

@@ -6,6 +6,7 @@ import TranscribeCoachEmptyState from '$lib/shared/help/TranscribeCoachEmptyStat
 import type { PersonMention, TranscriptionBlockData } from '$lib/shared/types';
 import { createBlockAutoSave } from '$lib/document/transcription/useBlockAutoSave.svelte';
 import { createBlockDragDrop } from '$lib/document/transcription/useBlockDragDrop.svelte';
+import { withCsrf } from '$lib/shared/cookies';
 
 type Props = {
 	documentId: string;
@@ -49,6 +50,7 @@ let activeBlockId: string | null = $state(null);
 let localLabels: string[] = $derived.by(() => [...trainingLabels]);
 let listEl: HTMLElement | null = $state(null);
 let markingAllReviewed = $state(false);
+let markAllError = $state<string | null>(null);
 
 const sortedBlocks = $derived([...blocks].sort((a, b) => a.sortOrder - b.sortOrder));
 const hasBlocks = $derived(blocks.length > 0);
@@ -67,8 +69,11 @@ $effect(() => {
 async function handleMarkAllReviewed() {
 	if (!onMarkAllReviewed) return;
 	markingAllReviewed = true;
+	markAllError = null;
 	try {
 		await onMarkAllReviewed();
+	} catch {
+		markAllError = m.transcription_mark_all_reviewed_error();
 	} finally {
 		markingAllReviewed = false;
 	}
@@ -109,11 +114,14 @@ function handleDelete(blockId: string) {
 
 async function reorder(newOrder: string[]) {
 	try {
-		const res = await fetch(`/api/documents/${documentId}/transcription-blocks/reorder`, {
+		const res = await fetch(
+			`/api/documents/${documentId}/transcription-blocks/reorder`,
+			withCsrf({
 				method: 'PUT',
 				headers: { 'Content-Type': 'application/json' },
 				body: JSON.stringify({ blockIds: newOrder })
-		});
+			})
+		);
 		if (!res.ok) return;
 		const updated = await res.json();
 		for (const b of updated) {
@@ -169,7 +177,7 @@ async function handleLabelToggle(label: string) {
 					<button
 						onclick={handleMarkAllReviewed}
 						disabled={allReviewed || markingAllReviewed}
-						title={allReviewed ? 'Alle Blöcke sind bereits als fertig markiert' : undefined}
+						title={allReviewed ? m.transcription_mark_all_reviewed_disabled() : undefined}
 						class="flex min-h-[44px] items-center gap-1.5 rounded-sm px-3 font-sans text-xs font-medium text-brand-navy/80 transition-colors hover:text-brand-navy focus-visible:ring-2 focus-visible:ring-brand-navy disabled:opacity-40"
 					>
 						{#if markingAllReviewed}
@@ -207,7 +215,7 @@ async function handleLabelToggle(label: string) {
 								<path stroke-linecap="round" stroke-linejoin="round" d="M5 13l4 4L19 7" />
 							</svg>
 						{/if}
-						Alle als fertig markieren
+						{m.transcription_mark_all_reviewed()}
 					</button>
 				{/if}
 			</div>
@@ -217,6 +225,31 @@ async function handleLabelToggle(label: string) {
 					style="width: {reviewProgress}%"
 				></div>
 			</div>
+			{#if markAllError}
+				<div
+					role="alert"
+					class="mt-1.5 flex items-center gap-2 rounded-sm border border-red-200 bg-red-50 px-3 py-2 font-sans text-sm text-red-700"
+				>
+					<span class="flex-1">{markAllError}</span>
+					<button
+						onclick={() => (markAllError = null)}
+						aria-label={m.comp_dismiss()}
+						class="flex min-h-[44px] min-w-[44px] items-center justify-center rounded text-red-600 hover:text-red-700 focus-visible:ring-2 focus-visible:ring-red-500"
+					>
+						<svg
+							class="h-4 w-4"
+							fill="none"
+							stroke="currentColor"
+							stroke-width="2"
+							viewBox="0 0 24 24"
+							xmlns="http://www.w3.org/2000/svg"
+							aria-hidden="true"
+						>
+							<path stroke-linecap="round" stroke-linejoin="round" d="M6 18L18 6M6 6l12 12" />
+						</svg>
+					</button>
+				</div>
+			{/if}
 		</div>
 		<div class="p-4">
 			<!-- svelte-ignore a11y_no_static_element_interactions -->

frontend/src/lib/document/transcription/TranscriptionEditView.svelte.spec.ts

@@ -3,6 +3,7 @@ import { cleanup, render } from 'vitest-browser-svelte';
 import { page, userEvent } from 'vitest/browser';
 import TranscriptionEditView from './TranscriptionEditView.svelte';
 import { createConfirmService, CONFIRM_KEY } from '$lib/shared/services/confirm.svelte.js';
+import { m } from '$lib/paraglide/messages.js';
 
 afterEach(cleanup);
 
@@ -312,14 +313,14 @@ describe('TranscriptionEditView — mark all reviewed', () => {
 			onMarkAllReviewed: vi.fn().mockResolvedValue(undefined)
 		});
 		await expect
-			.element(page.getByRole('button', { name: /Alle als fertig markieren/ }))
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
 			.toBeInTheDocument();
 	});
 
 	it('does not show "Alle als fertig markieren" button when onMarkAllReviewed is not provided', async () => {
 		renderView({ blocks: [unreviewedBlock1, unreviewedBlock2] });
 		await expect
-			.element(page.getByRole('button', { name: /Alle als fertig markieren/ }))
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
 			.not.toBeInTheDocument();
 	});
 
@@ -329,7 +330,7 @@ describe('TranscriptionEditView — mark all reviewed', () => {
 			onMarkAllReviewed: vi.fn().mockResolvedValue(undefined)
 		});
 		await expect
-			.element(page.getByRole('button', { name: /Alle als fertig markieren/ }))
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
 			.toBeDisabled();
 	});
 
@@ -343,7 +344,7 @@ describe('TranscriptionEditView — mark all reviewed', () => {
 		// userEvent.click() via Playwright CDP doesn't reliably trigger Svelte 5 onclick
 		// handlers when a TipTap editor is mounted in the same component tree.
 		const btn = (await page
-			.getByRole('button', { name: /Alle als fertig markieren/ })
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
 			.element()) as HTMLButtonElement;
 		btn.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
 		await vi.waitFor(() => expect(onMarkAllReviewed).toHaveBeenCalledTimes(1));
@@ -361,12 +362,83 @@ describe('TranscriptionEditView — mark all reviewed', () => {
 
 		// Same CDP click workaround: dispatch from browser JS to reliably fire Svelte 5 onclick
 		const btnEl = (await page
-			.getByRole('button', { name: /Alle als fertig markieren/ })
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
 			.element()) as HTMLButtonElement;
 		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
 		await expect
-			.element(page.getByRole('button', { name: /Alle als fertig markieren/ }))
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
 			.toBeDisabled();
 		resolveMarkAll();
 	});
+
+	it('shows error message when onMarkAllReviewed callback rejects', async () => {
+		const onMarkAllReviewed = vi.fn().mockRejectedValue(new Error('INTERNAL_ERROR'));
+		renderView({ blocks: [unreviewedBlock1, unreviewedBlock2], onMarkAllReviewed });
+
+		const btnEl = (await page
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
+			.element()) as HTMLButtonElement;
+		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+
+		await expect.element(page.getByRole('alert')).toBeInTheDocument();
+		await expect
+			.element(page.getByRole('alert'))
+			.toHaveTextContent(m.transcription_mark_all_reviewed_error());
+	});
+
+	it('clears error when dismiss button is clicked', async () => {
+		const onMarkAllReviewed = vi.fn().mockRejectedValue(new Error('INTERNAL_ERROR'));
+		renderView({ blocks: [unreviewedBlock1, unreviewedBlock2], onMarkAllReviewed });
+
+		const btnEl = (await page
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
+			.element()) as HTMLButtonElement;
+		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+		await expect.element(page.getByRole('alert')).toBeInTheDocument();
+
+		const dismissEl = (await page
+			.getByRole('button', { name: m.comp_dismiss() })
+			.element()) as HTMLButtonElement;
+		dismissEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+
+		await expect.element(page.getByRole('alert')).not.toBeInTheDocument();
+	});
+
+	it('clears error on next successful markAllReviewed call', async () => {
+		const onMarkAllReviewed = vi
+			.fn()
+			.mockRejectedValueOnce(new Error('INTERNAL_ERROR'))
+			.mockResolvedValue(undefined);
+		renderView({ blocks: [unreviewedBlock1, unreviewedBlock2], onMarkAllReviewed });
+
+		const btnEl = (await page
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
+			.element()) as HTMLButtonElement;
+		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+		await expect.element(page.getByRole('alert')).toBeInTheDocument();
+		// Wait for the button to be re-enabled before the second click — ensures the first
+		// async rejection has fully settled and Svelte has flushed state changes
+		await expect
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
+			.not.toBeDisabled();
+
+		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+
+		await expect.element(page.getByRole('alert')).not.toBeInTheDocument();
+	});
+
+	it('re-enables button after markAllReviewed failure', async () => {
+		const onMarkAllReviewed = vi.fn().mockRejectedValue(new Error('INTERNAL_ERROR'));
+		renderView({ blocks: [unreviewedBlock1, unreviewedBlock2], onMarkAllReviewed });
+
+		const btnEl = (await page
+			.getByRole('button', { name: m.transcription_mark_all_reviewed() })
+			.element()) as HTMLButtonElement;
+		btnEl.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true }));
+		await expect.element(page.getByRole('alert')).toBeInTheDocument();
+
+		await expect
+			.element(page.getByRole('button', { name: m.transcription_mark_all_reviewed() }))
+			.not.toBeDisabled();
+	});
 });

frontend/src/lib/document/transcription/useBlockAutoSave.svelte.ts

@@ -1,5 +1,6 @@
 import { SvelteMap } from 'svelte/reactivity';
 import type { PersonMention } from '$lib/shared/types';
+import { withCsrf } from '$lib/shared/cookies';
 
 export type SaveState = 'idle' | 'saving' | 'saved' | 'fading' | 'error';
 
@@ -116,12 +117,15 @@ export function createBlockAutoSave({ saveFn, documentId }: Options) {
 		for (const [blockId, text] of pendingTexts) {
 			const mentions = pendingMentions.get(blockId) ?? [];
 			clearDebounce(blockId);
-			void fetch(`/api/documents/${documentId}/transcription-blocks/${blockId}`, {
+			void fetch(
+				`/api/documents/${documentId}/transcription-blocks/${blockId}`,
+				withCsrf({
 					method: 'PUT',
 					headers: { 'Content-Type': 'application/json' },
 					body: JSON.stringify({ text, mentionedPersons: mentions }),
 					keepalive: true
-			});
+				})
+			);
 			pendingTexts.delete(blockId);
 			pendingMentions.delete(blockId);
 		}

frontend/src/lib/document/transcription/useTranscriptionBlocks.svelte.test.ts

@@ -259,12 +259,15 @@ describe('createTranscriptionBlocks.markAllReviewed', () => {
 		expect(ctrl.blocks.every((b) => b.reviewed)).toBe(true);
 	});
 
-	it('is a no-op when PUT returns non-OK', async () => {
+	it('throws and leaves blocks unchanged when PUT returns non-OK', async () => {
 		const fetchImpl = vi.fn(async (url: RequestInfo | URL, init?: RequestInit) => {
 			const u = url.toString();
 			const method = init?.method ?? 'GET';
 			if (u.includes('/review-all') && method === 'PUT') {
-				return new Response('', { status: 500 });
+				return new Response(JSON.stringify({ code: 'INTERNAL_ERROR' }), {
+					status: 500,
+					headers: { 'Content-Type': 'application/json' }
+				});
 			}
 			return new Response(JSON.stringify([baseBlock({ id: 'b-1', reviewed: false })]), {
 				status: 200,
@@ -274,7 +277,26 @@ describe('createTranscriptionBlocks.markAllReviewed', () => {
 
 		const ctrl = createTranscriptionBlocks({ documentId: () => 'doc-1', fetchImpl });
 		await ctrl.load();
-		await ctrl.markAllReviewed();
+		await expect(ctrl.markAllReviewed()).rejects.toThrow('INTERNAL_ERROR');
+		expect(ctrl.blocks[0].reviewed).toBe(false);
+	});
+
+	it('throws INTERNAL_ERROR when PUT returns non-JSON body (e.g. nginx 502)', async () => {
+		const fetchImpl = vi.fn(async (url: RequestInfo | URL, init?: RequestInit) => {
+			const u = url.toString();
+			const method = init?.method ?? 'GET';
+			if (u.includes('/review-all') && method === 'PUT') {
+				return new Response('Bad Gateway', { status: 502 });
+			}
+			return new Response(JSON.stringify([baseBlock({ id: 'b-1', reviewed: false })]), {
+				status: 200,
+				headers: { 'Content-Type': 'application/json' }
+			});
+		});
+
+		const ctrl = createTranscriptionBlocks({ documentId: () => 'doc-1', fetchImpl });
+		await ctrl.load();
+		await expect(ctrl.markAllReviewed()).rejects.toThrow('INTERNAL_ERROR');
 		expect(ctrl.blocks[0].reviewed).toBe(false);
 	});
 });

frontend/src/lib/document/transcription/useTranscriptionBlocks.svelte.ts

@@ -2,6 +2,7 @@
    lastEditedAt's $derived are scope-local to one computation; they're never
    stored on $state. */
 import type { TranscriptionBlockData, PersonMention } from '$lib/shared/types';
+import { makeCsrfFetch } from '$lib/shared/cookies';
 import { saveBlockWithConflictRetry } from './saveBlockWithConflictRetry';
 import { BlockConflictResolvedError } from './blockConflictMerge';
 
@@ -41,7 +42,7 @@ export function createTranscriptionBlocks(
 	options: TranscriptionBlocksOptions
 ): TranscriptionBlocksController {
 	const { documentId } = options;
-	const fetchImpl = options.fetchImpl ?? fetch;
+	const fetchImpl = makeCsrfFetch(options.fetchImpl ?? fetch);
 
 	let blocks = $state<TranscriptionBlockData[]>([]);
 	let annotationReloadKey = $state(0);
@@ -119,7 +120,11 @@ export function createTranscriptionBlocks(
 		const res = await fetchImpl(`/api/documents/${documentId()}/transcription-blocks/review-all`, {
 			method: 'PUT'
 		});
-		if (!res.ok) return;
+		if (!res.ok) {
+			const body = await res.json().catch(() => ({}));
+			// Never render body.message — route through getErrorMessage() to prevent leaking backend internals
+			throw new Error((body as { code?: string })?.code ?? 'INTERNAL_ERROR');
+		}
 		const updated = (await res.json()) as { id: string; reviewed: boolean }[];
 		for (const b of updated) {
 			const existing = blocks.find((x) => x.id === b.id);

frontend/src/lib/ocr/OcrTrainingCard.svelte

@@ -2,6 +2,7 @@
 import TrainingHistory from './TrainingHistory.svelte';
 import { m } from '$lib/paraglide/messages.js';
 import type { TrainingRun } from '$lib/ocr/training.js';
+import { withCsrf } from '$lib/shared/cookies';
 
 interface TrainingInfo {
 	availableBlocks?: number;
@@ -33,7 +34,7 @@ async function startTraining() {
 	successMessage = null;
 	errorMessage = null;
 	try {
-		const res = await fetch('/api/ocr/train', { method: 'POST' });
+		const res = await fetch('/api/ocr/train', withCsrf({ method: 'POST' }));
 		if (res.ok) {
 			successMessage = m.training_success();
 			setTimeout(() => {

frontend/src/lib/ocr/SegmentationTrainingCard.svelte

@@ -2,6 +2,7 @@
 import TrainingHistory from './TrainingHistory.svelte';
 import { m } from '$lib/paraglide/messages.js';
 import type { TrainingRun } from '$lib/ocr/training.js';
+import { withCsrf } from '$lib/shared/cookies';
 
 interface TrainingInfo {
 	availableSegBlocks?: number;
@@ -27,7 +28,7 @@ async function startTraining() {
 	training = true;
 	successMessage = null;
 	try {
-		const res = await fetch('/api/ocr/segtrain', { method: 'POST' });
+		const res = await fetch('/api/ocr/segtrain', withCsrf({ method: 'POST' }));
 		if (res.ok) {
 			successMessage = m.training_success();
 			setTimeout(() => {

frontend/src/lib/shared/api.server.spec.ts

@@ -0,0 +1,20 @@
+import { describe, it, expect } from 'vitest';
+import { extractErrorCode } from './api.server';
+
+describe('extractErrorCode', () => {
+	it('returns the code string when error has a code property', () => {
+		expect(extractErrorCode({ code: 'DOCUMENT_NOT_FOUND' })).toBe('DOCUMENT_NOT_FOUND');
+	});
+	it('returns undefined when error is undefined', () => {
+		expect(extractErrorCode(undefined)).toBeUndefined();
+	});
+	it('returns undefined when error is null', () => {
+		expect(extractErrorCode(null)).toBeUndefined();
+	});
+	it('returns undefined when error is a plain string', () => {
+		expect(extractErrorCode('oops')).toBeUndefined();
+	});
+	it('returns undefined when error object has no code property', () => {
+		expect(extractErrorCode({ message: 'fail' })).toBeUndefined();
+	});
+});

frontend/src/lib/shared/api.server.ts

@@ -23,3 +23,11 @@ export function createApiClient(fetch: typeof globalThis.fetch) {
 		fetch
 	});
 }
+
+export interface ApiError {
+	code?: string;
+}
+
+export function extractErrorCode(error: unknown): string | undefined {
+	return (error as ApiError | undefined)?.code;
+}

frontend/src/lib/shared/cookies.ts

@@ -1,3 +1,46 @@
+/**
+ * Reads the XSRF-TOKEN cookie set by Spring Security's CookieCsrfTokenRepository.
+ * Returns null outside the browser or when the cookie is absent.
+ */
+export function getCsrfToken(): string | null {
+	if (typeof document === 'undefined') return null;
+	const match = document.cookie.match(/(?:^|;\s*)XSRF-TOKEN=([^;]+)/);
+	return match ? decodeURIComponent(match[1]) : null;
+}
+
+/**
+ * Merges the X-XSRF-TOKEN header into a RequestInit so Spring Security's
+ * CSRF filter accepts the request. Safe to call server-side (no-op when the
+ * cookie is absent).
+ */
+export function withCsrf(init?: RequestInit): RequestInit {
+	const token = getCsrfToken();
+	if (!token) return init ?? {};
+	const headers = new Headers(init?.headers);
+	headers.set('X-XSRF-TOKEN', token);
+	return { ...init, headers };
+}
+
+/**
+ * Wraps a fetch implementation so that every state-mutating call (POST, PUT,
+ * PATCH, DELETE) automatically includes the X-XSRF-TOKEN header. GET/HEAD
+ * requests pass through unchanged.
+ *
+ * Used to CSRF-protect client-side hooks that accept an injectable fetchImpl.
+ * In unit tests the injected mock is wrapped but getCsrfToken() returns null
+ * (no browser cookie), so no header is added and existing test expectations
+ * are unaffected.
+ */
+export function makeCsrfFetch(inner: typeof fetch): typeof fetch {
+	return (input: RequestInfo | URL, init?: RequestInit): Promise<Response> => {
+		const method = (init?.method ?? 'GET').toUpperCase();
+		if (['POST', 'PUT', 'PATCH', 'DELETE'].includes(method)) {
+			return inner(input, withCsrf(init));
+		}
+		return inner(input, init);
+	};
+}
+
 /**
  * Extracts the fa_session cookie value from a list of Set-Cookie response headers.
  *

frontend/src/lib/shared/discussion/MentionDropdown.svelte

@@ -2,7 +2,18 @@
 import type { components } from '$lib/generated/api';
 // eslint-disable-next-line boundaries/dependencies -- mention dropdown needs person date formatting; extract to shared if it becomes reusable
 import { formatLifeDateRange } from '$lib/person/personLifeDates';
+import { untrack } from 'svelte';
 import { m } from '$lib/paraglide/messages.js';
+// Layered defence cap on the @mention search query length (CWE-400
+// amplification). The <input maxlength> attribute below caps direct
+// user edits, but the editor-mirror path (Tiptap contenteditable -> mirror
+// $effect -> searchQuery) is not covered by `maxlength` since the
+// contenteditable has no such enforcement. Clipping at the mirror keeps
+// the cap honest from both paths. Tracked server-side separately.
+// Nora #1 on PR #629. Hoisted to mentionConstants.ts so the host editor
+// (PersonMentionEditor) can clip the inserted displayName to the same cap
+// — see Felix #3 on PR #629.
+import { MAX_QUERY_LENGTH } from './mentionConstants';
 
 type Person = components['schemas']['Person'];
 
@@ -17,7 +28,46 @@ type DropdownState = {
 	clientRect: (() => DOMRect | null) | null;
 };
 
-let { model }: { model: DropdownState } = $props();
+let {
+	model,
+	editorQuery = '',
+	onSearch = () => {}
+}: {
+	model: DropdownState;
+	/** Text typed after `@` in the host editor. Mirrors into the search input
+	 *  until the user takes manual ownership by typing into the input itself. */
+	editorQuery?: string;
+	onSearch?: (query: string) => void;
+} = $props();
+
+let searchQuery = $state(untrack(() => editorQuery.slice(0, MAX_QUERY_LENGTH)));
+let userHasEdited = $state(false);
+
+// Intent-revealing alias used by both the persistent aria-live announcer and
+// the visible empty-state copy. Folding the duplicated rule into one $derived
+// keeps the two branches in lockstep. Felix #3 on PR #629 round 4.
+const isQueryEmpty = $derived(searchQuery.trim() === '');
+
+// Mirror the editor's typed text until the user takes ownership.
+//
+// Why `$state + $effect` (not `$derived`): `searchQuery` is also written by
+// `bind:value` on the <input> below, so it needs to be a mutable `$state`.
+// A `$derived` would be read-only and would clobber direct user edits on
+// every editor keystroke. The `userHasEdited` latch pins ownership once the
+// user types into the input. Felix #1 on PR #629.
+$effect(() => {
+	if (!userHasEdited) {
+		searchQuery = editorQuery.slice(0, MAX_QUERY_LENGTH);
+	}
+});
+
+// Fire onSearch whenever the effective query changes — covers both the
+// editor mirror and direct input edits. This is the only place onSearch
+// fires; when the dropdown is unmounted, the effect is disposed and no
+// further fetches occur.
+$effect(() => {
+	onSearch(searchQuery);
+});
 
 // highlightedIndex must be both writable (keyboard handler mutates it) and
 // reset when `items` changes (so it never points past the end of a new list).
@@ -112,16 +162,70 @@ function selectItem(item: Person) {
 	unauthenticated users.
 -->
 <div
-	class="fixed z-50 w-72 overflow-hidden rounded-sm border border-line bg-surface shadow-lg"
+	class="fixed z-50 w-72 max-w-[calc(100vw-1rem)] overflow-hidden rounded-sm border border-line bg-surface shadow-lg"
 	role="listbox"
 	aria-label={m.person_mention_btn_label()}
 	style:top={position.top}
 	style:bottom={position.bottom}
 	style:left={position.left}
 >
+	<div class="border-b border-line px-3 py-2">
+		<label class="sr-only" for="mention-search">{m.person_mention_search_label()}</label>
+		<div class="flex items-center gap-2">
+			<svg
+				aria-hidden="true"
+				viewBox="0 0 24 24"
+				fill="none"
+				stroke="currentColor"
+				stroke-width="2"
+				class="h-5 w-5 shrink-0 text-ink-2"
+			>
+				<circle cx="11" cy="11" r="7" />
+				<path d="m20 20-3.5-3.5" stroke-linecap="round" />
+			</svg>
+			<input
+				id="mention-search"
+				type="search"
+				data-test-search-input
+				maxlength={MAX_QUERY_LENGTH}
+				class="min-h-[44px] w-full bg-transparent font-sans text-base text-ink placeholder:text-ink-3 focus:outline-none focus-visible:ring-2 focus-visible:ring-brand-navy focus-visible:ring-inset"
+				placeholder={m.person_mention_search_prompt()}
+				bind:value={searchQuery}
+				oninput={() => {
+					userHasEdited = true;
+				}}
+				onmousedown={(e) => e.stopPropagation()}
+			/>
+		</div>
+	</div>
+	<!--
+		Persistent aria-live region — lives ABOVE the conditional branches so the
+		element never unmounts when items transition between empty and populated.
+		VoiceOver in particular swallows announcements from freshly-mounted live
+		regions, and the previous (conditional-inside) markup silently dropped
+		the "N persons found" announcement when results populated. Leonie #3 on
+		PR #629 round 3.
+	-->
+	<p class="sr-only" aria-live="polite">
 		{#if model.items.length === 0}
-		<p class="px-3 py-2.5 font-sans text-sm text-ink-3">
+			{isQueryEmpty ? m.person_mention_search_prompt() : m.person_mention_popup_empty()}
-			{m.person_mention_popup_empty()}
+		{:else if model.items.length === 1}
+			{m.person_mention_results_count_singular()}
+		{:else}
+			{m.person_mention_results_count_plural({ count: model.items.length })}
+		{/if}
+	</p>
+	{#if model.items.length === 0}
+		<!--
+			Visible empty-state copy — visual-only. The persistent sr-only <p>
+			above is the sole AT announcer; this one is hidden from screen readers
+			via aria-hidden="true" so VoiceOver does not double-announce
+			(NVDA de-dups, VoiceOver does not). Leonie S-2 on PR #629 round 4.
+			Do NOT add an aria-live attribute here — that would re-introduce
+			the duplicate announcement.
+		-->
+		<p aria-hidden="true" class="px-3 py-2.5 font-sans text-sm text-ink-3">
+			{isQueryEmpty ? m.person_mention_search_prompt() : m.person_mention_popup_empty()}
 		</p>
 		<!--
 			Empty-state escape hatch — without it the transcriber has to close
@@ -132,7 +236,7 @@ function selectItem(item: Person) {
 		<a
 			href="/persons/new"
 			target="_blank"
-			rel="noopener"
+			rel="noopener noreferrer"
 			class="flex min-h-[44px] items-center gap-2 border-t border-line px-3 py-2.5 font-sans text-sm font-medium text-brand-navy hover:bg-canvas focus:bg-canvas focus:outline-none"
 			onmousedown={(e) => e.preventDefault()}
 		>

frontend/src/lib/shared/discussion/MentionDropdown.svelte.test.ts

@@ -1,22 +1,37 @@
 import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
-import { page } from 'vitest/browser';
+import { page, userEvent } from 'vitest/browser';
+import { flushSync, mount, tick, unmount } from 'svelte';
 import MentionDropdown from './MentionDropdown.svelte';
+import MentionDropdownFixture from './MentionDropdown.test-fixture.svelte';
+import { m } from '$lib/paraglide/messages.js';
+import type { components } from '$lib/generated/api';
+
+type Person = components['schemas']['Person'];
 
 afterEach(cleanup);
 
-const makePerson = (id: string, name: string, overrides: Record<string, unknown> = {}) => ({
+const makePerson = (id: string, name: string, overrides: Partial<Person> = {}): Person => {
+	const parts = name.split(' ');
+	return {
 		id,
-	firstName: name.split(' ')[0] ?? null,
+		firstName: parts[0],
-	lastName: name.split(' ').slice(1).join(' ') || name,
+		lastName: parts.slice(1).join(' ') || name,
 		displayName: name,
-	birthYear: null as number | null,
+		personType: 'PERSON',
-	deathYear: null as number | null,
+		familyMember: false,
 		...overrides
-});
+	};
+};
 
-const baseModel = (overrides: Record<string, unknown> = {}) => ({
+type DropdownState = {
-	items: [] as ReturnType<typeof makePerson>[],
+	items: Person[];
+	command: (item: Person) => void;
+	clientRect: (() => DOMRect | null) | null;
+};
+
+const baseModel = (overrides: Partial<DropdownState> = {}): DropdownState => ({
+	items: [],
 	command: vi.fn(),
 	clientRect: () => new DOMRect(100, 100, 0, 24),
 	...overrides
@@ -29,14 +44,32 @@ describe('MentionDropdown', () => {
 		await expect.element(page.getByRole('listbox', { name: /person verlinken/i })).toBeVisible();
 	});
 
-	it('renders the empty placeholder when items is empty', async () => {
+	it('shows the "enter a name" prompt when the search field is empty', async () => {
 		render(MentionDropdown, { props: { model: baseModel() } });
 
-		await expect.element(page.getByText('Keine Personen gefunden')).toBeVisible();
+		// Scope to the visible empty-state <p> (text-ink-3) — the persistent
+		// sr-only aria-live region above also contains the same prompt copy.
+		const visibleEmptyP = document.querySelector(
+			'[role="listbox"] p.text-ink-3'
+		) as HTMLElement | null;
+		expect(visibleEmptyP).not.toBeNull();
+		expect(visibleEmptyP!.textContent ?? '').toContain(m.person_mention_search_prompt());
+		expect(visibleEmptyP!.textContent ?? '').not.toContain(m.person_mention_popup_empty());
+	});
+
+	it('shows "no persons found" when the search has a query but the list is empty', async () => {
+		render(MentionDropdown, { props: { model: baseModel(), editorQuery: 'WdG' } });
+
+		const visibleEmptyP = document.querySelector(
+			'[role="listbox"] p.text-ink-3'
+		) as HTMLElement | null;
+		expect(visibleEmptyP).not.toBeNull();
+		expect(visibleEmptyP!.textContent ?? '').toContain(m.person_mention_popup_empty());
+		expect(visibleEmptyP!.textContent ?? '').not.toContain(m.person_mention_search_prompt());
 	});
 
 	it('shows the create-new escape hatch link in the empty state', async () => {
-		render(MentionDropdown, { props: { model: baseModel() } });
+		render(MentionDropdown, { props: { model: baseModel(), editorQuery: 'unknown' } });
 
 		const link = (await page
 			.getByRole('link', { name: /neue person anlegen/i })
@@ -44,6 +77,7 @@ describe('MentionDropdown', () => {
 		expect(link.href).toContain('/persons/new');
 		expect(link.target).toBe('_blank');
 		expect(link.rel).toContain('noopener');
+		expect(link.rel).toContain('noreferrer');
 	});
 
 	it('renders one option per item when populated', async () => {
@@ -104,3 +138,315 @@ describe('MentionDropdown', () => {
 		expect(dropdown.style.left).toBe('123px');
 	});
 });
+
+// ─── Search input — Issue #380 ────────────────────────────────────────────────
+
+describe('MentionDropdown — search input', () => {
+	it('renders a search input pre-filled with the editorQuery prop', async () => {
+		render(MentionDropdown, {
+			props: { model: baseModel(), editorQuery: 'WdG' }
+		});
+
+		await expect.element(page.getByRole('searchbox')).toHaveValue('WdG');
+	});
+
+	it('exposes a data-test-search-input attribute for E2E selectors', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const input = document.querySelector('[data-test-search-input]');
+		expect(input).not.toBeNull();
+		expect((input as HTMLInputElement).type).toBe('search');
+	});
+
+	it('search input wrapper meets the 44px touch target (WCAG 2.2 AA)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const input = document.querySelector('[data-test-search-input]') as HTMLElement;
+		expect(input).not.toBeNull();
+		expect(input.className).toContain('min-h-[44px]');
+	});
+
+	it('renders a persistent aria-live="polite" region (does not remount on items transition; Leonie #3 on PR #629)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const listbox = document.querySelector('[role="listbox"]');
+		expect(listbox).not.toBeNull();
+		const live = listbox!.querySelector('p[aria-live="polite"]');
+		expect(live).not.toBeNull();
+		// Empty + empty-query → "Namen eingeben…" prompt
+		expect(live!.textContent ?? '').toContain(m.person_mention_search_prompt());
+	});
+
+	it('announces the result count in the persistent live region when items populate (Leonie #3 on PR #629)', async () => {
+		render(MentionDropdown, {
+			props: {
+				model: baseModel({
+					items: [
+						makePerson('p1', 'Anna Schmidt'),
+						makePerson('p2', 'Bert Meier'),
+						makePerson('p3', 'Carl Vogel')
+					]
+				})
+			}
+		});
+
+		const listbox = document.querySelector('[role="listbox"]');
+		expect(listbox).not.toBeNull();
+		const live = listbox!.querySelector('p[aria-live="polite"]');
+		expect(live).not.toBeNull();
+		// Populated → "3 Personen gefunden" (plural)
+		expect(live!.textContent ?? '').toContain('3');
+	});
+
+	it('announces the singular form when exactly one item is present (Sara #4 on PR #629)', async () => {
+		render(MentionDropdown, {
+			props: {
+				model: baseModel({
+					items: [makePerson('p1', 'Anna Schmidt')]
+				})
+			}
+		});
+
+		const listbox = document.querySelector('[role="listbox"]');
+		expect(listbox).not.toBeNull();
+		const live = listbox!.querySelector('p[aria-live="polite"]');
+		expect(live).not.toBeNull();
+		// Singular branch — "1 Person gefunden" / "1 person found" / "1 persona encontrada"
+		// (locale-dependent; resolved via the Paraglide message helper).
+		expect(live!.textContent ?? '').toContain(m.person_mention_results_count_singular());
+	});
+
+	it('keeps the visible empty-state copy without its own aria-live and hides it from AT (Leonie #3 on PR #629 round 3; Leonie S-2 round 4)', async () => {
+		render(MentionDropdown, { props: { model: baseModel(), editorQuery: 'WdG' } });
+
+		// Visible empty-state <p> exists with the empty-result copy ...
+		const empty = document.querySelector('p.text-ink-3') as HTMLElement | null;
+		expect(empty).not.toBeNull();
+		expect(empty!.textContent ?? '').toContain(m.person_mention_popup_empty());
+		// ... but it must NOT carry its own aria-live (the persistent sr-only
+		// region above the conditional is the announcer now).
+		expect(empty!.hasAttribute('aria-live')).toBe(false);
+		// ... and it MUST be hidden from screen readers via aria-hidden="true"
+		// so VoiceOver does not double-announce (the persistent sr-only region
+		// is the sole AT source of truth). Leonie S-2 on PR #629 round 4.
+		expect(empty!.getAttribute('aria-hidden')).toBe('true');
+	});
+
+	it('renders the magnifier icon at h-5 w-5 with text-ink-2 (Leonie BLOCKER on PR #629)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const icon = document.querySelector('[data-test-search-input]')
+			?.previousElementSibling as SVGElement | null;
+		expect(icon).not.toBeNull();
+		expect(icon!.tagName.toLowerCase()).toBe('svg');
+		expect(icon!.getAttribute('class') ?? '').toContain('h-5');
+		expect(icon!.getAttribute('class') ?? '').toContain('w-5');
+		expect(icon!.getAttribute('class') ?? '').toContain('text-ink-2');
+	});
+
+	it('caps the search input at maxlength=100 (CWE-400 amplification — Nora on PR #629)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const input = document.querySelector('[data-test-search-input]') as HTMLInputElement;
+		expect(input).not.toBeNull();
+		expect(input.maxLength).toBe(100);
+	});
+
+	it('clips a long editorQuery mirror to 100 chars (CWE-400 layered — Nora #1 on PR #629)', async () => {
+		const longQuery = 'A'.repeat(200);
+		render(MentionDropdown, { props: { model: baseModel(), editorQuery: longQuery } });
+
+		const input = document.querySelector('[data-test-search-input]') as HTMLInputElement;
+		expect(input).not.toBeNull();
+		expect(input.value.length).toBe(100);
+		expect(input.value).toBe('A'.repeat(100));
+	});
+
+	it('caps the listbox width to the viewport (320 px reflow guard — Leonie FINDING-MENTION-005)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const listbox = document.querySelector('[role="listbox"]') as HTMLElement;
+		expect(listbox).not.toBeNull();
+		expect(listbox.className).toContain('max-w-[calc(100vw-1rem)]');
+	});
+
+	it('renders the @mention search input at text-base (16 px senior-audience floor — Leonie FINDING-MENTION-006)', async () => {
+		render(MentionDropdown, { props: { model: baseModel() } });
+
+		const input = document.querySelector('[data-test-search-input]') as HTMLInputElement;
+		expect(input).not.toBeNull();
+		expect(input.className).toContain('text-base');
+		expect(input.className).not.toContain('text-sm');
+	});
+
+	it('invokes onSearch with the current value whenever the user types', async () => {
+		const onSearch = vi.fn();
+		render(MentionDropdown, { props: { model: baseModel(), onSearch } });
+
+		await userEvent.type(page.getByRole('searchbox'), 'Walter');
+
+		await vi.waitFor(() => {
+			expect(onSearch).toHaveBeenCalled();
+			expect(onSearch).toHaveBeenLastCalledWith('Walter');
+		});
+	});
+
+	it('keeps the user-edited search value when editorQuery changes after the takeover (Felix on PR #629)', async () => {
+		let setEditorQuery!: (q: string) => void;
+		render(MentionDropdownFixture, {
+			model: baseModel(),
+			initialEditorQuery: 'WdG',
+			onReady: (s: (q: string) => void) => {
+				setEditorQuery = s;
+			}
+		});
+
+		await expect.element(page.getByRole('searchbox')).toHaveValue('WdG');
+
+		await page.getByRole('searchbox').fill('Walter');
+		await expect.element(page.getByRole('searchbox')).toHaveValue('Walter');
+
+		setEditorQuery('WdGruyter');
+		// Flush pending Svelte reactivity so any (non-)update from the mirror
+		// $effect has landed before we assert. expect.element already polls, so
+		// no fixed-timeout fallback is needed. Sara on PR #629 round 3.
+		await tick();
+
+		await expect.element(page.getByRole('searchbox')).toHaveValue('Walter');
+	});
+});
+
+// ─── ArrowDown via exported onKeyDown (Sara #3 on PR #629) ──────────────────
+//
+// In production, Tiptap intercepts ArrowDown/ArrowUp/Enter at the editor level
+// and forwards them to the dropdown via its exported onKeyDown(event) function
+// — the dropdown itself has no DOM keydown listener. This test exercises the
+// same export so a regression in highlightedIndex/selection logic is caught
+// at the unit level. The full E2E focus-chain test is deferred to a separate
+// issue (Playwright).
+//
+// These unit tests directly invoke the exported `onKeyDown` to pin its
+// behaviour in isolation. They do NOT exercise the Tiptap forwarding
+// chain (PersonMentionEditor.suggestion.render() returning { onKeyDown })
+// — that integration is covered by the 'ArrowDown moves the highlight'
+// test in PersonMentionEditor.svelte.spec.ts. Sara on PR #629 round 3.
+
+describe('MentionDropdown — onKeyDown forwarding', () => {
+	// flushSync ensures Svelte reactivity propagation completes before
+	// asserting (uniform across all four key tests so the next reader
+	// doesn't have to figure out why some are wrapped and others aren't).
+	// Felix #1 suggestion on PR #629 round 3.
+
+	it('ArrowDown advances aria-selected to the next option in the listbox', async () => {
+		const container = document.createElement('div');
+		document.body.appendChild(container);
+		const instance = mount(MentionDropdown, {
+			target: container,
+			props: {
+				model: baseModel({
+					items: [makePerson('p1', 'Anna Schmidt'), makePerson('p2', 'Bert Meier')]
+				})
+			}
+		});
+		try {
+			const exports = instance as unknown as { onKeyDown: (e: KeyboardEvent) => boolean };
+
+			// First option starts highlighted.
+			const first = container.querySelector('[data-test-person-id="p1"]') as HTMLElement;
+			const second = container.querySelector('[data-test-person-id="p2"]') as HTMLElement;
+			expect(first.getAttribute('aria-selected')).toBe('true');
+			expect(second.getAttribute('aria-selected')).toBe('false');
+
+			let consumed = false;
+			flushSync(() => {
+				consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'ArrowDown' }));
+			});
+			expect(consumed).toBe(true);
+
+			expect(first.getAttribute('aria-selected')).toBe('false');
+			expect(second.getAttribute('aria-selected')).toBe('true');
+		} finally {
+			unmount(instance);
+			container.remove();
+		}
+	});
+
+	it('ArrowUp wraps from the first option to the last', async () => {
+		const container = document.createElement('div');
+		document.body.appendChild(container);
+		const instance = mount(MentionDropdown, {
+			target: container,
+			props: {
+				model: baseModel({
+					items: [makePerson('p1', 'Anna Schmidt'), makePerson('p2', 'Bert Meier')]
+				})
+			}
+		});
+		try {
+			const exports = instance as unknown as { onKeyDown: (e: KeyboardEvent) => boolean };
+
+			let consumed = false;
+			flushSync(() => {
+				consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'ArrowUp' }));
+			});
+			expect(consumed).toBe(true);
+
+			const second = container.querySelector('[data-test-person-id="p2"]') as HTMLElement;
+			expect(second.getAttribute('aria-selected')).toBe('true');
+		} finally {
+			unmount(instance);
+			container.remove();
+		}
+	});
+
+	it('Enter invokes model.command with the currently highlighted item', async () => {
+		const command = vi.fn();
+		const container = document.createElement('div');
+		document.body.appendChild(container);
+		const instance = mount(MentionDropdown, {
+			target: container,
+			props: {
+				model: baseModel({
+					items: [makePerson('p1', 'Anna Schmidt'), makePerson('p2', 'Bert Meier')],
+					command
+				})
+			}
+		});
+		try {
+			const exports = instance as unknown as { onKeyDown: (e: KeyboardEvent) => boolean };
+
+			let consumed = false;
+			flushSync(() => {
+				consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'Enter' }));
+			});
+			expect(consumed).toBe(true);
+			expect(command).toHaveBeenCalledTimes(1);
+			expect(command.mock.calls[0][0].id).toBe('p1');
+		} finally {
+			unmount(instance);
+			container.remove();
+		}
+	});
+
+	it('Escape returns false so the suggestion plugin can handle it', async () => {
+		const container = document.createElement('div');
+		document.body.appendChild(container);
+		const instance = mount(MentionDropdown, {
+			target: container,
+			props: {
+				model: baseModel({ items: [makePerson('p1', 'Anna Schmidt')] })
+			}
+		});
+		try {
+			const exports = instance as unknown as { onKeyDown: (e: KeyboardEvent) => boolean };
+			let consumed = true;
+			flushSync(() => {
+				consumed = exports.onKeyDown(new KeyboardEvent('keydown', { key: 'Escape' }));
+			});
+			expect(consumed).toBe(false);
+		} finally {
+			unmount(instance);
+			container.remove();
+		}
+	});
+});

frontend/src/lib/shared/discussion/MentionDropdown.test-fixture.svelte

@@ -0,0 +1,32 @@
+<script lang="ts">
+import { untrack } from 'svelte';
+import MentionDropdown from './MentionDropdown.svelte';
+import type { components } from '$lib/generated/api';
+
+type Person = components['schemas']['Person'];
+type DropdownState = {
+	items: Person[];
+	command: (item: Person) => void;
+	clientRect: (() => DOMRect | null) | null;
+};
+
+type Props = {
+	model: DropdownState;
+	initialEditorQuery: string;
+	/** Test hook: receives a setter for editorQuery so the test can mutate it. */
+	onReady?: (setEditorQuery: (q: string) => void) => void;
+	onSearch?: (q: string) => void;
+};
+
+let { model, initialEditorQuery, onReady, onSearch = () => {} }: Props = $props();
+
+let editorQuery = $state(untrack(() => initialEditorQuery));
+
+$effect(() => {
+	onReady?.((q) => {
+		editorQuery = q;
+	});
+});
+</script>
+
+<MentionDropdown model={model} editorQuery={editorQuery} onSearch={onSearch} />

frontend/src/lib/shared/discussion/PersonMentionEditor.svelte

@@ -7,7 +7,9 @@ import { m } from '$lib/paraglide/messages.js';
 import type { components } from '$lib/generated/api';
 import type { PersonMention } from '$lib/shared/types';
 import { deserialize, serialize } from '$lib/shared/discussion/mentionSerializer';
+import { debounce } from '$lib/shared/utils/debounce';
 import MentionDropdown from './MentionDropdown.svelte';
+import { MAX_QUERY_LENGTH, SEARCH_DEBOUNCE_MS, SEARCH_RESULT_LIMIT } from './mentionConstants';
 
 type Person = components['schemas']['Person'];
 
@@ -33,6 +35,13 @@ let {
 
 let editorEl: HTMLDivElement;
 let editor: Editor | null = null;
+// Hoisted so onDestroy can guarantee the imperatively-mounted dropdown is
+// torn down even if Tiptap's suggestion plugin onExit didn't fire (e.g. when
+// the host component is unmounted while the dropdown is still open).
+let mountedDropdown: object | null = null;
+// Hoisted so onDestroy can cancel any pending fetch — otherwise a trailing
+// debounced search can fire after the editor is gone and pollute later tests.
+let cancelPendingSearch: (() => void) | null = null;
 
 // Single reactive state object shared with MentionDropdown. Mutating these
 // fields propagates to the mounted dropdown via Svelte's $state proxy —
@@ -42,10 +51,12 @@ let dropdownState = $state<{
 	items: Person[];
 	command: (item: Person) => void;
 	clientRect: (() => DOMRect | null) | null;
+	editorQuery: string;
 }>({
 	items: [],
 	command: () => {},
-	clientRect: null
+	clientRect: null,
+	editorQuery: ''
 });
 
 type DropdownExports = {
@@ -138,16 +149,13 @@ onMount(() => {
 					// Nora #5618 #3 — separate issue tracks the GET /api/persons
 					// response-shape audit (PersonSummaryDTO leaks `notes`).
 					// ─────────────────────────────────────────────────────────────
-					items: async ({ query }: { query: string }) => {
+					// Tiptap's suggestion plugin requires an `items()` callback to keep
-						if (!query) return [];
+					// the dropdown alive, but the actual fetch is owned by `runSearch`
-						try {
+					// below — routed through the dropdown's search input via the
-							const res = await fetch(`/api/persons?q=${encodeURIComponent(query)}`);
+					// debounced `onSearch` channel. Returning `[]` here keeps Tiptap
-							if (!res.ok) return [];
+					// happy without firing a duplicate per-keystroke fetch.
-							return ((await res.json()) as Person[]).slice(0, 5);
+					// Markus #5616 / Felix / Nora / Sara on PR #629.
-						} catch {
+					items: async () => [],
-							return [];
-						}
-					},
 					// AC-1 fix: insert the typed query as displayName, not person.displayName.
 					command({ editor: ed, range, props }) {
 						const p = props as unknown as { personId: string; displayName: string };
@@ -165,7 +173,6 @@ onMount(() => {
 							.run();
 					},
 					render() {
-						let component: object | null = null;
 						let exports: DropdownExports | null = null;
 
 						// Tiptap's SuggestionProps types `command` against the default
@@ -178,25 +185,84 @@ onMount(() => {
 							clientRect?: (() => DOMRect | null) | null;
 						};
 
+						// Request-token guard: every onSearch invocation bumps `requestId`;
+						// runSearch captures the id active when its fetch starts and discards
+						// the response if a newer onSearch has fired since. Without this, a
+						// late response can repopulate the dropdown after the user cleared
+						// the search input. Sara on PR #629.
+						let requestId = 0;
+						const runSearch = async (query: string) => {
+							const id = requestId;
+							try {
+								// Defensive client-side cap — server-side enforcement is tracked
+								// separately. Markus on PR #629.
+								const res = await fetch(
+									`/api/persons?q=${encodeURIComponent(query)}&limit=${SEARCH_RESULT_LIMIT}`
+								);
+								if (id !== requestId) return;
+								if (!res.ok) {
+									dropdownState.items = [];
+									return;
+								}
+								const data = (await res.json()) as Person[];
+								if (id !== requestId) return;
+								dropdownState.items = data.slice(0, SEARCH_RESULT_LIMIT);
+							} catch {
+								if (id !== requestId) return;
+								dropdownState.items = [];
+							}
+						};
+						const debouncedSearch = debounce(runSearch, SEARCH_DEBOUNCE_MS);
+						cancelPendingSearch = () => debouncedSearch.cancel();
+						const onSearch = (query: string) => {
+							requestId++;
+							if (query.trim() === '') {
+								debouncedSearch.cancel();
+								dropdownState.items = [];
+								return;
+							}
+							debouncedSearch(query);
+						};
+
 						const updateState = (renderProps: LooseRenderProps) => {
-							dropdownState.items = renderProps.items as Person[];
+							// Clip once here so both the inserted displayName and the
+							// dropdown's editor-mirror see the same value. The dropdown
+							// already clips the mirror (Nora #1 CWE-400), but without
+							// clipping at the command boundary an unclipped query would
+							// still flow through as the inserted displayName — visible
+							// UI divergence between "what I searched" and "what was
+							// inserted". Felix #3 on PR #629.
+							const clippedQuery = renderProps.query.slice(0, MAX_QUERY_LENGTH);
 							// AC-1: pass typed query as displayName, not person.displayName
 							dropdownState.command = (item: Person) =>
 								renderProps.command({
 									personId: item.id,
-									displayName: renderProps.query
+									displayName: clippedQuery
 								});
 							dropdownState.clientRect = renderProps.clientRect ?? null;
+							dropdownState.editorQuery = clippedQuery;
 						};
 
 						return {
 							onStart(renderProps) {
-								updateState(renderProps as unknown as LooseRenderProps);
+								const loose = renderProps as unknown as LooseRenderProps;
+								updateState(loose);
+								// MentionDropdown reads `editorQuery` off the shared state
+								// proxy via its `editorQuery` prop binding below — this is
+								// the same pattern as `model.items`. We do not pass it as a
+								// separate prop because Svelte 5's mount() does not expose
+								// settable prop accessors, so we route through the proxy.
 								const mounted = mount(MentionDropdown, {
 									target: document.body,
-									props: { model: dropdownState }
+									props: {
+										model: dropdownState,
+										get editorQuery() {
+											return dropdownState.editorQuery;
+										},
+										onSearch
+									}
 								});
-								component = mounted as object;
+								mountedDropdown = mounted as object;
 								exports = mounted as unknown as DropdownExports;
 							},
 							onUpdate(renderProps) {
@@ -208,9 +274,16 @@ onMount(() => {
 								return exports?.onKeyDown(event) ?? false;
 							},
 							onExit() {
-								if (component) {
+								// Cancel any pending debounce so a closed dropdown's trailing
-									unmount(component);
+								// runSearch cannot fire against the *next* dropdown's state.
-									component = null;
+								// The hoisted `cancelPendingSearch` would be overwritten by
+								// the next render()'s onStart before the trailing call fires,
+								// so we cancel locally via the closure-scoped debouncedSearch.
+								// Felix #1 on PR #629.
+								debouncedSearch.cancel();
+								if (mountedDropdown) {
+									unmount(mountedDropdown);
+									mountedDropdown = null;
 									exports = null;
 								}
 							}
@@ -253,7 +326,15 @@ onMount(() => {
 });
 
 onDestroy(() => {
+	cancelPendingSearch?.();
 	editor?.destroy();
+	// Tiptap suggestion onExit usually unmounts the dropdown, but if the host
+	// component is destroyed while a suggestion is active the dropdown can
+	// outlive the editor — clean it up explicitly.
+	if (mountedDropdown) {
+		unmount(mountedDropdown);
+		mountedDropdown = null;
+	}
 });
 
 // Keep the data-placeholder attribute in sync with actual emptiness so the

frontend/src/lib/shared/discussion/PersonMentionEditor.svelte.spec.ts

@@ -8,29 +8,45 @@
 import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page, userEvent } from 'vitest/browser';
-import PersonMentionEditorHost from './PersonMentionEditor.test-host.svelte';
+import { tick } from 'svelte';
+import PersonMentionEditorHost from './PersonMentionEditor.test-fixture.svelte';
 import type { components } from '$lib/generated/api';
 import { m } from '$lib/paraglide/messages.js';
+// Single source of truth for the debounce window — imported from the shared
+// module so the test cannot drift from production. Sara on PR #629 round 3.
+import { SEARCH_DEBOUNCE_MS } from './mentionConstants';
 
 type Person = components['schemas']['Person'];
 type PersonMention = components['schemas']['PersonMention'];
 
+/**
+ * Headroom above SEARCH_DEBOUNCE_MS for the debounce-window wait
+ * assertions in this file. 350 ms is calibrated against CI-runner jitter
+ * we observed pre-#629; dropping it below ~200 ms reintroduces flake.
+ * See PR #629 round-2 review comment #10935 (Sara).
+ */
+const POST_DEBOUNCE_SLACK_MS = 350;
+
 const AUGUSTE: Person = {
 	id: 'p-aug',
 	firstName: 'Auguste',
 	lastName: 'Raddatz',
 	displayName: 'Auguste Raddatz',
+	personType: 'PERSON',
+	familyMember: false,
 	birthYear: 1882,
 	deathYear: 1944
-} as unknown as Person;
+};
 
 const ANNA: Person = {
 	id: 'p-anna',
 	firstName: 'Anna',
 	lastName: 'Schmidt',
 	displayName: 'Anna Schmidt',
+	personType: 'PERSON',
+	familyMember: false,
 	birthYear: 1860
-} as unknown as Person;
+};
 
 function mockFetchWithPersons(persons: Person[] = [AUGUSTE, ANNA]) {
 	vi.stubGlobal(
@@ -125,6 +141,20 @@ describe('PersonMentionEditor — typeahead', () => {
 		});
 	});
 
+	it('appends &limit=5 to the fetch URL (defensive client-side cap, Markus on PR #629)', async () => {
+		const fetchMock = vi
+			.fn()
+			.mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([AUGUSTE]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@Aug');
+
+		await vi.waitFor(() => {
+			expect(fetchMock).toHaveBeenCalledWith(expect.stringContaining('limit=5'));
+		});
+	});
+
 	it('shows life dates next to the name in the dropdown', async () => {
 		mockFetchWithPersons();
 		renderHost();
@@ -142,8 +172,15 @@ describe('PersonMentionEditor — typeahead', () => {
 
 		await userEvent.type(page.getByRole('textbox'), '@xyz');
 
-		await vi.waitFor(async () => {
+		// The visible empty-state <p> (text-ink-3) shows the copy. The persistent
-			await expect.element(page.getByText('Keine Personen gefunden')).toBeInTheDocument();
+		// sr-only aria-live region also contains the same copy, so we scope to the
+		// visible element to avoid a multi-match resolution in expect.element.
+		await vi.waitFor(() => {
+			const visibleEmptyP = document.querySelector(
+				'[role="listbox"] p.text-ink-3'
+			) as HTMLElement | null;
+			expect(visibleEmptyP).not.toBeNull();
+			expect(visibleEmptyP!.textContent ?? '').toContain('Keine Personen gefunden');
 		});
 	});
 
@@ -161,6 +198,254 @@ describe('PersonMentionEditor — typeahead', () => {
 	});
 });
 
+// ─── AC-2/3: search input drives the person fetch (debounced) ───────────────
+
+describe('PersonMentionEditor — AC-2/3: search input drives fetch', () => {
+	it('editing the search input fires a debounced fetch with the new query', async () => {
+		const fetchMock = vi
+			.fn()
+			.mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([AUGUSTE]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		// Open the dropdown so the search input is reachable.
+		await userEvent.type(page.getByRole('textbox'), '@');
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('searchbox')).toBeVisible();
+		});
+
+		const fetchesBeforeSearch = fetchMock.mock.calls.length;
+
+		// `fill` simulates a single input event with the final value — sidesteps
+		// per-keystroke timing of userEvent.type so the test can deterministically
+		// assert that one input event collapses into one debounced fetch.
+		await page.getByRole('searchbox').fill('Walter');
+
+		await vi.waitFor(
+			() => {
+				expect(fetchMock).toHaveBeenCalledWith(expect.stringContaining('q=Walter'));
+			},
+			{ timeout: 1000 }
+		);
+
+		const fetchesAfterSearch = fetchMock.mock.calls.length - fetchesBeforeSearch;
+		expect(fetchesAfterSearch).toBe(1);
+	});
+
+	it('fires exactly one /api/persons fetch when the user searches for Walter (regression guard)', async () => {
+		// Regression guard: a previous version of PersonMentionEditor had a
+		// duplicated `items()` callback in the Tiptap suggestion config that
+		// fetched per-keystroke in addition to the debounced search-input fetch
+		// (Markus & Felix round-1). To catch that regression, we must NOT
+		// subtract any baseline — every fetch from render onwards counts.
+		// Sara on PR #629 round 3.
+		const fetchMock = vi
+			.fn()
+			.mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([AUGUSTE]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		// Open the dropdown, then drive the search input via fill() — sidesteps
+		// per-keystroke timing of userEvent.type that Sara flagged round 2.
+		await userEvent.type(page.getByRole('textbox'), '@');
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('searchbox')).toBeVisible();
+		});
+		await page.getByRole('searchbox').fill('Walter');
+
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		// No baseline subtraction — count ALL /api/persons fetches since render.
+		// If the legacy per-keystroke items() callback returns, typing `@` alone
+		// would already produce one fetch and `fill('Walter')` another, breaking
+		// this assertion.
+		const personsFetches = fetchMock.mock.calls.filter(
+			([url]) => typeof url === 'string' && url.startsWith('/api/persons')
+		);
+		expect(personsFetches.length).toBe(1);
+	});
+
+	it('clearing the search input clears the list without firing a fetch', async () => {
+		const fetchMock = vi
+			.fn()
+			.mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([AUGUSTE]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@Aug');
+		await vi.waitFor(async () => {
+			await expect.element(page.getByText('Auguste Raddatz')).toBeInTheDocument();
+		});
+
+		const fetchesBeforeClear = fetchMock.mock.calls.length;
+
+		await userEvent.clear(page.getByRole('searchbox'));
+
+		// Negative assertion: wait past the debounce window to confirm no
+		// trailing fetch was scheduled. Removing this wait would mask a
+		// re-introduction of the keystroke-driven items() fetch.
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		expect(fetchMock.mock.calls.length).toBe(fetchesBeforeClear);
+		await expect.element(page.getByText('Auguste Raddatz')).not.toBeInTheDocument();
+	});
+});
+
+// ─── Whitespace-only query (Elicit AC-4 ambiguity on PR #629) ───────────────
+
+describe('PersonMentionEditor — whitespace-only query', () => {
+	it('keeps the "Namen eingeben…" prompt and fires no fetch when @ is followed only by spaces', async () => {
+		const fetchMock = vi.fn().mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@   ');
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('searchbox')).toBeVisible();
+		});
+
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		// Scope to the visible empty-state <p> (text-ink-3) — the persistent
+		// sr-only aria-live region above contains the same copy.
+		const visibleEmptyP = document.querySelector(
+			'[role="listbox"] p.text-ink-3'
+		) as HTMLElement | null;
+		expect(visibleEmptyP).not.toBeNull();
+		expect(visibleEmptyP!.textContent ?? '').toContain(m.person_mention_search_prompt());
+		expect(fetchMock).not.toHaveBeenCalled();
+	});
+});
+
+// ─── Stale-response race (Sara on PR #629) ───────────────────────────────────
+
+describe('PersonMentionEditor — stale-response race', () => {
+	it('discards a stale response that resolves after the search has been cleared', async () => {
+		let resolveFetch!: (v: { ok: boolean; json: () => Promise<Person[]> }) => void;
+		const pendingResponse = new Promise<{ ok: boolean; json: () => Promise<Person[]> }>((r) => {
+			resolveFetch = r;
+		});
+		const fetchMock = vi.fn().mockReturnValue(pendingResponse);
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		// Open the dropdown and let the debounce fire so a fetch is in flight.
+		await userEvent.type(page.getByRole('textbox'), '@Aug');
+		await vi.waitFor(() => {
+			expect(fetchMock).toHaveBeenCalledWith(expect.stringContaining('/api/persons?q=Aug'));
+		});
+
+		// Clear the search input *before* the fetch resolves.
+		await userEvent.clear(page.getByRole('searchbox'));
+		await expect.element(page.getByRole('searchbox')).toHaveValue('');
+
+		// The stale fetch now resolves with persons. The dropdown must stay empty.
+		resolveFetch({ ok: true, json: () => Promise.resolve([AUGUSTE]) });
+		// Flush pending Svelte reactivity so any (non-)update from the stale
+		// fetch resolution has landed before we assert. expect.element already
+		// polls, so no fixed-timeout fallback is needed. Sara on PR #629 round 4.
+		await tick();
+
+		await expect.element(page.getByText('Auguste Raddatz')).not.toBeInTheDocument();
+	});
+});
+
+// ─── Server failure characterization (Sara #2 on PR #629) ───────────────────
+
+describe('PersonMentionEditor — server failure', () => {
+	it('on 500 response keeps the dropdown open with the empty-state copy (silent failure pinned; distinct error UX tracked separately)', async () => {
+		const fetchMock = vi
+			.fn()
+			.mockResolvedValue({ ok: false, status: 500, json: vi.fn().mockResolvedValue({}) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@Aug');
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		// Pins current silent-failure behaviour. The day someone implements a
+		// distinct error UX (toast / "Suche fehlgeschlagen" copy), this test
+		// goes red and forces them to update the assertion. Scope to the
+		// visible <p> (text-ink-3) — the persistent sr-only live region
+		// above contains the same copy.
+		const visibleEmptyP = document.querySelector(
+			'[role="listbox"] p.text-ink-3'
+		) as HTMLElement | null;
+		expect(visibleEmptyP).not.toBeNull();
+		expect(visibleEmptyP!.textContent ?? '').toContain(m.person_mention_popup_empty());
+	});
+
+	it('on a fetch reject (network failure) keeps the dropdown open with the empty-state copy', async () => {
+		const fetchMock = vi.fn().mockRejectedValue(new TypeError('NetworkError'));
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@Aug');
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		const visibleEmptyP = document.querySelector(
+			'[role="listbox"] p.text-ink-3'
+		) as HTMLElement | null;
+		expect(visibleEmptyP).not.toBeNull();
+		expect(visibleEmptyP!.textContent ?? '').toContain(m.person_mention_popup_empty());
+	});
+});
+
+// ─── onExit cancels pending debounce (Felix #1 on PR #629) ───────────────────
+
+describe('PersonMentionEditor — onExit cancels pending debounce', () => {
+	it('cancels the pending debounced fetch when Escape closes the dropdown before the debounce fires', async () => {
+		const fetchMock = vi.fn().mockResolvedValue({ ok: true, json: vi.fn().mockResolvedValue([]) });
+		vi.stubGlobal('fetch', fetchMock);
+		renderHost();
+
+		// Open the dropdown by typing @ + a query in the editor.
+		await userEvent.type(page.getByRole('textbox'), '@A');
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('searchbox')).toBeVisible();
+		});
+
+		// Wait for any in-flight fetch from opening the dropdown to settle.
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+		const fetchesBeforeEscape = fetchMock.mock.calls.length;
+
+		// Trigger a new debounced search (queues runSearch after 150 ms), then
+		// immediately Escape *while focus is back in the editor* so Tiptap's
+		// suggestion-plugin Escape handler fires onExit before the debounce.
+		// Without onExit cancelling the pending debounce, runSearch executes
+		// against the now-unmounted dropdown's state.
+		await page.getByRole('searchbox').fill('Walter');
+		// Focus the editor so the Escape lands on Tiptap's suggestion handler.
+		(page.getByRole('textbox').element() as HTMLElement).focus();
+		await userEvent.keyboard('{Escape}');
+
+		// Wait past the debounce window. If onExit did not cancel the pending
+		// debounce, a fetch with q=Walter would still fire here.
+		await new Promise((r) => setTimeout(r, SEARCH_DEBOUNCE_MS + POST_DEBOUNCE_SLACK_MS));
+
+		const newFetches = fetchMock.mock.calls.slice(fetchesBeforeEscape);
+		const walterFetches = newFetches.filter(
+			([url]) => typeof url === 'string' && url.includes('q=Walter')
+		);
+		expect(walterFetches.length).toBe(0);
+	});
+});
+
+// ─── AC-1: search input prefilled with text typed after @ ───────────────────
+
+describe('PersonMentionEditor — AC-1: search input prefill', () => {
+	it('prefills the dropdown search input with the text typed after @', async () => {
+		mockFetchEmpty();
+		renderHost();
+
+		await userEvent.type(page.getByRole('textbox'), '@WdG');
+
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('searchbox')).toHaveValue('WdG');
+		});
+	});
+});
+
 // ─── AC-1: typed text becomes displayName, not DB name ───────────────────────
 
 describe('PersonMentionEditor — AC-1: typed text as displayName', () => {
@@ -229,6 +514,39 @@ describe('PersonMentionEditor — AC-1: typed text as displayName', () => {
 		});
 	});
 
+	it('clips the inserted displayName to MAX_QUERY_LENGTH=100 chars (Felix #3 on PR #629)', async () => {
+		// CWE-400 amplification: the dropdown clips its search input + mirror at
+		// 100 chars (Nora #1), but the host editor was passing the unclipped
+		// renderProps.query straight through to displayName — so a 105-char
+		// @-suffix in the editor could insert a 105-char displayName into the
+		// sidecar even though the dropdown only searched the first 100.
+		mockFetchWithPersons();
+		const host = renderHost();
+
+		// Type @ + 105 'A' chars in the contenteditable. The renderProps.query
+		// fed into the command callback derives from the editor text after `@`,
+		// not the dropdown's searchbox — so we must drive the editor.
+		await userEvent.type(page.getByRole('textbox'), '@' + 'A'.repeat(105));
+
+		// The mocked /api/persons returns AUGUSTE for any query — wait for it.
+		await vi.waitFor(async () => {
+			await expect.element(page.getByRole('option', { name: /Auguste Raddatz/ })).toBeVisible();
+		});
+
+		const option = (await page
+			.getByRole('option', { name: /Auguste Raddatz/ })
+			.element()) as HTMLElement;
+		option.dispatchEvent(new MouseEvent('mousedown', { bubbles: true, cancelable: true }));
+
+		await vi.waitFor(() => {
+			expect(host.snapshot.mentionedPersons).toHaveLength(1);
+			// Tight assertion: input is 105 chars, cap is exactly 100. Using
+			// `toHaveLength(100)` discriminates "clip works" from "clip works
+			// AND nothing weakened it to e.g. 95". Sara on PR #629 round 4.
+			expect(host.snapshot.mentionedPersons[0].displayName).toHaveLength(100);
+		});
+	});
+
 	it('does not duplicate the sidecar entry when the same person is selected twice', async () => {
 		mockFetchWithPersons();
 		const host = renderHost({

frontend/src/lib/shared/discussion/mentionConstants.ts

@@ -0,0 +1,10 @@
+/** Shared knobs for the @mention typeahead. Single source of truth for
+ *  the dropdown component and the host editor — keeps the layered length
+ *  cap and the debounce window consistent across both files. */
+export const MAX_QUERY_LENGTH = 100;
+export const SEARCH_DEBOUNCE_MS = 150;
+/** Defensive client-side cap on the result list. Single consumer today
+ *  (PersonMentionEditor), kept here for symmetry with the other limit
+ *  knobs so the @mention configuration lives in one place. Felix #1 on
+ *  PR #629 round 4. */
+export const SEARCH_RESULT_LIMIT = 5;

frontend/src/lib/shared/services/confirm.svelte.test.ts

@@ -1,7 +1,7 @@
 import { describe, it, expect, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page, userEvent } from 'vitest/browser';
-import TestHost from './confirm.test-host.svelte';
+import TestHost from './confirm.test-fixture.svelte';
 import type { ConfirmService } from './confirm.svelte.js';
 
 afterEach(cleanup);

frontend/src/lib/shared/utils/debounce.ts

@@ -1,12 +1,25 @@
 /**
  * Returns a debounced version of fn that delays invocation until after
- * `delay` ms have elapsed since the last call.
+ * `delay` ms have elapsed since the last call. The returned function
+ * exposes a `cancel()` method that DROPS (does not flush) the pending
+ * trailing invocation — essential when the host context (a destroyed
+ * component, an unmounted editor) shouldn't fire the trailing call.
  */
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-export function debounce<T extends (...args: any[]) => void>(fn: T, delay: number): T {
+export function debounce<T extends (...args: any[]) => void>(
-	let timer: ReturnType<typeof setTimeout>;
+	fn: T,
-	return ((...args: Parameters<T>) => {
+	delay: number
-		clearTimeout(timer);
+): T & { cancel: () => void } {
+	let timer: ReturnType<typeof setTimeout> | undefined;
+	const wrapped = ((...args: Parameters<T>) => {
+		if (timer !== undefined) clearTimeout(timer);
 		timer = setTimeout(() => fn(...args), delay);
-	}) as T;
+	}) as T & { cancel: () => void };
+	wrapped.cancel = () => {
+		if (timer !== undefined) {
+			clearTimeout(timer);
+			timer = undefined;
+		}
+	};
+	return wrapped;
 }

frontend/src/routes/admin/+layout.server.ts

@@ -1,6 +1,6 @@
 import { error } from '@sveltejs/kit';
 import { env } from '$env/dynamic/private';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 import type { components } from '$lib/generated/api';
 
@@ -34,16 +34,16 @@ export async function load({ fetch, locals }) {
 	]);
 
 	if (!usersResult.response.ok) {
-		const code = (usersResult.error as unknown as { code?: string })?.code;
+		throw error(usersResult.response.status, getErrorMessage(extractErrorCode(usersResult.error)));
-		throw error(usersResult.response.status, getErrorMessage(code));
 	}
 	if (!groupsResult.response.ok) {
-		const code = (groupsResult.error as unknown as { code?: string })?.code;
+		throw error(
-		throw error(groupsResult.response.status, getErrorMessage(code));
+			groupsResult.response.status,
+			getErrorMessage(extractErrorCode(groupsResult.error))
+		);
 	}
 	if (!tagsResult.response.ok) {
-		const code = (tagsResult.error as unknown as { code?: string })?.code;
+		throw error(tagsResult.response.status, getErrorMessage(extractErrorCode(tagsResult.error)));
-		throw error(tagsResult.response.status, getErrorMessage(code));
 	}
 
 	let inviteCount = 0;

frontend/src/routes/admin/groups/[id]/+page.server.ts

@@ -1,6 +1,6 @@
 import { error, fail, redirect } from '@sveltejs/kit';
 import type { PageServerLoad, Actions } from './$types';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export const load: PageServerLoad = async ({ params, parent }) => {
@@ -24,8 +24,9 @@ export const actions: Actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { error: getErrorMessage(code) });
+				error: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		return { success: true };
@@ -38,8 +39,9 @@ export const actions: Actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { error: getErrorMessage(code) });
+				error: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		throw redirect(303, '/admin/groups');

frontend/src/routes/admin/groups/[id]/page.server.spec.ts

@@ -7,7 +7,8 @@ const mockApi = {
 };
 
 vi.mock('$lib/shared/api.server', () => ({
-	createApiClient: () => mockApi
+	createApiClient: () => mockApi,
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
 }));
 
 beforeEach(() => vi.clearAllMocks());

frontend/src/routes/admin/groups/layout.server.spec.ts

@@ -1,7 +1,10 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest';
 import { load } from './+layout.server';
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 import { createApiClient } from '$lib/shared/api.server';
 

frontend/src/routes/admin/groups/new/+page.server.ts

@@ -1,6 +1,6 @@
 import { fail, redirect } from '@sveltejs/kit';
 import type { Actions } from './$types';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export const actions: Actions = {
@@ -16,8 +16,9 @@ export const actions: Actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { error: getErrorMessage(code) });
+				error: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		throw redirect(303, '/admin/groups');

frontend/src/routes/admin/invites/+page.server.ts

@@ -1,5 +1,5 @@
 import { fail } from '@sveltejs/kit';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 import type { Actions, PageServerLoad } from './$types';
 import type { components } from '$lib/generated/api';
@@ -25,8 +25,7 @@ export const load: PageServerLoad = async ({ url, fetch }) => {
 	let invites: InviteListItem[] = [];
 	let loadError: string | null = null;
 	if (!invitesResult.response.ok) {
-		const code = (invitesResult.error as unknown as { code?: string })?.code;
+		loadError = extractErrorCode(invitesResult.error) ?? 'INTERNAL_ERROR';
-		loadError = code ?? 'INTERNAL_ERROR';
 	} else {
 		invites = (invitesResult.data ?? []) as InviteListItem[];
 	}
@@ -34,8 +33,7 @@ export const load: PageServerLoad = async ({ url, fetch }) => {
 	let groups: UserGroup[] = [];
 	let groupsLoadError: string | null = null;
 	if (!groupsResult.response.ok) {
-		const code = (groupsResult.error as unknown as { code?: string })?.code;
+		groupsLoadError = extractErrorCode(groupsResult.error) ?? 'INTERNAL_ERROR';
-		groupsLoadError = code ?? 'INTERNAL_ERROR';
 	} else {
 		const raw = groupsResult.data ?? [];
 		groups = [...raw].sort((a, b) => a.name.localeCompare(b.name));
@@ -62,8 +60,9 @@ export const actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { createError: code ?? 'INTERNAL_ERROR' });
+				createError: extractErrorCode(result.error) ?? 'INTERNAL_ERROR'
+			});
 		}
 
 		return { created: result.data! as InviteListItem };
@@ -78,8 +77,9 @@ export const actions = {
 		const result = await api.DELETE('/api/invites/{id}', { params: { path: { id } } });
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { revokeError: code ?? 'INTERNAL_ERROR' });
+				revokeError: extractErrorCode(result.error) ?? 'INTERNAL_ERROR'
+			});
 		}
 
 		return { revoked: id };

frontend/src/routes/admin/layout.server.spec.ts

@@ -1,7 +1,10 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest';
 import { load } from './+layout.server';
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 import { createApiClient } from '$lib/shared/api.server';
 

frontend/src/routes/admin/ocr/+page.server.ts

@@ -1,6 +1,6 @@
 import { error } from '@sveltejs/kit';
 import type { PageServerLoad } from './$types';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export const load: PageServerLoad = async ({ fetch }) => {
@@ -8,8 +8,7 @@ export const load: PageServerLoad = async ({ fetch }) => {
 	const result = await api.GET('/api/ocr/training-info');
 
 	if (!result.response.ok) {
-		const code = (result.error as unknown as { code?: string })?.code;
+		throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-		throw error(result.response.status, getErrorMessage(code));
 	}
 
 	return { trainingInfo: result.data! };

frontend/src/routes/admin/ocr/[personId]/+page.server.ts

@@ -1,6 +1,6 @@
 import { error } from '@sveltejs/kit';
 import type { PageServerLoad } from './$types';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export const load: PageServerLoad = async ({ params, fetch }) => {
@@ -10,8 +10,7 @@ export const load: PageServerLoad = async ({ params, fetch }) => {
 	});
 
 	if (!result.response.ok) {
-		const code = (result.error as unknown as { code?: string })?.code;
+		throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-		throw error(result.response.status, getErrorMessage(code));
 	}
 
 	return { history: result.data!, personId: params.personId };

frontend/src/routes/admin/ocr/[personId]/page.server.spec.ts

@@ -3,7 +3,10 @@ import { load } from './+page.server';
 
 const mockApi = { GET: vi.fn() };
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: () => mockApi }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: () => mockApi,
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 beforeEach(() => vi.clearAllMocks());
 

frontend/src/routes/admin/ocr/global/+page.server.ts

@@ -1,6 +1,6 @@
 import { error } from '@sveltejs/kit';
 import type { PageServerLoad } from './$types';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export const load: PageServerLoad = async ({ fetch }) => {
@@ -8,8 +8,7 @@ export const load: PageServerLoad = async ({ fetch }) => {
 	const result = await api.GET('/api/ocr/training-info/global');
 
 	if (!result.response.ok) {
-		const code = (result.error as unknown as { code?: string })?.code;
+		throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-		throw error(result.response.status, getErrorMessage(code));
 	}
 
 	return { history: result.data! };

frontend/src/routes/admin/ocr/global/page.server.spec.ts

@@ -3,7 +3,10 @@ import { load } from './+page.server';
 
 const mockApi = { GET: vi.fn() };
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: () => mockApi }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: () => mockApi,
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 beforeEach(() => vi.clearAllMocks());
 

frontend/src/routes/admin/ocr/page.server.spec.ts

@@ -3,7 +3,10 @@ import { load } from './+page.server';
 
 const mockApi = { GET: vi.fn() };
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: () => mockApi }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: () => mockApi,
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 beforeEach(() => vi.clearAllMocks());
 

frontend/src/routes/admin/tags/[id]/+page.server.ts

@@ -1,6 +1,6 @@
 import { error, fail, redirect } from '@sveltejs/kit';
 import type { PageServerLoad, Actions } from './$types';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export const load: PageServerLoad = async ({ params, parent, url }) => {
@@ -25,8 +25,9 @@ export const actions: Actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { error: getErrorMessage(code) });
+				error: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		return { success: true };
@@ -43,8 +44,9 @@ export const actions: Actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { error: getErrorMessage(code) });
+				error: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		throw redirect(303, `/admin/tags/${result.data!.id}?merged=1`);
@@ -65,8 +67,9 @@ export const actions: Actions = {
 					});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { error: getErrorMessage(code) });
+				error: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		throw redirect(303, '/admin/tags');

frontend/src/routes/admin/tags/[id]/page.server.spec.ts

@@ -8,7 +8,8 @@ const mockApi = {
 };
 
 vi.mock('$lib/shared/api.server', () => ({
-	createApiClient: () => mockApi
+	createApiClient: () => mockApi,
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
 }));
 
 beforeEach(() => vi.clearAllMocks());

frontend/src/routes/admin/tags/layout.server.spec.ts

@@ -1,7 +1,10 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest';
 import { load } from './+layout.server';
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 import { createApiClient } from '$lib/shared/api.server';
 

frontend/src/routes/admin/users/[id]/+page.server.ts

@@ -1,6 +1,6 @@
 import { error, fail, redirect } from '@sveltejs/kit';
 import type { PageServerLoad, Actions } from './$types';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 import type { components } from '$lib/generated/api';
 
@@ -55,8 +55,9 @@ export const actions: Actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { error: getErrorMessage(code) });
+				error: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		return { success: true };
@@ -69,8 +70,9 @@ export const actions: Actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { error: getErrorMessage(code) });
+				error: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		throw redirect(303, '/admin/users');

frontend/src/routes/admin/users/[id]/page.server.spec.ts

@@ -4,7 +4,10 @@ vi.mock('$env/dynamic/private', () => ({
 	env: { API_INTERNAL_URL: 'http://localhost:8080' }
 }));
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 import { load, actions } from './+page.server';
 import { createApiClient } from '$lib/shared/api.server';

frontend/src/routes/admin/users/layout.server.spec.ts

@@ -1,7 +1,10 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest';
 import { load } from './+layout.server';
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 import { createApiClient } from '$lib/shared/api.server';
 

frontend/src/routes/admin/users/new/+page.server.ts

@@ -1,6 +1,6 @@
 import { error, fail, redirect } from '@sveltejs/kit';
 import type { PageServerLoad, Actions } from './$types';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export const load: PageServerLoad = async ({ fetch, locals }) => {
@@ -35,8 +35,9 @@ export const actions: Actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { error: getErrorMessage(code) });
+				error: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		throw redirect(303, '/admin/users');

frontend/src/routes/aktivitaeten/page.server.spec.ts

@@ -8,7 +8,8 @@ const mockApi = {
 };
 
 vi.mock('$lib/shared/api.server', () => ({
-	createApiClient: () => mockApi
+	createApiClient: () => mockApi,
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
 }));
 
 function buildUrl(search = ''): URL {

frontend/src/routes/briefwechsel/+page.server.ts

@@ -1,6 +1,6 @@
 import { error } from '@sveltejs/kit';
 import type { components } from '$lib/generated/api';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export async function load({ url, fetch, locals }) {
@@ -39,8 +39,7 @@ export async function load({ url, fetch, locals }) {
 				})
 				.then((result) => {
 					if (!result.response.ok) {
-						const code = (result.error as unknown as { code?: string })?.code;
+						throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-						throw error(result.response.status, getErrorMessage(code));
 					}
 					documents = result.data ?? [];
 				})
@@ -49,8 +48,7 @@ export async function load({ url, fetch, locals }) {
 		requests.push(
 			api.GET('/api/persons/{id}', { params: { path: { id: senderId } } }).then((result) => {
 				if (!result.response.ok) {
-					const code = (result.error as unknown as { code?: string })?.code;
+					throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-					throw error(result.response.status, getErrorMessage(code));
 				}
 				const p = result.data as { displayName: string } | undefined;
 				if (p) senderName = p.displayName;
@@ -62,8 +60,7 @@ export async function load({ url, fetch, locals }) {
 		requests.push(
 			api.GET('/api/persons/{id}', { params: { path: { id: receiverId } } }).then((result) => {
 				if (!result.response.ok) {
-					const code = (result.error as unknown as { code?: string })?.code;
+					throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-					throw error(result.response.status, getErrorMessage(code));
 				}
 				const p = result.data as { displayName: string } | undefined;
 				if (p) receiverName = p.displayName;

frontend/src/routes/briefwechsel/page.server.spec.ts

@@ -1,7 +1,10 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest';
 import { load } from './+page.server';
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 vi.mock('$lib/shared/errors', () => ({
 	getErrorMessage: (code: string) => code ?? 'Unknown error'
 }));

frontend/src/routes/documents/+page.server.ts

@@ -1,5 +1,5 @@
 import { redirect } from '@sveltejs/kit';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 import type { components } from '$lib/generated/api';
 
@@ -103,8 +103,7 @@ export async function load({ url, fetch }) {
 	}
 
 	const errorMessage: string | null = !result.response.ok
-		? (getErrorMessage((result.error as unknown as { code?: string })?.code) ??
+		? (getErrorMessage(extractErrorCode(result.error)) ?? 'Daten konnten nicht geladen werden.')
-			'Daten konnten nicht geladen werden.')
 		: null;
 
 	return {

frontend/src/routes/documents/[id]/+page.server.ts

@@ -1,5 +1,5 @@
 import { error, redirect } from '@sveltejs/kit';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 import { inferredRelationshipLabel } from '$lib/person/relationshipLabels';
 
@@ -17,8 +17,7 @@ export async function load({ params, fetch }) {
 	if (docResult.response.status === 401) throw redirect(302, '/login');
 
 	if (!docResult.response.ok) {
-		const code = (docResult.error as unknown as { code?: string })?.code;
+		throw error(docResult.response.status, getErrorMessage(extractErrorCode(docResult.error)));
-		throw error(docResult.response.status, getErrorMessage(code));
 	}
 
 	const document = docResult.data!;

frontend/src/routes/documents/[id]/edit/+page.server.ts

@@ -1,6 +1,6 @@
 import { error, fail, redirect } from '@sveltejs/kit';
 import { env } from '$env/dynamic/private';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { parseBackendError, getErrorMessage } from '$lib/shared/errors';
 
 export async function load({
@@ -30,8 +30,7 @@ export async function load({
 	]);
 
 	if (!docResult.response.ok) {
-		const code = (docResult.error as unknown as { code?: string })?.code;
+		throw error(docResult.response.status, getErrorMessage(extractErrorCode(docResult.error)));
-		throw error(docResult.response.status, getErrorMessage(code));
 	}
 	if (!personsResult.response.ok) {
 		throw error(personsResult.response.status, getErrorMessage('INTERNAL_ERROR'));
@@ -76,8 +75,9 @@ export const actions = {
 		// Fetch current document to preserve all existing fields
 		const docResult = await api.GET('/api/documents/{id}', { params: { path: { id: params.id } } });
 		if (!docResult.response.ok) {
-			const code = (docResult.error as unknown as { code?: string })?.code;
+			return fail(docResult.response.status, {
-			return fail(docResult.response.status, { error: getErrorMessage(code) });
+				error: getErrorMessage(extractErrorCode(docResult.error))
+			});
 		}
 
 		const doc = docResult.data!;

frontend/src/routes/documents/[id]/page.server.spec.ts

@@ -1,6 +1,9 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest';
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 vi.mock('$env/dynamic/private', () => ({ env: { API_INTERNAL_URL: 'http://test-backend:8080' } }));
 
 import { load } from './+page.server';

frontend/src/routes/documents/page.server.spec.ts

@@ -1,6 +1,9 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest';
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 import { load } from './+page.server';
 import { createApiClient } from '$lib/shared/api.server';

frontend/src/routes/enrich/[id]/+page.server.ts

@@ -1,6 +1,6 @@
 import { error, redirect } from '@sveltejs/kit';
 import { env } from '$env/dynamic/private';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage, parseBackendError } from '$lib/shared/errors';
 
 export async function load({
@@ -31,8 +31,7 @@ export async function load({
 	]);
 
 	if (!docResult.response.ok) {
-		const code = (docResult.error as unknown as { code?: string })?.code;
+		throw error(docResult.response.status, getErrorMessage(extractErrorCode(docResult.error)));
-		throw error(docResult.response.status, getErrorMessage(code));
 	}
 
 	const incompleteCount = countResult.response.ok ? (countResult.data?.count ?? 0) : 0;

frontend/src/routes/geschichten/+page.server.ts

@@ -1,5 +1,5 @@
 import { error } from '@sveltejs/kit';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 import type { components } from '$lib/generated/api';
 import type { PageServerLoad } from './$types';
@@ -25,8 +25,7 @@ export const load: PageServerLoad = async ({ url, fetch }) => {
 	]);
 
 	if (!listResult.response.ok) {
-		const code = (listResult.error as unknown as { code?: string })?.code;
+		throw error(listResult.response.status, getErrorMessage(extractErrorCode(listResult.error)));
-		throw error(listResult.response.status, getErrorMessage(code));
 	}
 
 	const personFilters = personResults

frontend/src/routes/geschichten/[id]/+page.server.ts

@@ -1,5 +1,5 @@
 import { error } from '@sveltejs/kit';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 import type { PageServerLoad } from './$types';
 
@@ -9,8 +9,7 @@ export const load: PageServerLoad = async ({ params, fetch }) => {
 		params: { path: { id: params.id } }
 	});
 	if (!result.response.ok) {
-		const code = (result.error as unknown as { code?: string })?.code;
+		throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-		throw error(result.response.status, getErrorMessage(code));
 	}
 	return { geschichte: result.data! };
 };

frontend/src/routes/geschichten/[id]/edit/+page.server.ts

@@ -1,5 +1,5 @@
 import { error, redirect } from '@sveltejs/kit';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 import type { PageServerLoad } from './$types';
 
@@ -13,8 +13,7 @@ export const load: PageServerLoad = async ({ params, fetch, parent }) => {
 		params: { path: { id: params.id } }
 	});
 	if (!result.response.ok) {
-		const code = (result.error as unknown as { code?: string })?.code;
+		throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-		throw error(result.response.status, getErrorMessage(code));
 	}
 	return { geschichte: result.data! };
 };

frontend/src/routes/page.server.spec.ts

@@ -1,6 +1,9 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest';
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 import { load } from './+page.server';
 import { createApiClient } from '$lib/shared/api.server';

frontend/src/routes/persons/[id]/+page.server.ts

@@ -1,5 +1,5 @@
 import { error } from '@sveltejs/kit';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export async function load({ params, fetch, locals }) {
@@ -32,8 +32,10 @@ export async function load({ params, fetch, locals }) {
 	]);
 
 	if (!personResult.response.ok) {
-		const code = (personResult.error as unknown as { code?: string })?.code;
+		throw error(
-		throw error(personResult.response.status, getErrorMessage(code));
+			personResult.response.status,
+			getErrorMessage(extractErrorCode(personResult.error))
+		);
 	}
 
 	return {

frontend/src/routes/persons/[id]/edit/+page.server.ts

@@ -1,5 +1,5 @@
 import { error, fail, redirect } from '@sveltejs/kit';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 import {
 	normalizePersonType,
@@ -25,8 +25,7 @@ export async function load({ params, fetch, locals }) {
 	]);
 
 	if (!result.response.ok) {
-		const code = (result.error as unknown as { code?: string })?.code;
+		throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-		throw error(result.response.status, getErrorMessage(code));
 	}
 
 	const person = result.data!;
@@ -74,8 +73,9 @@ export const actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { updateError: getErrorMessage(code) });
+				updateError: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		throw redirect(303, `/persons/${params.id}`);
@@ -100,8 +100,9 @@ export const actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { mergeError: getErrorMessage(code) });
+				mergeError: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		throw redirect(303, `/persons/${targetPersonId}`);
@@ -127,8 +128,9 @@ export const actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { aliasError: getErrorMessage(code) });
+				aliasError: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		return { aliasSuccess: true };
@@ -148,8 +150,9 @@ export const actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { aliasError: getErrorMessage(code) });
+				aliasError: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		return { aliasSuccess: true };
@@ -166,8 +169,9 @@ export const actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { relationshipError: getErrorMessage(code) });
+				relationshipError: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 		return { relationshipSuccess: true };
 	},
@@ -211,8 +215,9 @@ export const actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { relationshipError: getErrorMessage(code) });
+				relationshipError: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 		return { relationshipSuccess: true };
 	},
@@ -230,8 +235,9 @@ export const actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { relationshipError: getErrorMessage(code) });
+				relationshipError: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 		return { relationshipSuccess: true };
 	}

frontend/src/routes/persons/[id]/page.server.spec.ts

@@ -1,7 +1,10 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest';
 import { load } from './+page.server';
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: vi.fn() }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: vi.fn(),
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 import { createApiClient } from '$lib/shared/api.server';
 

frontend/src/routes/persons/new/+page.server.ts

@@ -1,5 +1,5 @@
 import { error, fail, redirect } from '@sveltejs/kit';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 import {
 	normalizePersonType,
@@ -57,9 +57,8 @@ export const actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
 			return fail(result.response.status, {
-				error: getErrorMessage(code),
+				error: getErrorMessage(extractErrorCode(result.error)),
 				personType,
 				title,
 				firstName,

frontend/src/routes/profile/+page.server.ts

@@ -1,7 +1,7 @@
 import { fail } from '@sveltejs/kit';
 import { env } from '$env/dynamic/private';
 import type { PageServerLoad, Actions } from './$types';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 const apiBase = () => env.API_INTERNAL_URL || 'http://localhost:8080';
@@ -27,8 +27,9 @@ export const actions: Actions = {
 		const result = await api.PUT('/api/users/me', { body });
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { updateError: getErrorMessage(code) });
+				updateError: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		return { updateSuccess: true };
@@ -50,8 +51,9 @@ export const actions: Actions = {
 		});
 
 		if (!result.response.ok) {
-			const code = (result.error as unknown as { code?: string })?.code;
+			return fail(result.response.status, {
-			return fail(result.response.status, { passwordError: getErrorMessage(code) });
+				passwordError: getErrorMessage(extractErrorCode(result.error))
+			});
 		}
 
 		return { passwordSuccess: true };

frontend/src/routes/stammbaum/+page.server.ts

@@ -1,5 +1,5 @@
 import { error, redirect } from '@sveltejs/kit';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export async function load({ fetch }) {
@@ -9,8 +9,7 @@ export async function load({ fetch }) {
 	if (result.response.status === 401) throw redirect(302, '/login');
 
 	if (!result.response.ok) {
-		const code = (result.error as unknown as { code?: string })?.code;
+		throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-		throw error(result.response.status, getErrorMessage(code));
 	}
 
 	const network = result.data!;

frontend/src/routes/users/[id]/+page.server.ts

@@ -1,6 +1,6 @@
 import { error } from '@sveltejs/kit';
 import type { PageServerLoad } from './$types';
-import { createApiClient } from '$lib/shared/api.server';
+import { createApiClient, extractErrorCode } from '$lib/shared/api.server';
 import { getErrorMessage } from '$lib/shared/errors';
 
 export const load: PageServerLoad = async ({ params, fetch }) => {
@@ -8,8 +8,7 @@ export const load: PageServerLoad = async ({ params, fetch }) => {
 	const result = await api.GET('/api/users/{id}', { params: { path: { id: params.id } } });
 
 	if (!result.response.ok) {
-		const code = (result.error as unknown as { code?: string })?.code;
+		throw error(result.response.status, getErrorMessage(extractErrorCode(result.error)));
-		throw error(result.response.status, getErrorMessage(code));
 	}
 
 	return { profileUser: result.data! };

infra/observability/grafana/provisioning/dashboards/loki-logs.json

@@ -196,7 +196,7 @@
       },
       "targets": [
         {
-          "expr": "{job=\"$app\"} |= \"$search\" | logfmt",
+          "expr": "{job=\"$app\"} |= \"$search\" | json",
           "hide": false,
           "legendFormat": "",
           "refId": "A"

infra/observability/prometheus/prometheus.yml

@@ -20,7 +20,4 @@ scrape_configs:
   - job_name: ocr-service
     metrics_path: /metrics
     static_configs:
-      # TODO: remove or add prometheus-client to ocr-service.
-      # The Python OCR service does not currently expose Prometheus metrics.
-      # This target will show as DOWN until prometheus-client is added to ocr-service.
       - targets: ['ocr:8000']

ocr-service/main.py

@@ -2,6 +2,7 @@
 
 import asyncio
 import glob
+import inspect
 import io
 import json
 import logging
@@ -10,9 +11,11 @@ import re
 import shutil
 import subprocess
 import tempfile
+import time
 import zipfile
 from contextlib import asynccontextmanager
 from datetime import datetime, timezone
+from typing import Awaitable, Callable
 from urllib.parse import urlparse
 
 import httpx
@@ -20,8 +23,11 @@ import pypdfium2 as pdfium
 from fastapi import FastAPI, Form, Header, HTTPException, UploadFile
 from fastapi.responses import StreamingResponse
 from PIL import Image
+from prometheus_client import REGISTRY
+from prometheus_fastapi_instrumentator import Instrumentator
 
 from confidence import apply_confidence_markers, get_threshold
+from metrics import OcrMetrics, build_metrics
 from spell_check import correct_text, load_spell_checker
 from engines import kraken as kraken_engine
 from engines import surya as surya_engine
@@ -37,6 +43,12 @@ logger = logging.getLogger(__name__)
 
 _models_ready = False
 
+# One-shot import-time binding to the default REGISTRY. Tests that need a
+# clean counter state must monkeypatch `main.metrics` with a container built
+# from a fresh CollectorRegistry — rebinding through the registry directly
+# will not retarget the references stored in the OcrMetrics dataclass.
+metrics: OcrMetrics = build_metrics(REGISTRY)
+
 ALLOWED_PDF_HOSTS = set(
     h.strip() for h in os.getenv("ALLOWED_PDF_HOSTS", "minio,localhost,127.0.0.1").split(",")
 )
@@ -44,6 +56,42 @@ ALLOWED_PDF_HOSTS = set(
 _SPELL_CHECK_SCRIPT_TYPES = {"HANDWRITING_KURRENT", "HANDWRITING_LATIN"}
 
 
+async def _record_training(
+    runner: Callable[[], Awaitable[dict] | dict],
+    kind: str,
+) -> dict:
+    """Run a training callable and record outcome + accuracy metrics.
+
+    Wraps the per-endpoint try/except + outcome counter + accuracy gauge
+    block that used to be repeated at /train, /train-sender, and /segtrain.
+    The runner returns a dict with at least an `accuracy` key; if its value
+    is None, the gauge is left at its default.
+    """
+    try:
+        result = runner()
+        if inspect.isawaitable(result):
+            result = await result
+    except Exception:
+        metrics.ocr_training_runs_total.labels(kind=kind, outcome="error").inc()
+        raise
+    metrics.ocr_training_runs_total.labels(kind=kind, outcome="success").inc()
+    if result.get("accuracy") is not None:
+        metrics.ocr_model_accuracy.labels(kind=kind).set(result["accuracy"])
+    return result
+
+
+def _observe_block_words(words: list[dict], threshold: float) -> None:
+    """Record per-block word counts and below-threshold word counts.
+
+    Pre: `words` is non-empty. Caller checks for that — keeping the helper
+    branch-free makes the call sites read as a single line.
+    """
+    metrics.ocr_words_total.inc(len(words))
+    metrics.ocr_illegible_words_total.inc(
+        sum(1 for w in words if w["confidence"] < threshold)
+    )
+
+
 def _validate_url(url: str) -> None:
     """Validate that the PDF URL points to an allowed host (SSRF protection)."""
     parsed = urlparse(url)
@@ -63,6 +111,7 @@ async def lifespan(app: FastAPI):
     kraken_engine.load_models()
     load_spell_checker()
     _models_ready = True
+    metrics.ocr_models_ready.set(1)
     logger.info("Startup complete — ready to accept requests")
 
     yield
@@ -72,6 +121,28 @@ async def lifespan(app: FastAPI):
 
 app = FastAPI(title="Familienarchiv OCR Service", lifespan=lifespan)
 
+# /metrics is unauthenticated — relies on Docker-internal-network exposure
+# only (CWE-200 risk if `ports:` ever maps 8000 to host). See
+# docs/OBSERVABILITY.md §Internal-only endpoints for the Caddy block snippet.
+Instrumentator(excluded_handlers=["/health", "/metrics"]).instrument(app).expose(app)
+
+
+class MetricsPathFilter(logging.Filter):
+    """Drop uvicorn.access entries for /metrics and /health to keep logs focused."""
+
+    _SUPPRESSED_PATHS = {"/metrics", "/health"}
+
+    def filter(self, record: logging.LogRecord) -> bool:
+        # uvicorn.access formats as: '%s - "%s %s HTTP/%s" %d'
+        if record.args and len(record.args) >= 3:
+            path = record.args[2]
+            if isinstance(path, str) and path in self._SUPPRESSED_PATHS:
+                return False
+        return True
+
+
+logging.getLogger("uvicorn.access").addFilter(MetricsPathFilter())
+
 
 @app.get("/health")
 def health():
@@ -99,7 +170,9 @@ async def run_ocr(request: OcrRequest):
         del img
 
     script_type = request.scriptType.upper()
+    engine_name = "kraken" if script_type == "HANDWRITING_KURRENT" else "surya"
 
+    extract_started = time.monotonic()
     if script_type == "HANDWRITING_KURRENT":
         if not kraken_engine.is_available():
             raise HTTPException(
@@ -111,11 +184,18 @@ async def run_ocr(request: OcrRequest):
     else:
         # TYPEWRITER, HANDWRITING_LATIN, UNKNOWN — all use Surya
         blocks = await asyncio.to_thread(surya_engine.extract_blocks, images, request.language)
+    metrics.ocr_processing_seconds.labels(engine=engine_name).observe(
+        time.monotonic() - extract_started
+    )
+
+    metrics.ocr_jobs_total.labels(engine=engine_name, script_type=script_type).inc()
 
     threshold = get_threshold(script_type)
     for block in blocks:
-        if block.get("words"):
+        words = block.get("words") or []
-            block["text"] = apply_confidence_markers(block["words"], threshold)
+        if words:
+            _observe_block_words(words, threshold)
+            block["text"] = apply_confidence_markers(words, threshold)
         block.pop("words", None)
         if script_type in _SPELL_CHECK_SCRIPT_TYPES:
             block["text"] = correct_text(block["text"])
@@ -146,6 +226,9 @@ async def run_ocr_stream(request: OcrRequest):
         )
 
     engine = kraken_engine if use_kraken else surya_engine
+    engine_name = "kraken" if use_kraken else "surya"
+
+    metrics.ocr_jobs_total.labels(engine=engine_name, script_type=script_type).inc()
 
     if request.regions:
         # Guided mode: recognize only the user-drawn annotation regions
@@ -176,12 +259,15 @@ async def run_ocr_stream(request: OcrRequest):
                     image = await asyncio.to_thread(preprocess_page, image)
                     blocks = []
                     sender_path = request.senderModelPath if use_kraken else None
+                    engine_seconds = 0.0
                     for region in page_regions:
+                        region_started = time.monotonic()
                         text = await asyncio.to_thread(
                             engine.extract_region_text, image,
                             region.x, region.y, region.width, region.height,
                             sender_path,
                         )
+                        engine_seconds += time.monotonic() - region_started
                         if script_type in _SPELL_CHECK_SCRIPT_TYPES:
                             text = correct_text(text)
                         blocks.append({
@@ -195,7 +281,11 @@ async def run_ocr_stream(request: OcrRequest):
                             "annotationId": region.annotationId,
                         })
 
+                    metrics.ocr_processing_seconds.labels(engine=engine_name).observe(
+                        engine_seconds
+                    )
                     total_blocks += len(blocks)
+                    metrics.ocr_pages_total.labels(engine=engine_name).inc()
                     yield json.dumps({
                         "type": "page",
                         "pageNumber": page_idx,
@@ -205,6 +295,7 @@ async def run_ocr_stream(request: OcrRequest):
                 except Exception:
                     logger.exception("Guided OCR failed on page %d", page_idx)
                     skipped_pages += 1
+                    metrics.ocr_skipped_pages_total.inc()
                     yield json.dumps({
                         "type": "error",
                         "pageNumber": page_idx,
@@ -238,18 +329,25 @@ async def run_ocr_stream(request: OcrRequest):
                 yield json.dumps({"type": "preprocessing", "pageNumber": page_idx}) + "\n"
                 image = await asyncio.to_thread(preprocess_page, image)
                 sender_path = request.senderModelPath if use_kraken else None
+                page_started = time.monotonic()
                 blocks = await asyncio.to_thread(
                     engine.extract_page_blocks, image, page_idx, request.language, sender_path
                 )
+                metrics.ocr_processing_seconds.labels(engine=engine_name).observe(
+                    time.monotonic() - page_started
+                )
 
                 for block in blocks:
-                    if block.get("words"):
+                    words = block.get("words") or []
-                        block["text"] = apply_confidence_markers(block["words"], threshold)
+                    if words:
+                        _observe_block_words(words, threshold)
+                        block["text"] = apply_confidence_markers(words, threshold)
                     block.pop("words", None)
                     if script_type in _SPELL_CHECK_SCRIPT_TYPES:
                         block["text"] = correct_text(block["text"])
 
                 total_blocks += len(blocks)
+                metrics.ocr_pages_total.labels(engine=engine_name).inc()
                 yield json.dumps({
                     "type": "page",
                     "pageNumber": page_idx,
@@ -259,6 +357,7 @@ async def run_ocr_stream(request: OcrRequest):
             except Exception:
                 logger.exception("OCR failed on page %d", page_idx)
                 skipped_pages += 1
+                metrics.ocr_skipped_pages_total.inc()
                 yield json.dumps({
                     "type": "error",
                     "pageNumber": page_idx,
@@ -438,8 +537,7 @@ async def train_model(
 
             return {"loss": None, "accuracy": accuracy, "cer": cer, "epochs": epochs}
 
-    result = await asyncio.to_thread(_run_training)
+    return await _record_training(lambda: asyncio.to_thread(_run_training), kind="recognition")
-    return result
 
 
 @app.post("/train-sender")
@@ -518,8 +616,9 @@ async def train_sender_model(
 
             return {"loss": None, "accuracy": accuracy, "cer": cer, "epochs": epochs}
 
-    result = await asyncio.to_thread(_run_sender_training)
+    return await _record_training(
-    return result
+        lambda: asyncio.to_thread(_run_sender_training), kind="recognition"
+    )
 
 
 @app.post("/segtrain")
@@ -628,8 +727,7 @@ async def segtrain_model(
 
             return {"loss": None, "accuracy": accuracy, "cer": cer, "epochs": epochs}
 
-    result = await asyncio.to_thread(_run_segtrain)
+    return await _record_training(lambda: asyncio.to_thread(_run_segtrain), kind="segmentation")
-    return result
 
 
 async def _download_and_convert_pdf(url: str) -> list[Image.Image]:

ocr-service/metrics.py

@@ -0,0 +1,92 @@
+"""Prometheus metric definitions for the OCR service.
+
+`build_metrics(registry)` returns a fresh `OcrMetrics` instance bound to the
+given `CollectorRegistry`. Production code calls it once at module load with
+the default `REGISTRY`; tests pass a per-test `CollectorRegistry()` to keep
+counter values isolated between cases (decision #3 on issue #652).
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+from prometheus_client import CollectorRegistry, Counter, Gauge, Histogram
+
+
+@dataclass(frozen=True)
+class OcrMetrics:
+    """Container for every custom OCR metric.
+
+    Counters and gauges are immutable references to `prometheus_client`
+    instances. Mutating them (`.inc()`, `.observe()`, `.set()`) is safe;
+    rebinding the field on the dataclass is not — use `build_metrics` to get
+    a new container.
+    """
+
+    ocr_jobs_total: Counter
+    ocr_pages_total: Counter
+    ocr_skipped_pages_total: Counter
+    ocr_words_total: Counter
+    ocr_illegible_words_total: Counter
+    ocr_processing_seconds: Histogram
+    ocr_training_runs_total: Counter
+    ocr_model_accuracy: Gauge
+    ocr_models_ready: Gauge
+
+
+def build_metrics(registry: CollectorRegistry) -> OcrMetrics:
+    """Create one OcrMetrics instance bound to `registry`."""
+    return OcrMetrics(
+        ocr_jobs_total=Counter(
+            "ocr_jobs_total",
+            "Number of OCR jobs processed, labelled by engine and script type.",
+            ["engine", "script_type"],
+            registry=registry,
+        ),
+        ocr_pages_total=Counter(
+            "ocr_pages_total",
+            "Number of pages successfully OCR'd, labelled by engine.",
+            ["engine"],
+            registry=registry,
+        ),
+        ocr_skipped_pages_total=Counter(
+            "ocr_skipped_pages_total",
+            "Number of pages skipped because the OCR engine raised.",
+            registry=registry,
+        ),
+        ocr_words_total=Counter(
+            "ocr_words_total",
+            "Number of words recognized across all OCR blocks.",
+            registry=registry,
+        ),
+        ocr_illegible_words_total=Counter(
+            "ocr_illegible_words_total",
+            "Number of words below the confidence threshold "
+            "(replaced with [unleserlich]).",
+            registry=registry,
+        ),
+        ocr_processing_seconds=Histogram(
+            "ocr_processing_seconds",
+            "OCR processing time per page (streaming) or per document (non-streaming).",
+            ["engine"],
+            registry=registry,
+        ),
+        ocr_training_runs_total=Counter(
+            "ocr_training_runs_total",
+            "Number of training runs, labelled by kind (recognition|segmentation) "
+            "and outcome (success|error).",
+            ["kind", "outcome"],
+            registry=registry,
+        ),
+        ocr_model_accuracy=Gauge(
+            "ocr_model_accuracy",
+            "Latest model accuracy reported by a successful training run.",
+            ["kind"],
+            registry=registry,
+        ),
+        ocr_models_ready=Gauge(
+            "ocr_models_ready",
+            "1 once the lifespan startup has finished loading models, 0 before.",
+            registry=registry,
+        ),
+    )

ocr-service/requirements.txt

@@ -10,3 +10,5 @@ pyvips>=2.2.0
 httpx==0.28.1
 pyspellchecker==0.9.0
 opencv-python-headless==4.11.0.86
+prometheus-fastapi-instrumentator==7.0.0
+prometheus-client==0.25.0

ocr-service/test_metrics.py

@@ -0,0 +1,638 @@
+"""Tests for Prometheus metrics exposed by the OCR service.
+
+Each test that asserts on a counter/gauge value uses a fresh CollectorRegistry
+(see decision #3 on issue #652) to keep the metrics isolated between tests.
+"""
+
+import contextlib
+import io
+import zipfile
+from unittest.mock import AsyncMock, patch
+
+import pytest
+from httpx import ASGITransport, AsyncClient
+from PIL import Image
+from prometheus_client import CollectorRegistry
+
+from main import app
+from metrics import build_metrics
+
+
+@contextlib.asynccontextmanager
+async def ocr_client(*, raise_app_exceptions: bool = True):
+    """Yield an AsyncClient with model-loaders patched and _models_ready forced on.
+
+    The shared setup for almost every metrics test: stub the heavy lifecycle
+    hooks (kraken_engine.load_models, load_spell_checker), flip the readiness
+    flag so request handlers do not 503, and restore it afterwards.
+    """
+    with patch("main.kraken_engine.load_models"), \
+         patch("main.load_spell_checker"):
+        transport = ASGITransport(app=app, raise_app_exceptions=raise_app_exceptions)
+        async with AsyncClient(transport=transport, base_url="http://test") as client:
+            import main as main_module
+            main_module._models_ready = True
+            try:
+                yield client
+            finally:
+                main_module._models_ready = False
+
+
+def _minimal_zip() -> bytes:
+    """Return a ZIP containing one fake .xml so endpoint validation passes."""
+    buf = io.BytesIO()
+    with zipfile.ZipFile(buf, "w") as zf:
+        zf.writestr("page_01.xml", "<PcGts/>")
+    return buf.getvalue()
+
+
+def _fake_training_result(accuracy: float = 0.91) -> dict:
+    return {"loss": None, "accuracy": accuracy, "cer": round(1 - accuracy, 4), "epochs": 5}
+
+
+@pytest.fixture
+def fresh_metrics(monkeypatch):
+    """Replace the module-level `main.metrics` with one bound to a fresh registry."""
+    registry = CollectorRegistry()
+    test_metrics = build_metrics(registry)
+    monkeypatch.setattr("main.metrics", test_metrics)
+    return test_metrics
+
+
+@pytest.mark.asyncio
+async def test_metrics_endpoint_returns_200():
+    """`GET /metrics` returns 200 with Prometheus exposition content.
+
+    Uses the global REGISTRY by design — does NOT take the `fresh_metrics` fixture.
+    The `/metrics` endpoint is wired by `prometheus-fastapi-instrumentator`, which
+    binds to the default REGISTRY at app-construction time; swapping `main.metrics`
+    via the fixture would not redirect what `/metrics` exposes. This test only
+    asserts response shape (status code + content-type substring), not numeric
+    counter values, so cross-test state leakage cannot affect it.
+    """
+    with patch("main.kraken_engine.load_models"), \
+         patch("main.load_spell_checker"):
+        async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as client:
+            response = await client.get("/metrics")
+
+    assert response.status_code == 200
+    assert "text/plain" in response.headers.get("content-type", "")
+
+
+@pytest.mark.asyncio
+async def test_metrics_includes_http_request_metrics_after_ocr_call():
+    """After a request to /ocr, `/metrics` exposes auto-instrumented http_* metrics.
+
+    Uses the global REGISTRY by design — does NOT take the `fresh_metrics` fixture.
+    The `http_requests_total` / `http_request_duration_seconds` metrics live on
+    the instrumentator's default REGISTRY (not on `main.metrics`), so a fresh
+    CollectorRegistry would never see them. This test only asserts response shape
+    (substring presence in the exposition body), not numeric counter values, so
+    cross-test state leakage cannot affect it.
+    """
+    mock_images = [Image.new("RGB", (100, 100))]
+    mock_blocks = [{"pageNumber": 1, "x": 0.0, "y": 0.0, "width": 1.0, "height": 1.0,
+                    "polygon": None, "text": "hi", "words": []}]
+
+    with patch("main._download_and_convert_pdf", new_callable=AsyncMock, return_value=mock_images), \
+         patch("main.preprocess_page", side_effect=lambda img: img), \
+         patch("main.surya_engine.extract_blocks", return_value=mock_blocks):
+        async with ocr_client() as client:
+            ocr_response = await client.post("/ocr", json={
+                "pdfUrl": "http://minio/doc.pdf",
+                "scriptType": "TYPEWRITER",
+                "language": "de",
+            })
+            assert ocr_response.status_code == 200, ocr_response.text
+
+            metrics_response = await client.get("/metrics")
+
+    body = metrics_response.text
+    assert "http_requests_total" in body
+    assert "http_request_duration_seconds" in body
+
+
+def test_build_metrics_registers_all_custom_metrics_on_given_registry():
+    """`build_metrics` returns an OcrMetrics bound to the supplied registry."""
+    registry = CollectorRegistry()
+    metrics = build_metrics(registry)
+
+    metric_names = {m.name for m in registry.collect()}
+    expected = {
+        "ocr_jobs",
+        "ocr_pages",
+        "ocr_skipped_pages",
+        "ocr_words",
+        "ocr_illegible_words",
+        "ocr_processing_seconds",
+        "ocr_training_runs",
+        "ocr_model_accuracy",
+        "ocr_models_ready",
+    }
+    assert expected <= metric_names, f"missing: {expected - metric_names}"
+
+    # A second registry yields a separate container — no shared state.
+    other_metrics = build_metrics(CollectorRegistry())
+    assert metrics is not other_metrics
+
+
+async def _drive_ocr(client: AsyncClient, *, script_type: str) -> None:
+    """Helper — fires /ocr with a single mocked page and asserts a 200."""
+    response = await client.post("/ocr", json={
+        "pdfUrl": "http://minio/doc.pdf",
+        "scriptType": script_type,
+        "language": "de",
+    })
+    assert response.status_code == 200, response.text
+
+
+@pytest.mark.asyncio
+async def test_ocr_jobs_total_incremented_with_kraken_engine_label_for_kurrent(fresh_metrics):
+    """A /ocr call with HANDWRITING_KURRENT increments engine=kraken."""
+    mock_images = [Image.new("RGB", (100, 100))]
+    mock_blocks = [{"pageNumber": 1, "x": 0.0, "y": 0.0, "width": 1.0, "height": 1.0,
+                    "polygon": None, "text": "hi", "words": []}]
+
+    with patch("main.correct_text", side_effect=lambda t: t), \
+         patch("main._download_and_convert_pdf", new_callable=AsyncMock, return_value=mock_images), \
+         patch("main.preprocess_page", side_effect=lambda img: img), \
+         patch("main.kraken_engine.is_available", return_value=True), \
+         patch("main.kraken_engine.extract_blocks", return_value=mock_blocks):
+        async with ocr_client() as client:
+            await _drive_ocr(client, script_type="HANDWRITING_KURRENT")
+
+    value = fresh_metrics.ocr_jobs_total.labels(
+        engine="kraken", script_type="HANDWRITING_KURRENT"
+    )._value.get()
+    assert value == 1.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_jobs_total_incremented_with_surya_engine_label_for_typewriter(fresh_metrics):
+    """A /ocr call with TYPEWRITER increments engine=surya."""
+    mock_images = [Image.new("RGB", (100, 100))]
+    mock_blocks = [{"pageNumber": 1, "x": 0.0, "y": 0.0, "width": 1.0, "height": 1.0,
+                    "polygon": None, "text": "hi", "words": []}]
+
+    with patch("main._download_and_convert_pdf", new_callable=AsyncMock, return_value=mock_images), \
+         patch("main.preprocess_page", side_effect=lambda img: img), \
+         patch("main.surya_engine.extract_blocks", return_value=mock_blocks):
+        async with ocr_client() as client:
+            await _drive_ocr(client, script_type="TYPEWRITER")
+
+    value = fresh_metrics.ocr_jobs_total.labels(
+        engine="surya", script_type="TYPEWRITER"
+    )._value.get()
+    assert value == 1.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_pages_total_incremented_once_per_page_in_stream(fresh_metrics):
+    """The /ocr/stream generator increments ocr_pages_total per successful page."""
+    mock_images = [Image.new("RGB", (100, 100)) for _ in range(3)]
+    mock_blocks = [{"pageNumber": 1, "x": 0.0, "y": 0.0, "width": 1.0, "height": 1.0,
+                    "polygon": None, "text": "hi", "words": []}]
+
+    with patch("main._download_and_convert_pdf", new_callable=AsyncMock, return_value=mock_images), \
+         patch("main.preprocess_page", side_effect=lambda img: img), \
+         patch("main.surya_engine.extract_page_blocks", return_value=mock_blocks):
+        async with ocr_client() as client:
+            async with client.stream("POST", "/ocr/stream", json={
+                "pdfUrl": "http://minio/doc.pdf",
+                "scriptType": "TYPEWRITER",
+                "language": "de",
+            }) as response:
+                assert response.status_code == 200
+                # Drain the stream so all per-page increments fire.
+                async for _ in response.aiter_lines():
+                    pass
+
+    value = fresh_metrics.ocr_pages_total.labels(engine="surya")._value.get()
+    assert value == 3.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_skipped_pages_total_incremented_when_engine_raises_for_a_page(fresh_metrics):
+    """When the engine raises on a page, ocr_skipped_pages_total bumps and the stream finishes."""
+    mock_images = [Image.new("RGB", (100, 100)) for _ in range(2)]
+    good_blocks = [{"pageNumber": 1, "x": 0.0, "y": 0.0, "width": 1.0, "height": 1.0,
+                    "polygon": None, "text": "ok", "words": []}]
+
+    call_count = {"n": 0}
+
+    def extract_side_effect(*args, **kwargs):
+        call_count["n"] += 1
+        if call_count["n"] == 1:
+            raise RuntimeError("synthetic engine failure")
+        return good_blocks
+
+    with patch("main._download_and_convert_pdf", new_callable=AsyncMock, return_value=mock_images), \
+         patch("main.preprocess_page", side_effect=lambda img: img), \
+         patch("main.surya_engine.extract_page_blocks", side_effect=extract_side_effect):
+        async with ocr_client() as client:
+            async with client.stream("POST", "/ocr/stream", json={
+                "pdfUrl": "http://minio/doc.pdf",
+                "scriptType": "TYPEWRITER",
+                "language": "de",
+            }) as response:
+                assert response.status_code == 200
+                saw_error = False
+                async for line in response.aiter_lines():
+                    if line and '"type": "error"' in line:
+                        saw_error = True
+                assert saw_error
+
+    assert fresh_metrics.ocr_skipped_pages_total._value.get() == 1.0
+    # The second page still succeeds.
+    assert fresh_metrics.ocr_pages_total.labels(engine="surya")._value.get() == 1.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_words_and_illegible_words_total_sum_across_blocks(fresh_metrics):
+    """Counters reflect totals summed over every block in the request.
+
+    Threshold defaults to THRESHOLD_DEFAULT (0.3) for non-Kurrent scripts. Two
+    blocks: 3 words above + 2 words below threshold across blocks.
+    """
+    mock_images = [Image.new("RGB", (100, 100))]
+    mock_blocks = [
+        {"pageNumber": 1, "x": 0.0, "y": 0.0, "width": 1.0, "height": 1.0,
+         "polygon": None, "text": "ignored",
+         "words": [{"text": "Lieber", "confidence": 0.9},
+                   {"text": "Freund", "confidence": 0.1}]},
+        {"pageNumber": 1, "x": 0.0, "y": 0.0, "width": 1.0, "height": 1.0,
+         "polygon": None, "text": "ignored",
+         "words": [{"text": "Gruss", "confidence": 0.8},
+                   {"text": "verschmiert", "confidence": 0.05},
+                   {"text": "Karl", "confidence": 0.95}]},
+    ]
+
+    with patch("main._download_and_convert_pdf", new_callable=AsyncMock, return_value=mock_images), \
+         patch("main.preprocess_page", side_effect=lambda img: img), \
+         patch("main.surya_engine.extract_blocks", return_value=mock_blocks):
+        async with ocr_client() as client:
+            await _drive_ocr(client, script_type="TYPEWRITER")
+
+    assert fresh_metrics.ocr_words_total._value.get() == 5.0
+    assert fresh_metrics.ocr_illegible_words_total._value.get() == 2.0
+
+
+def _histogram_count_sum(histogram, **labels) -> tuple[float, float]:
+    """Read the per-label-set _count and _sum from a prometheus_client Histogram."""
+    child = histogram.labels(**labels)
+    return child._sum.get(), sum(b.get() for b in child._buckets)
+
+
+@pytest.mark.asyncio
+async def test_ocr_processing_seconds_histogram_observed_per_page_in_stream(fresh_metrics):
+    """The streaming generator observes ocr_processing_seconds once per page."""
+    mock_images = [Image.new("RGB", (100, 100)) for _ in range(2)]
+    mock_blocks = [{"pageNumber": 1, "x": 0.0, "y": 0.0, "width": 1.0, "height": 1.0,
+                    "polygon": None, "text": "ok", "words": []}]
+
+    with patch("main._download_and_convert_pdf", new_callable=AsyncMock, return_value=mock_images), \
+         patch("main.preprocess_page", side_effect=lambda img: img), \
+         patch("main.surya_engine.extract_page_blocks", return_value=mock_blocks):
+        async with ocr_client() as client:
+            async with client.stream("POST", "/ocr/stream", json={
+                "pdfUrl": "http://minio/doc.pdf",
+                "scriptType": "TYPEWRITER",
+                "language": "de",
+            }) as response:
+                assert response.status_code == 200
+                async for _ in response.aiter_lines():
+                    pass
+
+    sum_seconds, count = _histogram_count_sum(
+        fresh_metrics.ocr_processing_seconds, engine="surya"
+    )
+    assert count == 2.0
+    assert sum_seconds >= 0.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_training_runs_total_incremented_with_recognition_success_label(fresh_metrics):
+    """/train success increments ocr_training_runs_total{kind=recognition, outcome=success}."""
+    async def fake_to_thread(func, *args, **kwargs):
+        return _fake_training_result()
+
+    with patch("main.TRAINING_TOKEN", "secret-token"), \
+         patch("main._models_ready", True), \
+         patch("main.asyncio.to_thread", side_effect=fake_to_thread):
+        async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as client:
+            response = await client.post(
+                "/train",
+                files={"file": ("training.zip", _minimal_zip(), "application/zip")},
+                headers={"X-Training-Token": "secret-token"},
+            )
+
+    assert response.status_code == 200
+    assert fresh_metrics.ocr_training_runs_total.labels(
+        kind="recognition", outcome="success"
+    )._value.get() == 1.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_training_runs_total_incremented_with_recognition_error_label(fresh_metrics):
+    """When ketos exits non-zero, the error counter bumps and the exception propagates.
+
+    Uses the narrowest available seam — `subprocess.run` returning a failing
+    CompletedProcess — instead of stubbing the asyncio.to_thread boundary,
+    so the test exercises the real _run_training error path.
+    """
+    from subprocess import CompletedProcess
+
+    failing_proc = CompletedProcess(
+        args=["ketos"], returncode=1, stdout="", stderr="synthetic ketos failure"
+    )
+
+    with patch("main.TRAINING_TOKEN", "secret-token"), \
+         patch("main._models_ready", True), \
+         patch("main.subprocess.run", return_value=failing_proc):
+        transport = ASGITransport(app=app, raise_app_exceptions=False)
+        async with AsyncClient(transport=transport, base_url="http://test") as client:
+            response = await client.post(
+                "/train",
+                files={"file": ("training.zip", _minimal_zip(), "application/zip")},
+                headers={"X-Training-Token": "secret-token"},
+            )
+
+    assert response.status_code == 500
+    assert fresh_metrics.ocr_training_runs_total.labels(
+        kind="recognition", outcome="error"
+    )._value.get() == 1.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_training_runs_total_incremented_with_segmentation_success_label(fresh_metrics):
+    """/segtrain success increments ocr_training_runs_total{kind=segmentation, outcome=success}."""
+    async def fake_to_thread(func, *args, **kwargs):
+        return _fake_training_result(accuracy=0.83)
+
+    with patch("main.TRAINING_TOKEN", "secret-token"), \
+         patch("main._models_ready", True), \
+         patch("main.asyncio.to_thread", side_effect=fake_to_thread):
+        async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as client:
+            response = await client.post(
+                "/segtrain",
+                files={"file": ("training.zip", _minimal_zip(), "application/zip")},
+                headers={"X-Training-Token": "secret-token"},
+            )
+
+    assert response.status_code == 200
+    assert fresh_metrics.ocr_training_runs_total.labels(
+        kind="segmentation", outcome="success"
+    )._value.get() == 1.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_training_runs_total_incremented_with_recognition_success_label_for_train_sender(fresh_metrics):
+    """/train-sender success increments ocr_training_runs_total{kind=recognition, outcome=success}."""
+    async def fake_to_thread(func, *args, **kwargs):
+        return _fake_training_result()
+
+    with patch("main.TRAINING_TOKEN", "secret-token"), \
+         patch("main._models_ready", True), \
+         patch("main.asyncio.to_thread", side_effect=fake_to_thread):
+        async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as client:
+            response = await client.post(
+                "/train-sender",
+                files={"file": ("training.zip", _minimal_zip(), "application/zip")},
+                data={"output_model_path": "/app/models/sender_test.mlmodel"},
+                headers={"X-Training-Token": "secret-token"},
+            )
+
+    assert response.status_code == 200, response.text
+    assert fresh_metrics.ocr_training_runs_total.labels(
+        kind="recognition", outcome="success"
+    )._value.get() == 1.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_model_accuracy_gauge_stays_default_when_training_returns_no_accuracy(fresh_metrics):
+    """When the runner returns accuracy=None, ocr_model_accuracy must remain at its default 0."""
+    async def fake_to_thread(func, *args, **kwargs):
+        return {"loss": None, "accuracy": None, "cer": None, "epochs": 5}
+
+    with patch("main.TRAINING_TOKEN", "secret-token"), \
+         patch("main._models_ready", True), \
+         patch("main.asyncio.to_thread", side_effect=fake_to_thread):
+        async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as client:
+            response = await client.post(
+                "/train",
+                files={"file": ("training.zip", _minimal_zip(), "application/zip")},
+                headers={"X-Training-Token": "secret-token"},
+            )
+
+    assert response.status_code == 200
+    # Gauge was never .set() — accessing the label child still creates it with default 0.0.
+    assert fresh_metrics.ocr_model_accuracy.labels(
+        kind="recognition"
+    )._value.get() == 0.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_model_accuracy_gauge_set_per_kind_after_successful_training(fresh_metrics):
+    """After /train and /segtrain succeed, ocr_model_accuracy{kind=...} reflects the result."""
+    recognition_accuracy = 0.917
+    segmentation_accuracy = 0.834
+
+    async def fake_recognition_to_thread(func, *args, **kwargs):
+        return _fake_training_result(accuracy=recognition_accuracy)
+
+    async def fake_segmentation_to_thread(func, *args, **kwargs):
+        return _fake_training_result(accuracy=segmentation_accuracy)
+
+    with patch("main.TRAINING_TOKEN", "secret-token"), \
+         patch("main._models_ready", True):
+        async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as client:
+            with patch("main.asyncio.to_thread", side_effect=fake_recognition_to_thread):
+                rec_resp = await client.post(
+                    "/train",
+                    files={"file": ("training.zip", _minimal_zip(), "application/zip")},
+                    headers={"X-Training-Token": "secret-token"},
+                )
+            assert rec_resp.status_code == 200
+            with patch("main.asyncio.to_thread", side_effect=fake_segmentation_to_thread):
+                seg_resp = await client.post(
+                    "/segtrain",
+                    files={"file": ("training.zip", _minimal_zip(), "application/zip")},
+                    headers={"X-Training-Token": "secret-token"},
+                )
+            assert seg_resp.status_code == 200
+
+    assert fresh_metrics.ocr_model_accuracy.labels(kind="recognition")._value.get() == pytest.approx(recognition_accuracy)
+    assert fresh_metrics.ocr_model_accuracy.labels(kind="segmentation")._value.get() == pytest.approx(segmentation_accuracy)
+
+
+def test_ocr_models_ready_gauge_defaults_to_zero():
+    """A freshly-built OcrMetrics has ocr_models_ready=0 before lifespan runs."""
+    metrics = build_metrics(CollectorRegistry())
+    assert metrics.ocr_models_ready._value.get() == 0.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_models_ready_gauge_is_one_after_lifespan_startup(fresh_metrics):
+    """The lifespan flips ocr_models_ready to 1 once load_models / load_spell_checker return.
+
+    ASGITransport does not run lifespan by default, so the lifespan context
+    manager is driven directly to exercise the startup code path.
+    """
+    assert fresh_metrics.ocr_models_ready._value.get() == 0.0
+    with patch("main.kraken_engine.load_models"), \
+         patch("main.load_spell_checker"):
+        async with app.router.lifespan_context(app):
+            assert fresh_metrics.ocr_models_ready._value.get() == 1.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_processing_seconds_histogram_observed_per_page_in_guided_stream(fresh_metrics):
+    """The guided streaming generator observes ocr_processing_seconds once per page."""
+    mock_images = [Image.new("RGB", (100, 100)) for _ in range(2)]
+    regions = [
+        {"pageNumber": 1, "x": 0.0, "y": 0.0, "width": 0.5, "height": 0.5, "annotationId": "a1"},
+        {"pageNumber": 2, "x": 0.0, "y": 0.0, "width": 1.0, "height": 1.0, "annotationId": "a2"},
+    ]
+
+    with patch("main._download_and_convert_pdf", new_callable=AsyncMock, return_value=mock_images), \
+         patch("main.preprocess_page", side_effect=lambda img: img), \
+         patch("main.surya_engine.extract_region_text", return_value="text"):
+        async with ocr_client() as client:
+            async with client.stream("POST", "/ocr/stream", json={
+                "pdfUrl": "http://minio/doc.pdf",
+                "scriptType": "TYPEWRITER",
+                "language": "de",
+                "regions": regions,
+            }) as response:
+                assert response.status_code == 200
+                async for _ in response.aiter_lines():
+                    pass
+
+    sum_seconds, count = _histogram_count_sum(
+        fresh_metrics.ocr_processing_seconds, engine="surya"
+    )
+    assert count == 2.0
+    assert sum_seconds >= 0.0
+
+
+@pytest.mark.asyncio
+async def test_ocr_processing_seconds_histogram_excludes_spell_check_time_in_guided_stream(fresh_metrics):
+    """The guided observation must time engine work only, not the spell-check pass.
+
+    Wall-clock bound rather than a structural `patch("main.time.monotonic")`:
+    the patched attribute is the *global* `time.monotonic`, which httpx and
+    asyncio also consume — they exhaust the deterministic sequence before the
+    request reaches the engine loop. Bound is sized against the failure mode,
+    not the noise floor: spell-check sleeps 0.05s × 2 regions = 0.1s, so a
+    timer that accidentally wrapped `correct_text` would observe >= 0.1s. The
+    0.09s ceiling catches that bug while leaving ~90ms of slack for slow CI
+    runners (engine work is instantaneous under the mock).
+    """
+    mock_images = [Image.new("RGB", (100, 100))]
+    regions = [
+        {"pageNumber": 1, "x": 0.0, "y": 0.0, "width": 0.5, "height": 0.5, "annotationId": "a1"},
+        {"pageNumber": 1, "x": 0.5, "y": 0.0, "width": 0.5, "height": 0.5, "annotationId": "a2"},
+    ]
+
+    def slow_correct(text):
+        import time as _time
+        _time.sleep(0.05)
+        return text
+
+    with patch("main._download_and_convert_pdf", new_callable=AsyncMock, return_value=mock_images), \
+         patch("main.preprocess_page", side_effect=lambda img: img), \
+         patch("main.kraken_engine.is_available", return_value=True), \
+         patch("main.kraken_engine.extract_region_text", return_value="text"), \
+         patch("main.correct_text", side_effect=slow_correct):
+        async with ocr_client() as client:
+            async with client.stream("POST", "/ocr/stream", json={
+                "pdfUrl": "http://minio/doc.pdf",
+                "scriptType": "HANDWRITING_KURRENT",
+                "language": "de",
+                "regions": regions,
+            }) as response:
+                assert response.status_code == 200
+                async for _ in response.aiter_lines():
+                    pass
+
+    sum_seconds, _ = _histogram_count_sum(
+        fresh_metrics.ocr_processing_seconds, engine="kraken"
+    )
+    assert sum_seconds < 0.09, f"timing must exclude spell-check; got sum={sum_seconds}"
+
+
+@pytest.mark.asyncio
+async def test_ocr_jobs_total_not_incremented_when_pdf_download_fails_in_stream(fresh_metrics):
+    """If `_download_and_convert_pdf` raises, ocr_jobs_total is NOT incremented.
+
+    Mirrors the /ocr endpoint's semantics: the counter only records jobs that
+    actually started OCR work, not failed downloads.
+    """
+    async def fail_download(url):
+        raise RuntimeError("synthetic download failure")
+
+    with patch("main._download_and_convert_pdf", new=fail_download):
+        async with ocr_client(raise_app_exceptions=False) as client:
+            response = await client.post("/ocr/stream", json={
+                "pdfUrl": "http://minio/doc.pdf",
+                "scriptType": "TYPEWRITER",
+                "language": "de",
+            })
+
+    assert response.status_code == 500
+    assert fresh_metrics.ocr_jobs_total.labels(
+        engine="surya", script_type="TYPEWRITER"
+    )._value.get() == 0.0
+
+
+def test_uvicorn_access_log_filter_fails_open_on_short_or_missing_args():
+    """The filter must default-allow records when args is None or shorter than expected.
+
+    Locks in fail-open behavior: if uvicorn ever changes its format we keep
+    forwarding records to the handler rather than silently dropping logs.
+    """
+    import logging as _logging
+    from main import MetricsPathFilter
+
+    filt = MetricsPathFilter()
+    none_record = _logging.LogRecord(
+        name="uvicorn.access", level=_logging.INFO, pathname="", lineno=0,
+        msg="some message", args=None, exc_info=None,
+    )
+    short_record = _logging.LogRecord(
+        name="uvicorn.access", level=_logging.INFO, pathname="", lineno=0,
+        msg="%s %s", args=("a", "b"), exc_info=None,
+    )
+
+    assert filt.filter(none_record) is True
+    assert filt.filter(short_record) is True
+
+
+def test_uvicorn_access_log_filter_skips_metrics_path():
+    """The MetricsPathFilter drops uvicorn.access log records that target /metrics."""
+    import logging as _logging
+    from main import MetricsPathFilter
+
+    filt = MetricsPathFilter()
+    metrics_record = _logging.LogRecord(
+        name="uvicorn.access", level=_logging.INFO, pathname="", lineno=0,
+        msg='%s - "%s %s HTTP/%s" %d',
+        args=("127.0.0.1:1234", "GET", "/metrics", "1.1", 200),
+        exc_info=None,
+    )
+    health_record = _logging.LogRecord(
+        name="uvicorn.access", level=_logging.INFO, pathname="", lineno=0,
+        msg='%s - "%s %s HTTP/%s" %d',
+        args=("127.0.0.1:1234", "GET", "/health", "1.1", 200),
+        exc_info=None,
+    )
+    ocr_record = _logging.LogRecord(
+        name="uvicorn.access", level=_logging.INFO, pathname="", lineno=0,
+        msg='%s - "%s %s HTTP/%s" %d',
+        args=("127.0.0.1:1234", "POST", "/ocr", "1.1", 200),
+        exc_info=None,
+    )
+
+    assert filt.filter(metrics_record) is False
+    assert filt.filter(health_record) is False
+    assert filt.filter(ocr_record) is True