Files
agent-framework/python/samples/02-agents/mcp/agent_as_mcp_server.py
T
Eduard van Valkenburg 9c57680f00 Python: Add header_provider to Streamable HTTP MCP servers (#4849)
* Python: Add header_provider to MCPStreamableHTTPTool (#4808)

Add a header_provider callback parameter to MCPStreamableHTTPTool that
enables injecting dynamic per-request HTTP headers from runtime kwargs
(originating from FunctionInvocationContext.kwargs set in agent middleware).

The implementation uses contextvars and httpx event hooks to ensure headers
are task-local and safe for concurrent tool calls:

- header_provider receives the runtime kwargs dict and returns headers
- call_tool sets a ContextVar before delegating to MCPTool.call_tool
- An httpx request event hook reads from the ContextVar and injects headers

Example usage:
    mcp_tool = MCPStreamableHTTPTool(
        name="web-api",
        url="https://api.example.com/mcp",
        header_provider=lambda kwargs: {
            "X-Auth-Token": kwargs.get("auth_token", ""),
        },
    )

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review feedback for #4808: Python: [Bug]: Unable to pass AgentContext to MCPStreamableHTTPTool

* Add test for header_provider via FunctionTool.invoke with FunctionInvocationContext

Addresses PR review comment: exercises the full pipeline from
FunctionInvocationContext.kwargs through FunctionTool.invoke to
MCPStreamableHTTPTool.call_tool and header_provider, rather than
testing call_tool in isolation.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review feedback for #4808: review comment fixes

* Fix streamable MCP transport defaults

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix Azure AI test client mocks

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix MCP runtime kwarg regressions

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Stabilize MCP tool runtime kwargs

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Use context kwargs in MCP wrappers

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* updated mcp samples

* fix link

---------

Co-authored-by: Copilot <copilot@github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-03-31 17:23:49 +00:00

81 lines
2.3 KiB
Python

# Copyright (c) Microsoft. All rights reserved.
from typing import Annotated, Any
import anyio
from agent_framework import Agent, tool
from agent_framework.openai import OpenAIChatClient
from dotenv import load_dotenv
# Load environment variables from .env file
load_dotenv()
"""
This sample demonstrates how to expose an Agent as an MCP server.
To run this sample, set up your MCP host (like Claude Desktop or VSCode GitHub Copilot Agents)
with the following configuration:
```json
{
"servers": {
"agent-framework": {
"command": "uv",
"args": [
"--directory=<path to project>/agent-framework/python/samples/02-agents/mcp",
"run",
"agent_as_mcp_server.py"
],
"env": {
"OPENAI_API_KEY": "<OpenAI API key>",
"OPENAI_MODEL": "<OpenAI Responses model ID>",
}
}
}
}
```
"""
# NOTE: approval_mode="never_require" is for sample brevity. Use "always_require" in production; see samples/02-agents/tools/function_tool_with_approval.py and samples/02-agents/tools/function_tool_with_approval_and_sessions.py.
@tool(approval_mode="never_require")
def get_specials() -> Annotated[str, "Returns the specials from the menu."]:
return """
Special Soup: Clam Chowder
Special Salad: Cobb Salad
Special Drink: Chai Tea
"""
@tool(approval_mode="never_require")
def get_item_price(
menu_item: Annotated[str, "The name of the menu item."],
) -> Annotated[str, "Returns the price of the menu item."]:
return "$9.99"
async def run() -> None:
# Define an agent
# Agent's name and description provide better context for AI model
agent = Agent(
client=OpenAIChatClient(),
name="RestaurantAgent",
description="Answer questions about the menu.",
tools=[get_specials, get_item_price],
)
# Expose the agent as an MCP server
server = agent.as_mcp_server()
# Run server
from mcp.server.stdio import stdio_server
async def handle_stdin(stdin: Any | None = None, stdout: Any | None = None) -> None:
async with stdio_server() as (read_stream, write_stream):
await server.run(read_stream, write_stream, server.create_initialization_options())
await handle_stdin()
if __name__ == "__main__":
anyio.run(run)