fix: Drive Starlette lifespan ourselves for SSE transport too

README.md

@@ -183,6 +183,35 @@ claude mcp add semcode --transport stdio --env MCP_TRANSPORT=stdio -- uv run --d
 `GITHUB_TOKEN`, `QDRANT_URL`, and embedding provider variables are still read from `.env` in the
 project directory — `uv run` picks it up automatically.
 
+### Connecting over SSE
+
+> SSE is the legacy MCP HTTP transport, superseded by
+> `streamable-http`. Only use it for clients that don't yet support `streamable-http` — new setups
+> should use the [`streamable-http` setup above](#connecting-ai-clients).
+
+Set `MCP_TRANSPORT=sse` in `.env` (or the environment) and start the server the same way as
+`streamable-http` (`make docker-up` / `make docker-up-jina`, or `uv run python -m server.main`
+locally). The server exposes an SSE endpoint at `http://localhost:8090/sse`.
+
+**Claude Code (CLI)**
+
+```bash
+claude mcp add --transport sse semcode http://localhost:8090/sse
+```
+
+**Other MCP clients** — add an entry to the client's MCP config:
+
+```json
+{
+  "mcpServers": {
+    "semcode": {
+      "transport": "sse",
+      "url": "http://localhost:8090/sse"
+    }
+  }
+}
+```
+
 ## Indexing
 
 The indexing pipeline is symbol-oriented: each function, class, method, or component becomes its own

server/main.py

@@ -60,8 +60,10 @@ async def lifespan(_: FastMCP) -> AsyncIterator[None]:
     logger.info("semcode MCP server stopped.")
 
 
-# For streamable-http we drive the Starlette app's lifespan ourselves (see main),
+# For streamable-http and sse we drive the Starlette app's lifespan ourselves (see main),
 # so the per-MCP-session lifespan would re-init the store on every client connect.
+_HTTP_TRANSPORTS = {"streamable-http", "sse"}
+
 mcp = FastMCP(
     "semcode",
     instructions=(
@@ -71,7 +73,7 @@ async def lifespan(_: FastMCP) -> AsyncIterator[None]:
         "PHP, Kotlin, Scala, Swift, Dart, Bash, SQL, Lua, R, Dockerfile, Docker "
         "Compose, Markdown, JSON, HTML, CSS, and XML."
     ),
-    lifespan=lifespan if settings.mcp_transport != "streamable-http" else None,
+    lifespan=lifespan if settings.mcp_transport not in _HTTP_TRANSPORTS else None,
     host=settings.mcp_host,
     port=settings.mcp_port,
 )
@@ -106,8 +108,12 @@ def main() -> None:
     register_system_prompts(mcp)
     register_http_routes(mcp)
 
-    if settings.mcp_transport == "streamable-http":
-        app = mcp.streamable_http_app()
+    if settings.mcp_transport in _HTTP_TRANSPORTS:
+        app = (
+            mcp.streamable_http_app()
+            if settings.mcp_transport == "streamable-http"
+            else mcp.sse_app()
+        )
         _wrap_http_lifespan(app)
         uvicorn.run(
             app,