68c800d2a3
### Summary: This enables users to **use** MCP inside the SDK. 1. You add a list of MCP servers to `Agent`, via `mcp_server=[...]` 2. When an agent runs, we look up its MCP tools and add them to the list of tools. 3. When a tool call occurs, we call the relevant MCP server. Notes: 1. There's some refactoring to make sure we send the full list of tools to the Runner/Model etc. 2. Right now, you could have a locally defined tool that conflicts with an MCP defined tool. I didn't add errors for that, will do in a followup. ### Test Plan: See unit tests. Also has an end to end example next PR.
109 lines
3.1 KiB
Python
109 lines
3.1 KiB
Python
import logging
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from typing import Any
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import pytest
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from mcp.types import Tool as MCPTool
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from pydantic import BaseModel
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from agents import FunctionTool, RunContextWrapper
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from agents.exceptions import AgentsException, ModelBehaviorError
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from agents.mcp import MCPServer, MCPUtil
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from .helpers import FakeMCPServer
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class Foo(BaseModel):
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bar: str
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baz: int
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class Bar(BaseModel):
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qux: str
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@pytest.mark.asyncio
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async def test_get_all_function_tools():
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"""Test that the get_all_function_tools function returns all function tools from a list of MCP
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servers.
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"""
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names = ["test_tool_1", "test_tool_2", "test_tool_3", "test_tool_4", "test_tool_5"]
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schemas = [
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{},
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{},
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{},
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Foo.model_json_schema(),
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Bar.model_json_schema(),
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]
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server1 = FakeMCPServer()
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server1.add_tool(names[0], schemas[0])
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server1.add_tool(names[1], schemas[1])
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server2 = FakeMCPServer()
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server2.add_tool(names[2], schemas[2])
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server2.add_tool(names[3], schemas[3])
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server3 = FakeMCPServer()
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server3.add_tool(names[4], schemas[4])
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servers: list[MCPServer] = [server1, server2, server3]
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tools = await MCPUtil.get_all_function_tools(servers)
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assert len(tools) == 5
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assert all(tool.name in names for tool in tools)
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for idx, tool in enumerate(tools):
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assert isinstance(tool, FunctionTool)
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assert tool.params_json_schema == schemas[idx]
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assert tool.name == names[idx]
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@pytest.mark.asyncio
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async def test_invoke_mcp_tool():
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"""Test that the invoke_mcp_tool function invokes an MCP tool and returns the result."""
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server = FakeMCPServer()
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server.add_tool("test_tool_1", {})
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ctx = RunContextWrapper(context=None)
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tool = MCPTool(name="test_tool_1", inputSchema={})
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await MCPUtil.invoke_mcp_tool(server, tool, ctx, "")
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# Just making sure it doesn't crash
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@pytest.mark.asyncio
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async def test_mcp_invoke_bad_json_errors(caplog: pytest.LogCaptureFixture):
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caplog.set_level(logging.DEBUG)
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"""Test that bad JSON input errors are logged and re-raised."""
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server = FakeMCPServer()
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server.add_tool("test_tool_1", {})
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ctx = RunContextWrapper(context=None)
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tool = MCPTool(name="test_tool_1", inputSchema={})
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with pytest.raises(ModelBehaviorError):
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await MCPUtil.invoke_mcp_tool(server, tool, ctx, "not_json")
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assert "Invalid JSON input for tool test_tool_1" in caplog.text
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class CrashingFakeMCPServer(FakeMCPServer):
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async def call_tool(self, tool_name: str, arguments: dict[str, Any] | None):
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raise Exception("Crash!")
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@pytest.mark.asyncio
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async def test_mcp_invocation_crash_causes_error(caplog: pytest.LogCaptureFixture):
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caplog.set_level(logging.DEBUG)
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"""Test that bad JSON input errors are logged and re-raised."""
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server = CrashingFakeMCPServer()
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server.add_tool("test_tool_1", {})
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ctx = RunContextWrapper(context=None)
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tool = MCPTool(name="test_tool_1", inputSchema={})
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with pytest.raises(AgentsException):
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await MCPUtil.invoke_mcp_tool(server, tool, ctx, "")
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assert "Error invoking MCP tool test_tool_1" in caplog.text
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