diff --git a/README.md b/README.md
index e522d2e..7fe9681 100644
--- a/README.md
+++ b/README.md
@@ -5,9 +5,32 @@ Microservice der Dateien aus Nextcloud (`Documents/THB/Studium/`) in Qdrant inde
 ## Endpoints
 
 - `POST /webhook` (Header `X-Webhook-Secret`): Nextcloud-Event-Empfang (`created` / `updated` / `deleted`).
-- `POST /bulk-import` (Header `X-Webhook-Secret`): Body `{"path": "..."}` → rekursiver Re-Index.
+- `POST /bulk-import` (Header `X-Webhook-Secret`): Body `{"path": "..."}` → rekursiver Re-Index. Bulk-Pipeline-Stages laufen mit Concurrency 4 (siehe `BULK_CONCURRENCY` in `app/bulk.py`).
 - `GET /health`: Liveness-Probe.
 
+### Webhook-Payload-Format
+
+Der Service erwartet ein vorgeformtes JSON. Nextcloud-Roh-Events werden **nicht** direkt akzeptiert — sie müssen via Flow-Webhook in dieses Schema übersetzt werden:
+
+```json
+{
+  "event_type": "created",
+  "file_path": "Documents/THB/Studium/2.Semester/Databases/DBS1.pdf",
+  "file_name": "DBS1.pdf"
+}
+```
+
+`event_type` ∈ `{"created", "updated", "deleted"}`. Auth via Header `X-Webhook-Secret`, der mit `WEBHOOK_SECRET` aus der Konfiguration übereinstimmen muss.
+
+Beispielaufruf:
+
+```bash
+curl -X POST http://localhost:8000/webhook \
+  -H "Content-Type: application/json" \
+  -H "X-Webhook-Secret: $WEBHOOK_SECRET" \
+  -d '{"event_type": "created", "file_path": "Documents/THB/Studium/2.Semester/Databases/DBS1.pdf", "file_name": "DBS1.pdf"}'
+```
+
 ## Erwartete Ordnerstruktur
 
 ```
@@ -43,3 +66,30 @@ uv run pytest -v
 ```
 
 Tests deckt Pure-Logic ab (Metadata-Parser, Chunker, Extractors, Auth, Pipeline-Orchestrierung mit gemockten externen Services). Keine Integration-Tests gegen echte Ollama/Qdrant/WebDAV-Instanzen.
+
+## Recovery-Runbook
+
+### Einbettungs-Modell oder -Dimension geändert
+
+Beim Boot crasht der Service mit `qdrant collection ... dimension mismatch`, falls die existierende Collection eine andere Vektor-Dimension hat als das aktuelle Embedding-Modell. Dies ist Absicht (Fail-Fast). Vorgehen:
+
+1. Collection in Qdrant manuell droppen:
+   ```bash
+   curl -X DELETE "$QDRANT_URL/collections/$QDRANT_COLLECTION"
+   ```
+2. Service neu starten — Lifespan legt die Collection mit der neuen Dimension an.
+3. Bulk-Import auf den Studium-Root anstoßen, um alle Inhalte neu zu indexieren:
+   ```bash
+   curl -X POST http://localhost:8000/bulk-import \
+     -H "Content-Type: application/json" \
+     -H "X-Webhook-Secret: $WEBHOOK_SECRET" \
+     -d '{"path": "Documents/THB/Studium"}'
+   ```
+
+### Webhook-Ausfall / fehlende In-Flight-Jobs nach Crash
+
+Der Service hat keinen persistenten Job-Store; In-Flight-`BackgroundTask`s gehen bei Crash verloren. Recovery erfolgt über den Bulk-Import-Endpoint auf den betroffenen Pfad (siehe oben).
+
+### Ein einzelnes File neu indexieren
+
+Webhook mit `event_type: "updated"` an `/webhook` POSTen — alte Chunks werden via `delete_by_filter(file_path)` entfernt, dann frisch indexiert.
diff --git a/app/bulk.py b/app/bulk.py
index ac4c3ae..3c7d2da 100644
--- a/app/bulk.py
+++ b/app/bulk.py
@@ -1,3 +1,4 @@
+import asyncio
 import logging
 import xml.etree.ElementTree as ET
 from pathlib import PurePosixPath
@@ -18,6 +19,17 @@ logger = logging.getLogger(__name__)
 router = APIRouter()
 
 
+# Limits parallel pipeline execution during a bulk import so we don't
+# saturate Ollama/WebDAV with thousands of concurrent requests.
+BULK_CONCURRENCY = 4
+_bulk_semaphore = asyncio.Semaphore(BULK_CONCURRENCY)
+
+
+async def _process_with_semaphore(file_path: str, event_type: EventType) -> None:
+    async with _bulk_semaphore:
+        await process_file(file_path, event_type)
+
+
 class BulkRequest(BaseModel):
     path: str = Field(min_length=1)
 
@@ -93,7 +105,7 @@ async def bulk_import(
         ext = PurePosixPath(f).suffix.lstrip(".").lower()
         if ext not in SUPPORTED_TYPES:
             continue
-        background.add_task(process_file, f, EventType.CREATED)
+        background.add_task(_process_with_semaphore, f, EventType.CREATED)
         dispatched += 1
 
     logger.info(
diff --git a/app/ingest/pipeline.py b/app/ingest/pipeline.py
index b78643d..73bfa2e 100644
--- a/app/ingest/pipeline.py
+++ b/app/ingest/pipeline.py
@@ -1,4 +1,5 @@
 import logging
+import time
 from datetime import datetime, timezone
 from functools import lru_cache
 from pathlib import PurePosixPath
@@ -49,6 +50,7 @@ async def process_file(file_path: str, event_type: EventType) -> None:
         )
         return
 
+    t0 = time.perf_counter()
     try:
         data = await download_file(
             settings.nextcloud_webdav_url,
@@ -59,7 +61,13 @@ async def process_file(file_path: str, event_type: EventType) -> None:
     except Exception as exc:
         logger.exception("download failed", extra={"event": "download_failed", "file": file_path, "error": str(exc)})
         return
+    download_ms = int((time.perf_counter() - t0) * 1000)
+    logger.info(
+        "download ok",
+        extra={"event": "download", "status": "ok", "file": file_path, "duration_ms": download_ms, "bytes": len(data)},
+    )
 
+    t0 = time.perf_counter()
     try:
         pages = extract(data, extension, filename=PurePosixPath(file_path).name)
     except UnsupportedFileType:
@@ -68,6 +76,11 @@ async def process_file(file_path: str, event_type: EventType) -> None:
     except Exception as exc:
         logger.exception("extract failed", extra={"event": "extract_failed", "file": file_path, "error": str(exc)})
         return
+    extract_ms = int((time.perf_counter() - t0) * 1000)
+    logger.info(
+        "extract ok",
+        extra={"event": "extract", "status": "ok", "file": file_path, "duration_ms": extract_ms, "pages": len(pages)},
+    )
 
     chunks: list[tuple[str, int, int]] = []  # (text, page, chunk_index)
     chunk_index = 0
@@ -87,11 +100,17 @@ async def process_file(file_path: str, event_type: EventType) -> None:
         delete_by_path(_qdrant_client(), settings.qdrant_collection, file_path)
         return
 
+    t0 = time.perf_counter()
     try:
         vectors = await embed_texts([c[0] for c in chunks], model=settings.ollama_embed_model)
     except Exception as exc:
         logger.exception("embed failed", extra={"event": "embed_failed", "file": file_path, "error": str(exc)})
         return
+    embed_ms = int((time.perf_counter() - t0) * 1000)
+    logger.info(
+        "embed ok",
+        extra={"event": "embed", "status": "ok", "file": file_path, "duration_ms": embed_ms, "chunks": len(vectors)},
+    )
 
     if len(vectors) != len(chunks):
         logger.error(
@@ -121,11 +140,19 @@ async def process_file(file_path: str, event_type: EventType) -> None:
         for vec, (text, page_num, idx) in zip(vectors, chunks)
     ]
 
+    t0 = time.perf_counter()
     qdrant = _qdrant_client()
     delete_by_path(qdrant, settings.qdrant_collection, file_path)
     upsert_chunks(qdrant, settings.qdrant_collection, points)
+    qdrant_ms = int((time.perf_counter() - t0) * 1000)
 
     logger.info(
         "ingested",
-        extra={"event": "ingest_done", "file": file_path, "chunks": len(points)},
+        extra={
+            "event": "ingest_done",
+            "status": "ok",
+            "file": file_path,
+            "chunks": len(points),
+            "duration_ms": qdrant_ms,
+        },
     )