Adding Git MCP server example (openai#343)

- Adding new example showing a single agent interacting with local MCP
server for git

Author: rm-openai

examples/mcp/filesystem_example/README.md

@@ -1,6 +1,6 @@
 # MCP Filesystem Example
 
-This example uses the [fileystem MCP server](https://github.com/modelcontextprotocol/servers/tree/main/src/filesystem), running locally via `npx`.
+This example uses the [filesystem MCP server](https://github.com/modelcontextprotocol/servers/tree/main/src/filesystem), running locally via `npx`.
 
 Run it via:
 

examples/mcp/git_example/README.md

@@ -0,0 +1,25 @@
+# MCP Git Example
+
+This example uses the [git MCP server](https://github.com/modelcontextprotocol/servers/tree/main/src/git), running locally via `uvx`.
+
+Run it via:
+
+```
+uv run python examples/mcp/git_example/main.py
+```
+
+## Details
+
+The example uses the `MCPServerStdio` class from `agents`, with the command:
+
+```bash
+uvx mcp-server-git
+```
+Prior to running the agent, the user is prompted to provide a local directory path to their git repo. Using that, the Agent can invoke Git MCP tools like `git_log` to inspect the git commit log.
+
+Under the hood:
+
+1. The server is spun up in a subprocess, and exposes a bunch of tools like `git_log()`
+2. We add the server instance to the Agent via `mcp_agents`.
+3. Each time the agent runs, we call out to the MCP server to fetch the list of tools via `server.list_tools()`. The result is cached. 
+4. If the LLM chooses to use an MCP tool, we call the MCP server to run the tool via `server.run_tool()`.

examples/mcp/git_example/main.py

@@ -0,0 +1,48 @@
+import asyncio
+import shutil
+
+from agents import Agent, Runner, trace
+from agents.mcp import MCPServer, MCPServerStdio
+
+
+async def run(mcp_server: MCPServer, directory_path: str):
+    agent = Agent(
+        name="Assistant",
+        instructions=f"Answer questions about the git repository at {directory_path}, use that for repo_path",
+        mcp_servers=[mcp_server],
+    )
+
+    message = "Who's the most frequent contributor?"
+    print("\n" + "-" * 40)
+    print(f"Running: {message}")
+    result = await Runner.run(starting_agent=agent, input=message)
+    print(result.final_output)
+
+    message = "Summarize the last change in the repository."
+    print("\n" + "-" * 40)
+    print(f"Running: {message}")
+    result = await Runner.run(starting_agent=agent, input=message)
+    print(result.final_output)
+
+
+async def main():
+    # Ask the user for the directory path
+    directory_path = input("Please enter the path to the git repository: ")
+
+    async with MCPServerStdio(
+        params={
+            "command": "uvx",
+            "args": [
+                "mcp-server-git"
+            ]
+        }
+    ) as server:
+        with trace(workflow_name="MCP Git Example"):
+            await run(server, directory_path)
+
+
+if __name__ == "__main__":
+    if not shutil.which("uvx"):
+        raise RuntimeError("uvx is not installed. Please install it with `pip install uvx`.")
+
+    asyncio.run(main())