diff --git a/ocr-service/main.py b/ocr-service/main.py
index 31fd9cad..51cf737b 100644
--- a/ocr-service/main.py
+++ b/ocr-service/main.py
@@ -50,6 +50,18 @@ ALLOWED_PDF_HOSTS = set(
 _SPELL_CHECK_SCRIPT_TYPES = {"HANDWRITING_KURRENT", "HANDWRITING_LATIN"}
 
 
+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)
@@ -149,10 +161,7 @@ async def run_ocr(request: OcrRequest):
     for block in blocks:
         words = block.get("words") or []
         if words:
-            metrics.ocr_words_total.inc(len(words))
-            metrics.ocr_illegible_words_total.inc(
-                sum(1 for w in words if w["confidence"] < threshold)
-            )
+            _observe_block_words(words, threshold)
             block["text"] = apply_confidence_markers(words, threshold)
         block.pop("words", None)
         if script_type in _SPELL_CHECK_SCRIPT_TYPES:
@@ -298,10 +307,7 @@ async def run_ocr_stream(request: OcrRequest):
                 for block in blocks:
                     words = block.get("words") or []
                     if words:
-                        metrics.ocr_words_total.inc(len(words))
-                        metrics.ocr_illegible_words_total.inc(
-                            sum(1 for w in words if w["confidence"] < threshold)
-                        )
+                        _observe_block_words(words, threshold)
                         block["text"] = apply_confidence_markers(words, threshold)
                     block.pop("words", None)
                     if script_type in _SPELL_CHECK_SCRIPT_TYPES: