feat: add McpPlugin protocol and entry_points discovery#10
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Plugins register via entry_points group 'ros2_medkit_mcp.plugins'. Plugin tools merged into list_tools() and call_tool() dispatch. Startup/shutdown lifecycle in server_stdio and server_http. Broken plugins logged and skipped.
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Pull request overview
This pull request adds a plugin system to enable extensibility of the MCP server. It introduces a McpPlugin Protocol that defines the interface for external packages to register additional MCP tools via Python's entry_points mechanism. The system integrates plugin discovery, lifecycle management (startup/shutdown), and tool dispatch into the existing server architecture.
Changes:
- Adds
McpPluginProtocol withlist_tools(),call_tool(),startup(), andshutdown()methods for plugin implementations - Implements
discover_plugins()function usingentry_points(group="ros2_medkit_mcp.plugins")for automatic plugin registration - Integrates plugin lifecycle and tool dispatch into both stdio and HTTP transport servers with proper error handling
Reviewed changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated 6 comments.
Show a summary per file
| File | Description |
|---|---|
src/ros2_medkit_mcp/plugin.py |
New module defining McpPlugin Protocol and discover_plugins() function for entry_points-based plugin discovery |
src/ros2_medkit_mcp/mcp_app.py |
Updates register_tools() and call_tool() to merge plugin tools with core tools and dispatch to plugins as fallback |
src/ros2_medkit_mcp/server_stdio.py |
Adds plugin discovery and lifecycle management (startup/shutdown) to stdio server entrypoint |
src/ros2_medkit_mcp/server_http.py |
Adds plugin discovery and lifecycle management (startup/shutdown) to HTTP server entrypoint |
tests/test_plugin_discovery.py |
New test file covering plugin discovery scenarios including successful discovery, empty state, and broken plugins |
- Fix ruff lint errors (import order, unused import, type annotation) - Build tool→plugin map at registration time for O(1) dispatch - Make plugin dispatch authoritative (first declaring plugin owns it) - Track successfully started plugins; only shutdown those on exit
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Feb 21, 2026
…otocol validation - Add tool name collision detection against built-in tools (TOOL_ALIASES) and inter-plugin duplicates during plugin tool registration - Extract start_plugins()/shutdown_plugins() helpers to plugin.py, removing duplicated loops from server_stdio.py and server_http.py - Add hasattr check in discover_plugins() to skip non-conforming plugins - Pass only started_plugins to setup_mcp_app (not all discovered) - Move setup_mcp_app into on_startup in server_http.py so plugin tools are only registered after successful startup - Add tests for dispatch, collision detection, and lifecycle helpers
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Summary
McpPluginProtocol class defining the interface for MCP server plugins (list_tools,call_tool,startup,shutdown)discover_plugins()using Pythonentry_points(groupros2_medkit_mcp.plugins) for automatic plugin registrationmcp_app.py,server_stdio.py, andserver_http.pyCloses #9
Test plan
tests/test_plugin_discovery.py- 3 tests covering discovery, broken plugin handling, empty state