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docs: clarify streamable_http_path configuration when mounting servers (#1172)
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‎README.md‎

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],
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lifespan=lifespan,
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)
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# Note: Clients connect to http://localhost:8000/echo/mcp and http://localhost:8000/math/mcp
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# To mount at the root of each path (e.g., /echo instead of /echo/mcp):
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# echo_mcp.settings.streamable_http_path = "/"
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# math_mcp.settings.streamable_http_path = "/"
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```
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_Full example: [examples/snippets/servers/streamable_starlette_mount.py](https://github.com/modelcontextprotocol/python-sdk/blob/main/examples/snippets/servers/streamable_starlette_mount.py)_
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For more information on mounting applications in Starlette, see the [Starlette documentation](https://www.starlette.io/routing/#submounting-routes).
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#### StreamableHTTP servers
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You can mount the StreamableHTTP server to an existing ASGI server using the `streamable_http_app` method. This allows you to integrate the StreamableHTTP server with other ASGI applications.
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##### Basic mounting
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<!-- snippet-source examples/snippets/servers/streamable_http_basic_mounting.py -->
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```python
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"""
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Basic example showing how to mount StreamableHTTP server in Starlette.
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Run from the repository root:
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uvicorn examples.snippets.servers.streamable_http_basic_mounting:app --reload
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"""
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from starlette.applications import Starlette
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from starlette.routing import Mount
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from mcp.server.fastmcp import FastMCP
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# Create MCP server
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mcp = FastMCP("My App")
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@mcp.tool()
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def hello() -> str:
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"""A simple hello tool"""
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return "Hello from MCP!"
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# Mount the StreamableHTTP server to the existing ASGI server
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app = Starlette(
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routes=[
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Mount("/", app=mcp.streamable_http_app()),
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]
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)
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```
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_Full example: [examples/snippets/servers/streamable_http_basic_mounting.py](https://github.com/modelcontextprotocol/python-sdk/blob/main/examples/snippets/servers/streamable_http_basic_mounting.py)_
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<!-- /snippet-source -->
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##### Host-based routing
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<!-- snippet-source examples/snippets/servers/streamable_http_host_mounting.py -->
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```python
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"""
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Example showing how to mount StreamableHTTP server using Host-based routing.
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Run from the repository root:
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uvicorn examples.snippets.servers.streamable_http_host_mounting:app --reload
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"""
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from starlette.applications import Starlette
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from starlette.routing import Host
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from mcp.server.fastmcp import FastMCP
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# Create MCP server
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mcp = FastMCP("MCP Host App")
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@mcp.tool()
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def domain_info() -> str:
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"""Get domain-specific information"""
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return "This is served from mcp.acme.corp"
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# Mount using Host-based routing
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app = Starlette(
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routes=[
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Host("mcp.acme.corp", app=mcp.streamable_http_app()),
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]
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)
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```
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_Full example: [examples/snippets/servers/streamable_http_host_mounting.py](https://github.com/modelcontextprotocol/python-sdk/blob/main/examples/snippets/servers/streamable_http_host_mounting.py)_
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<!-- /snippet-source -->
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##### Multiple servers with path configuration
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<!-- snippet-source examples/snippets/servers/streamable_http_multiple_servers.py -->
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```python
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"""
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Example showing how to mount multiple StreamableHTTP servers with path configuration.
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Run from the repository root:
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uvicorn examples.snippets.servers.streamable_http_multiple_servers:app --reload
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"""
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from starlette.applications import Starlette
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from starlette.routing import Mount
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from mcp.server.fastmcp import FastMCP
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# Create multiple MCP servers
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api_mcp = FastMCP("API Server")
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chat_mcp = FastMCP("Chat Server")
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@api_mcp.tool()
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def api_status() -> str:
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"""Get API status"""
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return "API is running"
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@chat_mcp.tool()
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def send_message(message: str) -> str:
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"""Send a chat message"""
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return f"Message sent: {message}"
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# Configure servers to mount at the root of each path
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# This means endpoints will be at /api and /chat instead of /api/mcp and /chat/mcp
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api_mcp.settings.streamable_http_path = "/"
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chat_mcp.settings.streamable_http_path = "/"
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# Mount the servers
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app = Starlette(
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routes=[
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Mount("/api", app=api_mcp.streamable_http_app()),
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Mount("/chat", app=chat_mcp.streamable_http_app()),
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]
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)
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```
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_Full example: [examples/snippets/servers/streamable_http_multiple_servers.py](https://github.com/modelcontextprotocol/python-sdk/blob/main/examples/snippets/servers/streamable_http_multiple_servers.py)_
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<!-- /snippet-source -->
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##### Path configuration at initialization
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<!-- snippet-source examples/snippets/servers/streamable_http_path_config.py -->
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```python
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"""
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Example showing path configuration during FastMCP initialization.
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Run from the repository root:
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uvicorn examples.snippets.servers.streamable_http_path_config:app --reload
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"""
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from starlette.applications import Starlette
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from starlette.routing import Mount
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from mcp.server.fastmcp import FastMCP
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# Configure streamable_http_path during initialization
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# This server will mount at the root of wherever it's mounted
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mcp_at_root = FastMCP("My Server", streamable_http_path="/")
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@mcp_at_root.tool()
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def process_data(data: str) -> str:
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"""Process some data"""
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return f"Processed: {data}"
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# Mount at /process - endpoints will be at /process instead of /process/mcp
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app = Starlette(
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routes=[
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Mount("/process", app=mcp_at_root.streamable_http_app()),
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]
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)
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```
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_Full example: [examples/snippets/servers/streamable_http_path_config.py](https://github.com/modelcontextprotocol/python-sdk/blob/main/examples/snippets/servers/streamable_http_path_config.py)_
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<!-- /snippet-source -->
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#### SSE servers
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> **Note**: SSE transport is being superseded by [Streamable HTTP transport](https://modelcontextprotocol.io/specification/2025-03-26/basic/transports#streamable-http).

‎examples/snippets/servers/streamable_http_basic_mounting.py‎

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"""
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Basic example showing how to mount StreamableHTTP server in Starlette.
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Run from the repository root:
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uvicorn examples.snippets.servers.streamable_http_basic_mounting:app --reload
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"""
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from starlette.applications import Starlette
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from starlette.routing import Mount
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from mcp.server.fastmcp import FastMCP
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# Create MCP server
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mcp = FastMCP("My App")
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@mcp.tool()
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def hello() -> str:
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"""A simple hello tool"""
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return "Hello from MCP!"
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# Mount the StreamableHTTP server to the existing ASGI server
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app = Starlette(
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routes=[
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Mount("/", app=mcp.streamable_http_app()),
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]
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)

‎examples/snippets/servers/streamable_http_host_mounting.py‎

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"""
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Example showing how to mount StreamableHTTP server using Host-based routing.
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Run from the repository root:
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uvicorn examples.snippets.servers.streamable_http_host_mounting:app --reload
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"""
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from starlette.applications import Starlette
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from starlette.routing import Host
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from mcp.server.fastmcp import FastMCP
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# Create MCP server
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mcp = FastMCP("MCP Host App")
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@mcp.tool()
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def domain_info() -> str:
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"""Get domain-specific information"""
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return "This is served from mcp.acme.corp"
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# Mount using Host-based routing
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app = Starlette(
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routes=[
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Host("mcp.acme.corp", app=mcp.streamable_http_app()),
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]
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)

‎examples/snippets/servers/streamable_http_multiple_servers.py‎

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"""
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Example showing how to mount multiple StreamableHTTP servers with path configuration.
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Run from the repository root:
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uvicorn examples.snippets.servers.streamable_http_multiple_servers:app --reload
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"""
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from starlette.applications import Starlette
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from starlette.routing import Mount
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from mcp.server.fastmcp import FastMCP
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# Create multiple MCP servers
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api_mcp = FastMCP("API Server")
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chat_mcp = FastMCP("Chat Server")
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@api_mcp.tool()
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def api_status() -> str:
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"""Get API status"""
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return "API is running"
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@chat_mcp.tool()
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def send_message(message: str) -> str:
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"""Send a chat message"""
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return f"Message sent: {message}"
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# Configure servers to mount at the root of each path
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# This means endpoints will be at /api and /chat instead of /api/mcp and /chat/mcp
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api_mcp.settings.streamable_http_path = "/"
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chat_mcp.settings.streamable_http_path = "/"
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# Mount the servers
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app = Starlette(
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routes=[
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Mount("/api", app=api_mcp.streamable_http_app()),
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Mount("/chat", app=chat_mcp.streamable_http_app()),
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]
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)

‎examples/snippets/servers/streamable_http_path_config.py‎

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"""
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Example showing path configuration during FastMCP initialization.
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Run from the repository root:
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uvicorn examples.snippets.servers.streamable_http_path_config:app --reload
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"""
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from starlette.applications import Starlette
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from starlette.routing import Mount
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from mcp.server.fastmcp import FastMCP
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# Configure streamable_http_path during initialization
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# This server will mount at the root of wherever it's mounted
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mcp_at_root = FastMCP("My Server", streamable_http_path="/")
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@mcp_at_root.tool()
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def process_data(data: str) -> str:
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"""Process some data"""
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return f"Processed: {data}"
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# Mount at /process - endpoints will be at /process instead of /process/mcp
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app = Starlette(
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routes=[
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Mount("/process", app=mcp_at_root.streamable_http_app()),
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]
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)

‎examples/snippets/servers/streamable_starlette_mount.py‎

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],
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lifespan=lifespan,
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)
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# Note: Clients connect to http://localhost:8000/echo/mcp and http://localhost:8000/math/mcp
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# To mount at the root of each path (e.g., /echo instead of /echo/mcp):
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# echo_mcp.settings.streamable_http_path = "/"
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# math_mcp.settings.streamable_http_path = "/"

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