feat(py): add mcp sample test

py/samples/mcp/README.md

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+# MCP Sample
+
+This sample demonstrates using the MCP (Model Context Protocol) plugin with Genkit Python SDK.
+
+## Setup environment
+
+Obtain an API key from [ai.dev](https://ai.dev).
+
+Export the API key as env variable `GEMINI\_API\_KEY` in your shell
+configuration.
+
+### Run the MCP Client/Host
+```bash
+cd py/samples/mcp
+genkit start -- uv run src/main.py
+```
+
+This will:
+1. Connect to the configured MCP servers
+2. Execute sample flows demonstrating tool usage
+3. Clean up connections on exit
+
+### Run the HTTP MCP Server
+```bash
+cd py/samples/mcp
+genkit start -- uv run src/http_server.py
+```
+
+This will:
+1. Start an MCP server over HTTP/SSE on port 3334.
+2. Expose a test tool named test_http.
+
+### Run the MCP Server
+```bash
+cd py/samples/mcp
+genkit start -- uv run src/server.py
+```
+
+This starts an MCP server on stdio that other MCP clients can connect to.
+
+## Requirements
+
+- Python 3.10+
+- `mcp` - Model Context Protocol Python SDK
+- `genkit` - Genkit Python SDK
+- `genkit-plugins-google-genai` - Google AI plugin for Genkit
+
+## MCP Servers Used
+
+The sample connects to these MCP servers (must be available):
+- **mcp-server-git** - Install via `uvx mcp-server-git`
+- **@modelcontextprotocol/server-filesystem** - Install via npm
+- **@modelcontextprotocol/server-everything** - Install via npm
+
+## Learn More
+
+- [MCP Documentation](https://modelcontextprotocol.io/)
+- [Genkit Python Documentation](https://firebase.google.com/docs/genkit)
+- [MCP Plugin Source](../../plugins/mcp/)

py/samples/mcp/pyproject.toml

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+# Copyright 2026 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.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+[project]
+dependencies = [
+  "genkit",
+  "genkit-plugin-google-genai",
+  "genkit-plugins-mcp",
+  "mcp",
+]
+description = "MCP sample application for Genkit Python SDK"
+name = "mcp-sample"
+readme = "README.md"
+requires-python = ">=3.10"
+version = "0.1.0"
+
+[tool.uv.sources]
+genkit                     = { workspace = true }
+genkit-plugin-google-genai = { workspace = true }
+genkit-plugins-mcp         = { workspace = true }
+
+[build-system]
+build-backend = "hatchling.build"
+requires      = ["hatchling"]
+
+[tool.hatch.build.targets.wheel]
+packages = ["src"]

py/samples/mcp/run.sh

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+#!/usr/bin/env bash
+# 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.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+case "$1" in
+  server)
+    shift
+    exec genkit start -- uv run src/server.py "$@"
+    ;;
+  http)
+    shift
+    exec genkit start -- uv run src/http_server.py "$@"
+    ;;
+  *)
+    # Default to main.py
+    exec genkit start -- uv run src/main.py "$@"
+    ;;
+esac

py/samples/mcp/src/http_server.py

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+# 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.
+
+"""
+HTTP MCP Server Example
+
+This demonstrates creating an HTTP-based MCP server using SSE transport
+with Starlette and the official MCP Python SDK.
+"""
+
+import asyncio
+import logging
+
+import mcp.types as types
+import uvicorn
+from mcp.server import Server
+from mcp.server.sse import SseServerTransport
+from starlette.applications import Starlette
+from starlette.responses import Response
+from starlette.routing import Mount, Route
+
+# Configure logging
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+
+async def main():
+    """Start the HTTP MCP server."""
+
+    # Create SSE transport logic
+    # The endpoint '/mcp/' is where clients will POST messages
+    sse = SseServerTransport('/mcp/')
+
+    async def handle_sse(request):
+        """Handle incoming SSE connections."""
+        async with sse.connect_sse(request.scope, request.receive, request._send) as streams:
+            read_stream, write_stream = streams
+
+            # Create a new server instance for this session
+            # This mirrors the JS logic of creating a new McpServer per connection
+            server = Server('example-server', version='1.0.0')
+
+            @server.list_tools()
+            async def list_tools() -> list[types.Tool]:
+                return [
+                    types.Tool(
+                        name='test_http',
+                        description='Test HTTP transport',
+                        inputSchema={'type': 'object', 'properties': {}},
+                    )
+                ]
+
+            @server.call_tool()
+            async def call_tool(name: str, arguments: dict) -> list[types.TextContent]:
+                if name == 'test_http':
+                    # In this SSE implementation, valid session ID is internal
+                    # but we can return a confirmation.
+                    return [types.TextContent(type='text', text='Session Active')]
+                raise ValueError(f'Unknown tool: {name}')
+
+            # Run the server with the streams
+            await server.run(read_stream, write_stream, server.create_initialization_options())
+
+        # Return empty response after connection closes
+        return Response()
+
+    # Define routes
+    # GET /mcp -> Starts SSE stream
+    # POST /mcp/ -> Handles messages (via SseServerTransport)
+    routes = [
+        Route('/mcp', endpoint=handle_sse, methods=['GET']),
+        Mount('/mcp/', app=sse.handle_post_message),
+    ]
+
+    app = Starlette(routes=routes)
+
+    config = uvicorn.Config(app, host='0.0.0.0', port=3334, log_level='info')
+    server = uvicorn.Server(config)
+
+    print('HTTP MCP server running on http://localhost:3334/mcp')
+    await server.serve()
+
+
+if __name__ == '__main__':
+    asyncio.run(main())