diff --git a/python/vector/vector_service.py b/python/vector/vector_service.py
index b563a9a..006a81d 100644
--- a/python/vector/vector_service.py
+++ b/python/vector/vector_service.py
@@ -1,6 +1,10 @@
 #!/usr/bin/env python3
 
 import json
+import logging
+from logging.handlers import RotatingFileHandler
+import threading
+import time
 from pathlib import Path
 from typing import Any, List, Optional, Dict
 
@@ -17,6 +21,8 @@ from sentence_transformers import SentenceTransformer
 
 BASE_PATH = Path(__file__).resolve().parents[2]
 KNOWLEDGE_DIR = BASE_PATH / "var" / "knowledge"
+LOG_DIR = BASE_PATH / "var" / "log"
+LOG_FILE = LOG_DIR / "vector_service.log"
 
 CHUNK_INDEX_PATH = KNOWLEDGE_DIR / "vector.index"
 CHUNK_MAP_PATH = KNOWLEDGE_DIR / "vector.index.meta.json"
@@ -25,9 +31,47 @@ TAG_INDEX_PATH = KNOWLEDGE_DIR / "vector_tags.index"
 TAG_MAP_PATH = KNOWLEDGE_DIR / "vector_tags.index.meta.json"
 
 INDEX_META_PATH = KNOWLEDGE_DIR / "index_meta.json"
+INDEX_RUNTIME_PATH = KNOWLEDGE_DIR / "index_runtime.json"
 INDEX_NDJSON_PATH = KNOWLEDGE_DIR / "index.ndjson"
 
 
+# ============================================================
+# Logging
+# ============================================================
+
+logger = logging.getLogger("vector_service")
+logger.setLevel(logging.INFO)
+
+def setup_logging() -> None:
+    LOG_DIR.mkdir(parents=True, exist_ok=True)
+
+    fmt = logging.Formatter(
+        fmt="%(asctime)s %(levelname)s %(message)s",
+        datefmt="%Y-%m-%dT%H:%M:%S%z",
+    )
+
+    # Rotating file
+    file_handler = RotatingFileHandler(
+        str(LOG_FILE),
+        maxBytes=10 * 1024 * 1024,  # 10MB
+        backupCount=5,
+        encoding="utf-8",
+    )
+    file_handler.setFormatter(fmt)
+    file_handler.setLevel(logging.INFO)
+
+    # Console (stdout)
+    stream_handler = logging.StreamHandler()
+    stream_handler.setFormatter(fmt)
+    stream_handler.setLevel(logging.INFO)
+
+    # avoid duplicate handlers if uvicorn reloads workers
+    if not any(isinstance(h, RotatingFileHandler) for h in logger.handlers):
+        logger.addHandler(file_handler)
+    if not any(isinstance(h, logging.StreamHandler) for h in logger.handlers):
+        logger.addHandler(stream_handler)
+
+
 # ============================================================
 # FastAPI
 # ============================================================
@@ -44,6 +88,11 @@ tag_ids: Optional[List[Any]] = None
 
 loaded_embedding_model_name: Optional[str] = None
 
+current_index_version: Optional[int] = None
+current_runtime_stamp: Optional[str] = None
+
+reload_lock = threading.Lock()
+
 
 # ============================================================
 # Models
@@ -52,14 +101,24 @@ loaded_embedding_model_name: Optional[str] = None
 class SearchRequest(BaseModel):
     query: str
     limit: int = 8
-    doc_ids: Optional[List[str]] = None  # NEW
+    doc_ids: Optional[List[str]] = None
 
 
 # ============================================================
 # Loader
 # ============================================================
 
-def load_chunk_doc_map():
+def _safe_read_json(path: Path) -> Optional[dict]:
+    try:
+        if not path.exists():
+            return None
+        return json.loads(path.read_text(encoding="utf-8"))
+    except Exception as e:
+        logger.warning("Failed to read json %s: %s", str(path), str(e))
+        return None
+
+
+def load_chunk_doc_map() -> None:
     global chunk_doc_map
 
     chunk_doc_map = {}
@@ -67,61 +126,131 @@ def load_chunk_doc_map():
     if not INDEX_NDJSON_PATH.exists():
         return
 
-    with INDEX_NDJSON_PATH.open("r", encoding="utf-8") as f:
-        for line in f:
-            try:
-                row = json.loads(line)
-            except Exception:
+    try:
+        with INDEX_NDJSON_PATH.open("r", encoding="utf-8") as f:
+            for line in f:
+                try:
+                    row = json.loads(line)
+                except Exception:
+                    continue
+
+                chunk_id = row.get("chunk_id")
+                document_id = row.get("document_id")
+
+                if isinstance(chunk_id, str) and isinstance(document_id, str):
+                    chunk_doc_map[chunk_id] = document_id
+    except Exception as e:
+        logger.warning("Failed to load chunk-doc map from ndjson: %s", str(e))
+
+
+def load_all() -> None:
+    """
+    Reload everything deterministically (model + indices + maps),
+    guarded by reload_lock (thread-safe).
+    """
+    global model, chunk_index, chunk_ids
+    global tag_index, tag_ids
+    global loaded_embedding_model_name
+    global current_index_version
+    global current_runtime_stamp
+
+    with reload_lock:
+        meta = _safe_read_json(INDEX_META_PATH)
+        if not isinstance(meta, dict):
+            raise RuntimeError("index_meta.json not found or invalid")
+
+        embedding_model_name = meta.get("embedding_model")
+        index_version = meta.get("index_version")
+
+        if not embedding_model_name:
+            raise RuntimeError("embedding_model missing in index_meta.json")
+
+        # Reload model if needed
+        if model is None or embedding_model_name != loaded_embedding_model_name:
+            logger.info("[Reload] Loading embedding model: %s", embedding_model_name)
+            model = SentenceTransformer(embedding_model_name)
+            loaded_embedding_model_name = embedding_model_name
+
+        # Reload chunk index
+        if CHUNK_INDEX_PATH.exists() and CHUNK_MAP_PATH.exists():
+            logger.info("[Reload] Loading chunk index")
+            chunk_index = faiss.read_index(str(CHUNK_INDEX_PATH))
+            chunk_ids = _safe_read_json(CHUNK_MAP_PATH) or None
+            if not isinstance(chunk_ids, list):
+                chunk_index = None
+                chunk_ids = None
+                logger.warning("[Reload] chunk_ids meta invalid -> chunk index disabled")
+        else:
+            chunk_index = None
+            chunk_ids = None
+
+        # Load chunk → document map
+        logger.info("[Reload] Loading chunk-doc map")
+        load_chunk_doc_map()
+
+        # Reload tag index
+        if TAG_INDEX_PATH.exists() and TAG_MAP_PATH.exists():
+            logger.info("[Reload] Loading tag index")
+            tag_index = faiss.read_index(str(TAG_INDEX_PATH))
+            tag_ids = _safe_read_json(TAG_MAP_PATH) or None
+            if not isinstance(tag_ids, list):
+                tag_index = None
+                tag_ids = None
+                logger.warning("[Reload] tag_ids meta invalid -> tag index disabled")
+        else:
+            tag_index = None
+            tag_ids = None
+
+        # Runtime stamp (commit marker for tags+chunks)
+        runtime = _safe_read_json(INDEX_RUNTIME_PATH)
+        if isinstance(runtime, dict):
+            v = runtime.get("last_rebuild_at")
+            current_runtime_stamp = v if isinstance(v, str) else None
+        else:
+            current_runtime_stamp = None
+
+        current_index_version = index_version if isinstance(index_version, int) else None
+
+        logger.info("[Reload] Completed (index_version=%s runtime=%s)", str(current_index_version), str(current_runtime_stamp))
+
+
+# ============================================================
+# Observer (Enterprise Auto Reload)
+# ============================================================
+
+def observer_loop() -> None:
+    global current_index_version
+    global current_runtime_stamp
+
+    while True:
+        time.sleep(2)
+
+        try:
+            meta = _safe_read_json(INDEX_META_PATH)
+            if not isinstance(meta, dict):
                 continue
 
-            chunk_id = row.get("chunk_id")
-            document_id = row.get("document_id")
+            new_version = meta.get("index_version") if isinstance(meta.get("index_version"), int) else None
 
-            if isinstance(chunk_id, str) and isinstance(document_id, str):
-                chunk_doc_map[chunk_id] = document_id
+            runtime = _safe_read_json(INDEX_RUNTIME_PATH)
+            new_runtime = None
+            if isinstance(runtime, dict):
+                v = runtime.get("last_rebuild_at")
+                new_runtime = v if isinstance(v, str) else None
 
+            # Structure change (embedding, dim, scoring_version, etc.) -> reload
+            if new_version != current_index_version:
+                logger.info("[Observer] index_version changed (%s -> %s) -> Reload", str(current_index_version), str(new_version))
+                load_all()
+                continue
 
-def load_all():
-    global model, chunk_index, chunk_ids, tag_index, tag_ids, loaded_embedding_model_name
+            # Content change (chunks OR tags) -> reload
+            if new_runtime != current_runtime_stamp:
+                logger.info("[Observer] runtime changed (%s -> %s) -> Reload", str(current_runtime_stamp), str(new_runtime))
+                load_all()
 
-    if not INDEX_META_PATH.exists():
-        raise RuntimeError("index_meta.json not found")
-
-    meta = json.loads(INDEX_META_PATH.read_text())
-    embedding_model_name = meta.get("embedding_model")
-
-    if not embedding_model_name:
-        raise RuntimeError("embedding_model missing in index_meta.json")
-
-    # Reload model only if changed
-    if model is None or embedding_model_name != loaded_embedding_model_name:
-        print(f"[Reload] Loading embedding model: {embedding_model_name}")
-        model = SentenceTransformer(embedding_model_name)
-        loaded_embedding_model_name = embedding_model_name
-
-    # Reload chunk index
-    if CHUNK_INDEX_PATH.exists() and CHUNK_MAP_PATH.exists():
-        print("[Reload] Loading chunk index")
-        chunk_index = faiss.read_index(str(CHUNK_INDEX_PATH))
-        chunk_ids = json.loads(CHUNK_MAP_PATH.read_text())
-    else:
-        chunk_index = None
-        chunk_ids = None
-
-    # Load chunk → document map
-    print("[Reload] Loading chunk-doc map")
-    load_chunk_doc_map()
-
-    # Reload tag index
-    if TAG_INDEX_PATH.exists() and TAG_MAP_PATH.exists():
-        print("[Reload] Loading tag index")
-        tag_index = faiss.read_index(str(TAG_INDEX_PATH))
-        tag_ids = json.loads(TAG_MAP_PATH.read_text())
-    else:
-        tag_index = None
-        tag_ids = None
-
-    print("[Reload] Completed")
+        except Exception as e:
+            logger.error("[Observer ERROR] %s", str(e))
 
 
 # ============================================================
@@ -130,8 +259,15 @@ def load_all():
 
 @app.on_event("startup")
 def startup_event():
+    setup_logging()
+    logger.info("[VectorService] Startup")
+
     load_all()
-    print("[VectorService] Ready")
+
+    t = threading.Thread(target=observer_loop, daemon=True)
+    t.start()
+
+    logger.info("[VectorService] Ready (log=%s)", str(LOG_FILE))
 
 
 # ============================================================
@@ -145,11 +281,18 @@ def health():
         "chunk_index_loaded": chunk_index is not None,
         "tag_index_loaded": tag_index is not None,
         "model_loaded": model is not None,
+        "index_version": current_index_version,
+        "runtime_stamp": current_runtime_stamp,
+        "log_file": str(LOG_FILE),
     }
 
 
 @app.post("/reload")
 def reload():
+    """
+    Manual reload endpoint (kept for compatibility with mto:agent:vector:control --reload).
+    Auto-reload still runs via observer_loop.
+    """
     try:
         load_all()
         return {"status": "reloaded"}
@@ -159,13 +302,12 @@ def reload():
 
 @app.post("/search-chunks")
 def search_chunks(req: SearchRequest):
-    if chunk_index is None or chunk_ids is None:
+    if chunk_index is None or chunk_ids is None or model is None:
         raise HTTPException(status_code=503, detail="Chunk index not available")
 
     query_vec = model.encode([req.query], normalize_embeddings=True)
     query_vec = np.array(query_vec).astype("float32")
 
-    # Wenn doc_ids gesetzt sind → mehr holen, dann filtern
     effective_limit = req.limit
     if req.doc_ids:
         effective_limit = max(req.limit * 5, 50)
@@ -182,7 +324,6 @@ def search_chunks(req: SearchRequest):
 
         chunk_id = chunk_ids[idx]
 
-        # NEW: doc-scoped filter
         if req.doc_ids:
             doc_id = chunk_doc_map.get(chunk_id)
             if doc_id not in req.doc_ids:
@@ -201,7 +342,7 @@ def search_chunks(req: SearchRequest):
 
 @app.post("/search-tags")
 def search_tags(req: SearchRequest):
-    if tag_index is None or tag_ids is None:
+    if tag_index is None or tag_ids is None or model is None:
         raise HTTPException(status_code=503, detail="Tag index not available")
 
     query_vec = model.encode([req.query], normalize_embeddings=True)
@@ -210,6 +351,7 @@ def search_tags(req: SearchRequest):
     scores, indices = tag_index.search(query_vec, req.limit)
 
     results = []
+
     for score, idx in zip(scores[0], indices[0]):
         if idx == -1:
             continue
diff --git a/src/Command/TagsRebuildCommand.php b/src/Command/TagsRebuildCommand.php
index beeb5a0..15fb8fb 100644
--- a/src/Command/TagsRebuildCommand.php
+++ b/src/Command/TagsRebuildCommand.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace App\Command;
 
+use App\Index\IndexMetaManager;
 use App\Tag\TagNdjsonExporter;
 use App\Tag\TagVectorIndexBuilder;
 use Symfony\Component\Console\Attribute\AsCommand;
@@ -20,6 +21,7 @@ final class TagsRebuildCommand extends Command
     public function __construct(
         private readonly TagNdjsonExporter $exporter,
         private readonly TagVectorIndexBuilder $builder,
+        private readonly IndexMetaManager $metaManager,
     ) {
         parent::__construct();
     }
@@ -27,15 +29,32 @@ final class TagsRebuildCommand extends Command
     protected function execute(InputInterface $input, OutputInterface $output): int
     {
         try {
+            // -----------------------------------------
+            // 1) Export tags.ndjson
+            // -----------------------------------------
             $export = $this->exporter->export();
-            $output->writeln('<info>1/2 Exported tags.ndjson</info>');
+
+            $output->writeln('<info>1/3 Exported tags.ndjson</info>');
             $output->writeln('Path:  ' . $export['path']);
             $output->writeln('Tags:  ' . $export['tags']);
             $output->writeln('Lines: ' . $export['lines']);
             $output->writeln('Bytes: ' . $export['bytes']);
 
+            // -----------------------------------------
+            // 2) Build FAISS tag index
+            // -----------------------------------------
             $this->builder->build();
-            $output->writeln('<info>2/2 Built vector_tags.index</info>');
+
+            $output->writeln('<info>2/3 Built vector_tags.index</info>');
+
+            // -----------------------------------------
+            // 3) Enterprise Commit Marker
+            // -----------------------------------------
+            $this->metaManager->touchRuntime([
+                'last_tags_rebuild_at' => (new \DateTimeImmutable())->format(DATE_ATOM),
+            ]);
+
+            $output->writeln('<info>3/3 Runtime commit marker updated</info>');
         } catch (\Throwable $e) {
             $output->writeln('<error>ERROR: ' . $e->getMessage() . '</error>');
             return Command::FAILURE;
diff --git a/src/Index/IndexMetaManager.php b/src/Index/IndexMetaManager.php
index 34ec93d..9fedaae 100644
--- a/src/Index/IndexMetaManager.php
+++ b/src/Index/IndexMetaManager.php
@@ -106,6 +106,9 @@ final class IndexMetaManager
         $this->atomicWriteJson($this->runtimePath, $payload);
     }
 
+    /**
+     * Für Chunk-Rebuilds (harte Zahl + Commit-Timestamp).
+     */
     public function updateRuntimeStats(int $chunkCount): void
     {
         $this->ensureRuntimeFileExists();
@@ -118,7 +121,40 @@ final class IndexMetaManager
         $this->atomicWriteJson($this->runtimePath, $payload);
     }
 
-    public function getRuntimeChunkCount(): int
+    /**
+     * Enterprise-Commit-Marker für alles, was einen Reload im Vector-Service erfordern soll,
+     * ohne dass zwingend chunk_count aktualisiert werden kann (z.B. Tag-Rebuild).
+     *
+     * Beispiel:
+     *   touchRuntime(['last_tags_rebuild_at' => DATE_ATOM])
+     */
+    public function touchRuntime(array $extra = []): void
+    {
+        $this->ensureRuntimeFileExists();
+
+        $current = $this->readRuntime() ?? [];
+
+        // Grundschema absichern
+        if (!isset($current['chunk_count'])) {
+            $current['chunk_count'] = 0;
+        }
+
+        $payload = array_merge(
+            $current,
+            $extra,
+            [
+                // Commit-Marker IMMER setzen/überschreiben
+                'last_rebuild_at' => (new \DateTimeImmutable())->format(DATE_ATOM),
+            ]
+        );
+
+        $this->atomicWriteJson($this->runtimePath, $payload);
+    }
+
+    /**
+     * Runtime-Info lesen (z.B. für Tests, Debug, Polling).
+     */
+    public function readRuntime(): ?array
     {
         $this->ensureRuntimeFileExists();
 
@@ -127,9 +163,25 @@ final class IndexMetaManager
             true
         );
 
+        return is_array($data) ? $data : null;
+    }
+
+    public function getRuntimeChunkCount(): int
+    {
+        $data = $this->readRuntime();
+
         return (int)($data['chunk_count'] ?? 0);
     }
 
+    public function getRuntimeLastRebuildAt(): ?string
+    {
+        $data = $this->readRuntime();
+
+        $v = $data['last_rebuild_at'] ?? null;
+
+        return is_string($v) && $v !== '' ? $v : null;
+    }
+
     // =====================================================
     // INTERNAL ATOMIC JSON WRITE
     // =====================================================
diff --git a/src/Tag/TagVectorIndexBuilder.php b/src/Tag/TagVectorIndexBuilder.php
index 03f794f..8ef38d4 100644
--- a/src/Tag/TagVectorIndexBuilder.php
+++ b/src/Tag/TagVectorIndexBuilder.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace App\Tag;
 
+use App\Index\IndexMetaManager;
 use Psr\Log\LoggerInterface;
 
 final class TagVectorIndexBuilder
@@ -16,6 +17,7 @@ final class TagVectorIndexBuilder
         private readonly string $embeddingModel,
         private readonly int $timeoutSeconds,
         private readonly LoggerInterface $agentLogger,
+        private readonly IndexMetaManager $metaManager, // ✅ NEU
     ) {}
 
     public function build(): void
@@ -34,18 +36,14 @@ final class TagVectorIndexBuilder
         $finalIndex = $this->vectorTagsIndexPath;
         $finalMeta  = $finalIndex . '.meta.json';
 
-        // Ensure output dir exists
         $dir = \dirname($finalIndex);
         if (!\is_dir($dir)) {
             @\mkdir($dir, 0775, true);
         }
 
-        // Clean tmp leftovers
         @\unlink($tmpIndex);
         @\unlink($tmpMeta);
 
-        // Positional args:
-        // python vector_ingest_tags.py <tags.ndjson> <out.tmp> <model>
         $cmd = sprintf(
             '%s %s %s %s %s 2>&1',
             escapeshellarg($this->pythonBin),
@@ -73,20 +71,22 @@ final class TagVectorIndexBuilder
             throw new \RuntimeException('Tag vector ingest failed (exit=' . $exit . ')');
         }
 
-        // If no tags -> python may remove outputs and exit 0
         if (!is_file($tmpIndex) || !is_file($tmpMeta)) {
-            // treat as "no index" rather than hard error
             @\unlink($tmpIndex);
             @\unlink($tmpMeta);
             $this->agentLogger->warning('[tags] no tag index produced (maybe 0 tags).');
             return;
         }
 
-        // Atomic switch
         $this->atomicReplace($tmpIndex, $finalIndex);
         $this->atomicReplace($tmpMeta, $finalMeta);
 
-        $this->agentLogger->info('[tags] tag vector index build completed', [
+        // ✅ ENTERPRISE COMMIT MARKER
+        $this->metaManager->touchRuntime([
+            'last_tags_rebuild_at' => (new \DateTimeImmutable())->format(DATE_ATOM),
+        ]);
+
+        $this->agentLogger->info('[tags] tag vector index build completed + runtime committed', [
             'index' => $finalIndex,
             'meta'  => $finalMeta,
         ]);