diff --git a/app/main.py b/app/main.py
index c88d992..a2b04ca 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1,5 +1,6 @@
 import logging
 import uuid
+from contextlib import asynccontextmanager
 
 from fastapi import FastAPI, HTTPException, BackgroundTasks
 from fastapi.middleware.cors import CORSMiddleware
@@ -7,7 +8,7 @@ from fastapi.responses import StreamingResponse
 
 from app.auth import ServiceAuthDependency
 from app.config import settings, MAX_MESSAGE_LENGTH
-from app.embeddings import RetrieverDependency, IndexerDependency, get_retriever, reset_retriever
+from app.embeddings import RetrieverDependency, IndexerDependency, get_retriever, reset_retriever, get_indexer
 from app.embeddings.retriever import RetrievedChunk
 from app.intent import IntentClassifierDependency
 from app.llm import AdapterDependency, LLMError, llm_exception_to_http
@@ -31,11 +32,35 @@ logging.basicConfig(
 )
 logger = logging.getLogger(__name__)
 
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """Startup and shutdown lifecycle management."""
+    # Startup: auto-index if FAISS index is missing
+    retriever = get_retriever()
+    if not retriever.is_loaded:
+        logger.info("FAISS index not found, building index on startup...")
+        try:
+            indexer = get_indexer()
+            result = await indexer.build_index()
+            reset_retriever()  # Reset to load newly built index
+            logger.info(f"Startup indexing completed: {result.chunks_indexed} chunks from {result.artifacts_processed} artifacts")
+        except Exception as e:
+            logger.error(f"Startup indexing failed: {e}")
+    else:
+        logger.info(f"FAISS index loaded: {retriever.index_size} vectors")
+
+    yield  # App runs here
+
+    # Shutdown: nothing to clean up
+
+
 # Create FastAPI app
 app = FastAPI(
     title="Tyndale AI Service",
     description="LLM Chat Service for algorithmic trading support",
     version="0.1.0",
+    lifespan=lifespan,
 )
 
 # Add CORS middleware