From c9648389c41fecfd6d1962f00db6c934fa111093 Mon Sep 17 00:00:00 2001
From: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
Date: Sat, 17 May 2025 11:38:40 -0400
Subject: [PATCH 1/2] Store server instance as fastmcp_server

---
 docs/deployment/asgi.mdx       |  3 +++
 src/fastmcp/server/http.py     | 12 ++++++++++--
 tests/server/test_app_state.py | 27 +++++++++++++++++++++++++++
 3 files changed, 40 insertions(+), 2 deletions(-)
 create mode 100644 tests/server/test_app_state.py

diff --git a/docs/deployment/asgi.mdx b/docs/deployment/asgi.mdx
index 6fc5624fb..ace7ee136 100644
--- a/docs/deployment/asgi.mdx
+++ b/docs/deployment/asgi.mdx
@@ -45,6 +45,9 @@ sse_app = mcp.http_app(transport="sse")
 
 Both approaches return a Starlette application that can be integrated with other ASGI-compatible web frameworks.
 
+The returned app stores the `FastMCP` instance on `app.state.fastmcp_server`, so you
+can access it from custom middleware or routes via `request.app.state.fastmcp_server`.
+
 The MCP server's endpoint is mounted at the root path `/mcp` for Streamable HTTP transport, and `/sse` for SSE transport, though you can change these paths by passing a `path` argument to the `http_app()` method:
 
 ```python
diff --git a/src/fastmcp/server/http.py b/src/fastmcp/server/http.py
index 2437e85f8..d718d610a 100644
--- a/src/fastmcp/server/http.py
+++ b/src/fastmcp/server/http.py
@@ -247,11 +247,15 @@ def create_sse_app(
         server_middleware.extend(middleware)
 
     # Create and return the app
-    return create_base_app(
+    app = create_base_app(
         routes=server_routes,
         middleware=server_middleware,
         debug=debug,
     )
+    # Store the FastMCP server instance on the Starlette app state
+    app.state.fastmcp_server = server
+
+    return app
 
 
 def create_streamable_http_app(
@@ -344,9 +348,13 @@ def create_streamable_http_app(
             yield
 
     # Create and return the app with lifespan
-    return create_base_app(
+    app = create_base_app(
         routes=server_routes,
         middleware=server_middleware,
         debug=debug,
         lifespan=lifespan,
     )
+    # Store the FastMCP server instance on the Starlette app state
+    app.state.fastmcp_server = server
+
+    return app
diff --git a/tests/server/test_app_state.py b/tests/server/test_app_state.py
new file mode 100644
index 000000000..dddb625c9
--- /dev/null
+++ b/tests/server/test_app_state.py
@@ -0,0 +1,27 @@
+import pytest
+from fastmcp.server import FastMCP
+from fastmcp.server.http import create_sse_app, create_streamable_http_app
+
+
+def test_http_app_sets_mcp_server_state():
+    server = FastMCP(name="StateTest")
+    app = server.http_app()
+    assert app.state.fastmcp_server is server
+
+
+def test_http_app_sse_sets_mcp_server_state():
+    server = FastMCP(name="StateTest")
+    app = server.http_app(transport="sse")
+    assert app.state.fastmcp_server is server
+
+
+def test_create_streamable_http_app_sets_state():
+    server = FastMCP(name="StateTest")
+    app = create_streamable_http_app(server, "/mcp")
+    assert app.state.fastmcp_server is server
+
+
+def test_create_sse_app_sets_state():
+    server = FastMCP(name="StateTest")
+    app = create_sse_app(server, message_path="/message", sse_path="/sse")
+    assert app.state.fastmcp_server is server

From e76a076da5ee1fb73f48843dd8911c72c7f28b28 Mon Sep 17 00:00:00 2001
From: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
Date: Sat, 17 May 2025 11:47:00 -0400
Subject: [PATCH 2/2] Fix static checks

---
 tests/server/test_app_state.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/server/test_app_state.py b/tests/server/test_app_state.py
index dddb625c9..609089400 100644
--- a/tests/server/test_app_state.py
+++ b/tests/server/test_app_state.py
@@ -1,4 +1,3 @@
-import pytest
 from fastmcp.server import FastMCP
 from fastmcp.server.http import create_sse_app, create_streamable_http_app