diff --git a/CLAUDE.md b/CLAUDE.md
index 5a83c6e8..6691aa34 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -274,6 +274,31 @@ Back button pattern — use the shared `<BackButton>` component from `$lib/share
 
 → See [docs/DEPLOYMENT.md](./docs/DEPLOYMENT.md)
 
+### Observability stack (separate compose file)
+
+Run via `docker-compose.observability.yml` — requires the main stack to be running first. Full setup procedure: [docs/DEPLOYMENT.md §4](./docs/DEPLOYMENT.md#4-logs--observability).
+
+| Service | Container | Default Port | Purpose |
+|---------|-----------|-------------|---------|
+| Grafana | `obs-grafana` | 3003 | Metrics / logs / traces dashboard |
+| Prometheus | `obs-prometheus` | 9090 (dev only — `127.0.0.1` bound) | Metrics store |
+| Loki | `obs-loki` | — (internal) | Log store |
+| Tempo | `obs-tempo` | — (internal) | Trace store |
+| GlitchTip | `obs-glitchtip` | 3002 | Error tracking (Sentry-compatible) |
+
+### Observability env vars
+
+| Variable | Purpose |
+|----------|---------|
+| `PORT_GRAFANA` | Host port for Grafana UI (default: `3003`) |
+| `PORT_GLITCHTIP` | Host port for GlitchTip UI (default: `3002`) |
+| `PORT_PROMETHEUS` | Host port for Prometheus UI (default: `9090`) |
+| `GRAFANA_ADMIN_PASSWORD` | Grafana `admin` login password |
+| `GLITCHTIP_SECRET_KEY` | Django secret key for GlitchTip — generate with `python3 -c "import secrets; print(secrets.token_hex(32))"` |
+| `GLITCHTIP_DOMAIN` | Public-facing base URL for GlitchTip (email links, CORS) |
+| `SENTRY_DSN` | GlitchTip/Sentry DSN for the backend (Spring Boot) — leave empty to disable |
+| `VITE_SENTRY_DSN` | GlitchTip/Sentry DSN for the frontend (SvelteKit) — injected at build time via Vite |
+
 ## API Testing
 
 HTTP test files are in `backend/api_tests/` for use with the VS Code REST Client extension.