Feat/fast mcp settings (#361)

* Support settings dict for FastMCP server

* Fix settings spread

* Just use kwargs instead of settings arg

Author: rholinshead

examples/mcp_agent_server/asyncio/README.md

@@ -12,7 +12,7 @@ https://github.com/user-attachments/assets/f651af86-222d-4df0-8241-616414df66e4
 
 - Creating workflows with the `Workflow` base class
 - Registering workflows with an `MCPApp`
-- Exposing workflows as MCP tools using `create_mcp_server_for_app`
+- Exposing workflows as MCP tools using `create_mcp_server_for_app`, optionally using custom FastMCP settings
 - Connecting to an MCP server using `gen_client`
 - Running workflows remotely and monitoring their status
 
@@ -93,11 +93,18 @@ You can also run the server and client separately:
 
    ```bash
    uv run basic_agent_server.py
+
+   # Optionally, run with the example custom FastMCP settings
+   uv run basic_agent_server.py --custom-fastmcp-settings
    ```
 
 2. In another terminal, run the client:
+
    ```bash
    uv run client.py
+
+   # Optionally, run with the example custom FastMCP settings
+   uv run client.py --custom-fastmcp-settings
    ```
 
 ## MCP Clients

examples/mcp_agent_server/asyncio/basic_agent_server.py

@@ -7,6 +7,7 @@
 3. Declarative agent configuration using FastMCPApp decorators
 """
 
+import argparse
 import asyncio
 import os
 import logging
@@ -169,6 +170,15 @@ async def run(self, input: str) -> WorkflowResult[str]:
 
 
 async def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--custom-fastmcp-settings",
+        action="store_true",
+        help="Enable custom FastMCP settings for the server",
+    )
+    args = parser.parse_args()
+    use_custom_fastmcp_settings = args.custom_fastmcp_settings
+
     async with app.run() as agent_app:
         # Add the current directory to the filesystem server's args if needed
         context = agent_app.context
@@ -182,8 +192,15 @@ async def main():
         for workflow_id in agent_app.workflows:
             logger.info(f"  - {workflow_id}")
 
-        # Create the MCP server that exposes both workflows and agent configurations
-        mcp_server = create_mcp_server_for_app(agent_app)
+        # Create the MCP server that exposes both workflows and agent configurations,
+        # optionally using custom FastMCP settings
+        fast_mcp_settings = (
+            {"host": "localhost", "port": 8001, "debug": True, "log_level": "DEBUG"}
+            if use_custom_fastmcp_settings
+            else None
+        )
+        mcp_server = create_mcp_server_for_app(agent_app, **(fast_mcp_settings or {}))
+        logger.info(f"MCP Server settings: {mcp_server.settings}")
 
         # Add custom tool to get token usage for a workflow
         @mcp_server.tool(

examples/mcp_agent_server/asyncio/client.py

@@ -1,3 +1,4 @@
+import argparse
 import asyncio
 import json
 import time
@@ -11,6 +12,15 @@
 
 
 async def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--custom-fastmcp-settings",
+        action="store_true",
+        help="Enable custom FastMCP settings for the server",
+    )
+    args = parser.parse_args()
+    use_custom_fastmcp_settings = args.custom_fastmcp_settings
+
     # Create MCPApp to get the server registry
     app = MCPApp(name="workflow_mcp_client")
     async with app.run() as client_app:
@@ -21,11 +31,17 @@ async def main():
         logger.info("Connecting to workflow server...")
 
         # Override the server configuration to point to our local script
+        run_server_args = ["run", "basic_agent_server.py"]
+        if use_custom_fastmcp_settings:
+            logger.info("Using custom FastMCP settings for the server.")
+            run_server_args += ["--custom-fastmcp-settings"]
+        else:
+            logger.info("Using default FastMCP settings for the server.")
         context.server_registry.registry["basic_agent_server"] = MCPServerSettings(
             name="basic_agent_server",
             description="Local workflow server running the basic agent example",
             command="uv",
-            args=["run", "basic_agent_server.py"],
+            args=run_server_args,
         )
 
         # Connect to the workflow server

src/mcp_agent/server/app_server.py

@@ -81,12 +81,13 @@ def workflow_registry(self) -> WorkflowRegistry:
         return self.context.workflow_registry
 
 
-def create_mcp_server_for_app(app: MCPApp) -> FastMCP:
+def create_mcp_server_for_app(app: MCPApp, **kwargs: Any) -> FastMCP:
     """
     Create an MCP server for a given MCPApp instance.
 
     Args:
         app: The MCPApp instance to create a server for
+        kwargs: Optional FastMCP settings to configure the server.
 
     Returns:
         A configured FastMCP server instance
@@ -119,6 +120,7 @@ async def app_specific_lifespan(mcp: FastMCP) -> AsyncIterator[ServerContext]:
         # or use the MCPApp's description if available.
         instructions=f"MCP server exposing {app.name} workflows and agents. Description: {app.description}",
         lifespan=app_specific_lifespan,
+        **kwargs,
     )
 
     # region Workflow Tools