mirror of
https://github.com/encounter/adk-python.git
synced 2026-07-09 18:19:28 -07:00
Wei Sun (Jack)andCopybara-Service
fa5c546a55
Merge https://github.com/google/adk-python/pull/3411
## Summary
Fixes AgentTool cleanup to prevent MCP session errors by calling `runner.close()` after sub-agent execution.
## Problem
When using AgentTool with MCP tools, the runner cleanup happened during garbage collection in a different async task context, causing:
```
RuntimeError: Attempted to exit cancel scope in a different task than it was entered in
```
## Solution
- Call `await runner.close()` immediately after sub-agent execution in AgentTool
- This ensures MCP sessions and other resources are cleaned up in the correct async task context
- Updated test mock to include the close() method
## Demo Agents
Added two comprehensive demo agents showing how to use AgentTool with MCP tools:
### mcp_in_agent_tool_remote (SSE mode)
- Uses HTTP/SSE connection to remote MCP server
- Zero-installation setup with `uvx`
- Demonstrates server-side MCP deployment pattern
### mcp_in_agent_tool_stdio (stdio mode)
- Uses subprocess connection with automatic server launch
- Fully automatic setup with `uvx` subdirectory syntax
- Demonstrates embedded MCP deployment pattern
Both demos:
- Use Gemini 2.5 Flash
- Include example prompts for JSON Schema exploration
- Have comprehensive READMEs with architecture diagrams
- Follow ADK agent structure conventions
## Testing
- ✅ All existing unit tests pass
- ✅ Manual testing with both SSE and stdio modes
- ✅ Verified cleanup happens in correct async context
- ✅ No more cancel scope errors with MCP tools
## Related
- Fixes #1112
- Related to #929
Co-authored-by: Wei Sun (Jack) <weisun@google.com>
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/3411 from google:fix/agent-tool-mcp-cleanup 9ae753b5a4
PiperOrigin-RevId: 828651896
78 lines
2.7 KiB
Python
78 lines
2.7 KiB
Python
# Copyright 2025 Google LLC
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
from google.adk.agents import Agent
|
|
from google.adk.tools import AgentTool
|
|
from google.adk.tools.mcp_tool import McpToolset
|
|
from google.adk.tools.mcp_tool.mcp_session_manager import StdioConnectionParams
|
|
from mcp import StdioServerParameters
|
|
|
|
# Create MCP toolset
|
|
# This uses the simple-tool MCP server via stdio
|
|
# The server will be launched automatically using uvx from the subdirectory
|
|
mcp_toolset = McpToolset(
|
|
connection_params=StdioConnectionParams(
|
|
server_params=StdioServerParameters(
|
|
command="uvx",
|
|
args=[
|
|
"--from",
|
|
"git+https://github.com/modelcontextprotocol/python-sdk.git#subdirectory=examples/servers/simple-tool",
|
|
"mcp-simple-tool",
|
|
],
|
|
),
|
|
timeout=10.0,
|
|
)
|
|
)
|
|
|
|
# Create sub-agent with MCP tools
|
|
# This agent has direct access to MCP tools
|
|
sub_agent = Agent(
|
|
name="mcp_helper",
|
|
model="gemini-2.5-flash",
|
|
description=(
|
|
"A helpful assistant with access to MCP tools for fetching websites."
|
|
),
|
|
instruction="""You are a helpful assistant with access to MCP tools.
|
|
|
|
When the user asks for help:
|
|
1. Explain what tools you have available (website fetching)
|
|
2. Use the appropriate tool if needed
|
|
3. Provide clear and helpful responses
|
|
|
|
You have access to a website fetcher tool via MCP. Use it to fetch and return website content.""",
|
|
tools=[mcp_toolset],
|
|
)
|
|
|
|
# Wrap sub-agent as an AgentTool
|
|
# This allows the main agent to delegate tasks to the sub-agent
|
|
# The sub-agent has access to MCP tools for fetching websites
|
|
mcp_agent_tool = AgentTool(agent=sub_agent)
|
|
|
|
# Create main agent
|
|
# This agent can delegate to the sub-agent via AgentTool
|
|
root_agent = Agent(
|
|
name="main_agent",
|
|
model="gemini-2.5-flash",
|
|
description="Main agent that can delegate to a sub-agent with MCP tools.",
|
|
instruction="""You are a helpful assistant. You have access to a sub-agent (mcp_helper)
|
|
that has MCP tools for fetching websites.
|
|
|
|
When the user asks for help:
|
|
- If they need to fetch a website, call the mcp_helper tool
|
|
- Otherwise, respond directly
|
|
|
|
Always be helpful and explain what you're doing.""",
|
|
tools=[mcp_agent_tool],
|
|
)
|