En la primera parte creamos nuestro primer servidor MCP con FastMCP y aprendimos a exponer funciones como tools, filtrarlas por tags y componer servidores. En este capítulo configuramos la **capa de transporte**, controlamos qué argumentos se exponen, accedemos al **contexto** de la petición y creamos nuestro primer **resource**.
⚠️ Este capítulo continúa el código de la parte anterior. Para ejecutarlo necesitas el entorno y el servidor de la Parte 1.
📚 **Esta entrada es parte de la serie _MCP con FastMCP_**, dividida en cuatro capítulos que se leen en orden:
> * Parte 1: Primer servidor y tools
* 👉 **Parte 2: Transporte, contexto y resources**
* Parte 3: Resources avanzados y prompts
* Parte 4: HTTP, autenticación y cliente
Capa de transporte
Si al servidor MCP no le indicamos la capa de transporte, por defecto se usa stdio. Pero podemos indicárselo mediante el parámetro transport cuando lo ejecutamos
mcp.run(
transport="stdio"
)Sin embargo, si el cliente y el servidor no están en el mismo ordenador, podemos usar http como capa de transporte
Servidor MCP
En el servidor, solo tenemos que indicar que queremos usar http como capa de transporte, el host y el puerto.
mcp.run(
transport="streamable-http",
host="0.0.0.0",
port=8000,
)InputPython%%writefile gitHub_MCP_server/github_server.pyimport httpxfrom typing import Optionalfrom fastmcp import FastMCPfrom github import GITHUB_TOKEN, create_github_headers# Create FastMCP servermcp = FastMCP(name="GitHubMCP",instructions="This server provides tools, resources and prompts to interact with the GitHub API.",include_tags={"public"},exclude_tags={"first_issue"})sub_mcp = FastMCP(name="SubMCP",)@mcp.tool(tags={"public", "production"})async def list_repository_issues(owner: str, repo_name: str) -> list[dict]:"""Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list of dictionaries, each containing information about an issue"""# Limit to first 10 issues to avoid very long responsesapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=open&per_page=10"print(f"Fetching issues from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No open issues found for this repository.")return [{"message": "No open issues found for this repository."}]issues_summary = []for issue in issues_data:# Create a more concise summarysummary = f"#{issue.get('number', 'N/A')}: {issue.get('title', 'No title')}"if issue.get('comments', 0) > 0:summary += f" ({issue.get('comments')} comments)"issues_summary.append({"number": issue.get("number"),"title": issue.get("title"),"user": issue.get("user", {}).get("login"),"url": issue.get("html_url"),"comments": issue.get("comments"),"summary": summary})print(f"Found {len(issues_summary)} open issues.")# Add context informationresult = {"total_found": len(issues_summary),"repository": f"{owner}/{repo_name}","note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues","issues": issues_summary}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.tool(tags={"private", "development"})async def list_more_repository_issues(owner: str, repo_name: str) -> list[dict]:"""Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list of dictionaries, each containing information about an issue"""# Limit to first 100 issues to avoid very long responsesapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=open&per_page=100"print(f"Fetching issues from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No open issues found for this repository.")return [{"message": "No open issues found for this repository."}]issues_summary = []for issue in issues_data:# Create a more concise summarysummary = f"#{issue.get('number', 'N/A')}: {issue.get('title', 'No title')}"if issue.get('comments', 0) > 0:summary += f" ({issue.get('comments')} comments)"issues_summary.append({"number": issue.get("number"),"title": issue.get("title"),"user": issue.get("user", {}).get("login"),"url": issue.get("html_url"),"comments": issue.get("comments"),"summary": summary})print(f"Found {len(issues_summary)} open issues.")# Add context informationresult = {"total_found": len(issues_summary),"repository": f"{owner}/{repo_name}","note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues","issues": issues_summary}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.tool(tags={"public", "first_issue"})async def first_repository_issue(owner: str, repo_name: str) -> list[dict]:"""Gets the first issue ever created in a GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list containing information about the first issue created"""# Get the first issue by sorting by creation date in ascending orderapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=all&sort=created&direction=asc&per_page=1"print(f"Fetching first issue from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No issues found for this repository.")return [{"message": "No issues found for this repository."}]first_issue = issues_data[0]# Create a detailed summary of the first issuesummary = f"#{first_issue.get('number', 'N/A')}: {first_issue.get('title', 'No title')}"if first_issue.get('comments', 0) > 0:summary += f" ({first_issue.get('comments')} comments)"issue_info = {"number": first_issue.get("number"),"title": first_issue.get("title"),"user": first_issue.get("user", {}).get("login"),"url": first_issue.get("html_url"),"state": first_issue.get("state"),"comments": first_issue.get("comments"),"created_at": first_issue.get("created_at"),"updated_at": first_issue.get("updated_at"),"body": first_issue.get("body", "")[:500] + "..." if len(first_issue.get("body", "")) > 500 else first_issue.get("body", ""),"summary": summary}print(f"Found first issue: #{first_issue.get('number')} created on {first_issue.get('created_at')}")# Add context informationresult = {"repository": f"{owner}/{repo_name}","note": "This is the very first issue created in this repository","first_issue": issue_info}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@sub_mcp.tool(tags={"public"})def hello_world() -> str:"""Returns a simple greeting."""return "Hello, world!"mcp.mount("sub_mcp", sub_mcp)if __name__ == "__main__":print("DEBUG: Starting FastMCP GitHub server...")print(f"DEBUG: Server name: {mcp.name}")# Initialize and run the server, run with uv run client.py http://localhost:8000/mcpmcp.run(transport="streamable-http",host="0.0.0.0",port=8000,)Copied
Overwriting gitHub_MCP_server/github_server.py
Cliente MCP
En el cliente, lo que hay que cambiar es que antes realizábamos la conexión, pasando el path del servidor (async def connect_to_server(self, server_script_path: str)), mientras que ahora lo hacemos pasándole la URL del servidor (async def connect_to_server(self, server_url: str)).
InputPython%%writefile client_MCP/client.pyimport sysimport asynciofrom contextlib import AsyncExitStackfrom anthropic import Anthropicfrom dotenv import load_dotenvfrom fastmcp import Client# Load environment variables from .env fileload_dotenv()class FastMCPClient:"""FastMCP client that integrates with Claude to process user queriesand use tools exposed by a FastMCP server."""def __init__(self):"""Initialize the FastMCP client with Anthropic and resource management."""self.exit_stack = AsyncExitStack()self.anthropic = Anthropic()self.client = Noneasync def connect_to_server(self, server_url: str):"""Connect to the specified FastMCP server via HTTP.Args:server_url: URL of the HTTP server (e.g., "http://localhost:8000")"""print(f"🔗 Connecting to FastMCP HTTP server: {server_url}")# Create FastMCP client for HTTP connection using SSE transportself.client = Client(server_url)# Note: FastMCP Client automatically detects HTTP URLs and uses SSE transportprint("✅ Client created successfully")async def list_available_tools(self):"""List available tools in the FastMCP server."""try:# Get list of tools from the server using FastMCP contextasync with self.client as client:tools = await client.list_tools()if tools:print(f" 🛠️ Available tools ({len(tools)}):")print("=" * 50)for tool in tools:print(f"📋 {tool.name}")if tool.description:print(f" Description: {tool.description}")# Show parameters if availableif hasattr(tool, 'inputSchema') and tool.inputSchema:if 'properties' in tool.inputSchema:params = list(tool.inputSchema['properties'].keys())print(f" Parameters: {', '.join(params)}")print()else:print("⚠️ No tools found in the server")except Exception as e:print(f"❌ Error listing tools: {str(e)}")async def process_query(self, query: str) -> str:"""Process a user query, interacting with Claude and FastMCP tools.Args:query: User queryReturns:str: Final processed response"""try:# Use FastMCP context for all operationsasync with self.client as client:# Get available toolstools_list = await client.list_tools()# Prepare tools for Claude in correct formatclaude_tools = []for tool in tools_list:claude_tool = {"name": tool.name,"description": tool.description or f"Tool {tool.name}","input_schema": tool.inputSchema or {"type": "object", "properties": {}}}claude_tools.append(claude_tool)# Create initial message for Claudemessages = [{"role": "user","content": query}]# First call to Clauderesponse = self.anthropic.messages.create(model="claude-3-5-sonnet-20241022",max_tokens=6000,messages=messages,tools=claude_tools if claude_tools else None)# Process Claude's responseresponse_text = ""for content_block in response.content:if content_block.type == "text":response_text += content_block.textelif content_block.type == "tool_use":# Claude wants to use a tooltool_name = content_block.nametool_args = content_block.inputtool_call_id = content_block.idprint(f"🔧 Claude wants to use: {tool_name}")print(f"📝 Arguments: {tool_args}")try:# Execute tool on the FastMCP servertool_result = await client.call_tool(tool_name, tool_args)print(f"✅ Tool executed successfully")# Add tool result to the conversationmessages.append({"role": "assistant","content": response.content})# Format result for Claudeif tool_result:# Convert result to string format for Clauderesult_content = str(tool_result)messages.append({"role": "user","content": [{"type": "tool_result","tool_use_id": tool_call_id,"content": f"Tool result: {result_content}"}]})else:messages.append({"role": "user","content": [{"type": "tool_result","tool_use_id": tool_call_id,"content": "Tool executed without response content"}]})# Second call to Claude with the tool resultfinal_response = self.anthropic.messages.create(model="claude-3-5-sonnet-20241022",max_tokens=6000,messages=messages,tools=claude_tools if claude_tools else None)# Extract text from the final responsefor final_content in final_response.content:if final_content.type == "text":response_text += final_content.textexcept Exception as e:error_msg = f"❌ Error executing {tool_name}: {str(e)}"print(error_msg)response_text += f" {error_msg}"return response_textexcept Exception as e:error_msg = f"❌ Error processing query: {str(e)}"print(error_msg)return error_msgasync def chat_loop(self):"""Main chat loop with user interaction."""print(" 🤖 FastMCP HTTP client started. Write 'quit', 'q', 'exit', 'salir' to exit.")print("💬 You can ask questions about GitHub repositories!")print("📚 The client can use tools from the FastMCP HTTP server")print("🌐 Connected via Server-Sent Events (SSE)")print("-" * 60)while True:try:# Request user inputuser_input = input(" 👤 You: ").strip()if user_input.lower() in ['quit', 'q', 'exit', 'salir']:print("👋 Bye!")breakif not user_input:continueprint(" 🤔 Claude is thinking...")# Process queryresponse = await self.process_query(user_input)# Show responseprint(f" 🤖 Claude: {response}")except KeyboardInterrupt:print(" 👋 Disconnecting...")breakexcept Exception as e:print(f" ❌ Error in chat: {str(e)}")continueasync def cleanup(self):"""Clean up resources and close connections."""print("🧹 Cleaning up resources...")# FastMCP Client cleanup is handled automatically by context managerawait self.exit_stack.aclose()print("✅ Resources released")async def main():"""Main function that initializes and runs the FastMCP client."""# Verify command line argumentsif len(sys.argv) != 2:print("❌ Usage: python client.py <http_server_url>")print("📝 Example: python client.py http://localhost:8000")print("📝 Note: Now connects to HTTP server instead of executing script")sys.exit(1)server_url = sys.argv[1]# Validate URL formatif not server_url.startswith(('http://', 'https://')):print("❌ Error: Server URL must start with http:// or https://")print("📝 Example: python client.py http://localhost:8000")sys.exit(1)# Create and run clientclient = FastMCPClient()try:# Connect to the serverawait client.connect_to_server(server_url)# List available tools after connectionawait client.list_available_tools()# Start chat loopawait client.chat_loop()except Exception as e:print(f"❌ Fatal error: {str(e)}")finally:# Ensure resources are cleaned upawait client.cleanup()if __name__ == "__main__":# Entry point of the scriptasyncio.run(main())Copied
Overwriting client_MCP/client.py
Prueba del MCP por http
Para probar, primero tenemos que ejecutar el cliente para que se levante la URL y el puerto
InputPython!cd gitHub_MCP_server && source .venv/bin/activate && uv run github_server.pyCopied
/Users/macm1/Documents/web/portafolio/posts/gitHub_MCP_server/github_server.py:240: DeprecationWarning: Mount prefixes are now optional and the first positional argument should be the server you want to mount.mcp.mount("sub_mcp", sub_mcp)DEBUG: Starting FastMCP GitHub server...DEBUG: Server name: GitHubMCP[06/28/25 10:33:36] INFO Starting MCP server 'GitHubMCP' with ]8;id=281189;file:///Users/macm1/Documents/web/portafolio/posts/gitHub_MCP_server/.venv/lib/python3.11/site-packages/fastmcp/server/server.py\server.py]8;;\:]8;id=128713;file:///Users/macm1/Documents/web/portafolio/posts/gitHub_MCP_server/.venv/lib/python3.11/site-packages/fastmcp/server/server.py#1297\1297]8;;\transport 'streamable-http' onhttp://0.0.0.0:8000/mcp/INFO: Started server process [89401]INFO: Waiting for application startup.INFO: Application startup complete.INFO: Uvicorn running on http://0.0.0.0:8000 (Press CTRL+C to quit)
Ahora ejecutamos el cliente, dándole la URL del servidor MCP.
InputPython!cd client_MCP && source .venv/bin/activate && uv run client.py http://localhost:8000/mcpCopied
🔗 Connecting to FastMCP HTTP server: http://localhost:8000/mcp✅ Client created successfully🛠️ Available tools (2):==================================================📋 sub_mcp_hello_worldDescription: Returns a simple greeting.Parameters:📋 list_repository_issuesDescription: Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list of dictionaries, each containing information about an issueParameters: owner, repo_name🤖 FastMCP HTTP client started. Write 'quit', 'q', 'exit', 'salir' to exit.💬 You can ask questions about GitHub repositories!📚 The client can use tools from the FastMCP HTTP server🌐 Connected via Server-Sent Events (SSE)------------------------------------------------------------👤 You:
Vemos que se ha establecido la conexión sin problema.
Vuelta del servidor a STDIO
Volvemos a establecer STDIO como capa de transporte del servidor
InputPython%%writefile gitHub_MCP_server/github_server.pyimport httpxfrom typing import Optionalfrom fastmcp import FastMCPfrom github import GITHUB_TOKEN, create_github_headers# Create FastMCP servermcp = FastMCP(name="GitHubMCP",instructions="This server provides tools, resources and prompts to interact with the GitHub API.",include_tags={"public"},exclude_tags={"first_issue"})sub_mcp = FastMCP(name="SubMCP",)@mcp.tool(tags={"public", "production"})async def list_repository_issues(owner: str, repo_name: str) -> list[dict]:"""Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list of dictionaries, each containing information about an issue"""# Limit to first 10 issues to avoid very long responsesapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=open&per_page=10"print(f"Fetching issues from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No open issues found for this repository.")return [{"message": "No open issues found for this repository."}]issues_summary = []for issue in issues_data:# Create a more concise summarysummary = f"#{issue.get('number', 'N/A')}: {issue.get('title', 'No title')}"if issue.get('comments', 0) > 0:summary += f" ({issue.get('comments')} comments)"issues_summary.append({"number": issue.get("number"),"title": issue.get("title"),"user": issue.get("user", {}).get("login"),"url": issue.get("html_url"),"comments": issue.get("comments"),"summary": summary})print(f"Found {len(issues_summary)} open issues.")# Add context informationresult = {"total_found": len(issues_summary),"repository": f"{owner}/{repo_name}","note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues","issues": issues_summary}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.tool(tags={"private", "development"})async def list_more_repository_issues(owner: str, repo_name: str) -> list[dict]:"""Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list of dictionaries, each containing information about an issue"""# Limit to first 100 issues to avoid very long responsesapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=open&per_page=100"print(f"Fetching issues from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No open issues found for this repository.")return [{"message": "No open issues found for this repository."}]issues_summary = []for issue in issues_data:# Create a more concise summarysummary = f"#{issue.get('number', 'N/A')}: {issue.get('title', 'No title')}"if issue.get('comments', 0) > 0:summary += f" ({issue.get('comments')} comments)"issues_summary.append({"number": issue.get("number"),"title": issue.get("title"),"user": issue.get("user", {}).get("login"),"url": issue.get("html_url"),"comments": issue.get("comments"),"summary": summary})print(f"Found {len(issues_summary)} open issues.")# Add context informationresult = {"total_found": len(issues_summary),"repository": f"{owner}/{repo_name}","note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues","issues": issues_summary}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.tool(tags={"public", "first_issue"})async def first_repository_issue(owner: str, repo_name: str) -> list[dict]:"""Gets the first issue ever created in a GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list containing information about the first issue created"""# Get the first issue by sorting by creation date in ascending orderapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=all&sort=created&direction=asc&per_page=1"print(f"Fetching first issue from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No issues found for this repository.")return [{"message": "No issues found for this repository."}]first_issue = issues_data[0]# Create a detailed summary of the first issuesummary = f"#{first_issue.get('number', 'N/A')}: {first_issue.get('title', 'No title')}"if first_issue.get('comments', 0) > 0:summary += f" ({first_issue.get('comments')} comments)"issue_info = {"number": first_issue.get("number"),"title": first_issue.get("title"),"user": first_issue.get("user", {}).get("login"),"url": first_issue.get("html_url"),"state": first_issue.get("state"),"comments": first_issue.get("comments"),"created_at": first_issue.get("created_at"),"updated_at": first_issue.get("updated_at"),"body": first_issue.get("body", "")[:500] + "..." if len(first_issue.get("body", "")) > 500 else first_issue.get("body", ""),"summary": summary}print(f"Found first issue: #{first_issue.get('number')} created on {first_issue.get('created_at')}")# Add context informationresult = {"repository": f"{owner}/{repo_name}","note": "This is the very first issue created in this repository","first_issue": issue_info}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@sub_mcp.tool(tags={"public"})def hello_world() -> str:"""Returns a simple greeting."""return "Hello, world!"mcp.mount("sub_mcp", sub_mcp)if __name__ == "__main__":print("DEBUG: Starting FastMCP GitHub server...")print(f"DEBUG: Server name: {mcp.name}")# Initialize and run the servermcp.run(transport="stdio")Copied
Overwriting gitHub_MCP_server/github_server.py
Argumentos excluídos
Servidor MCP
Supongamos que queremos tener trazabilidad de la ID del usuario que ha hecho una petición, tendríamos que añadir un parámetro a la tool que se ejecute con dicha información. Pero esa información es irrelevante para el LLM, incluso por temas de seguridad, a lo mejor no queremos que dicha ID se pueda filtrar
Por lo que para que no se le pase un parámetro al LLM, a la hora de definir una tool podemos indicar que se excluya un parámetro mediante exclude_args.
InputPython%%writefile gitHub_MCP_server/github_server.pyimport httpxfrom fastmcp import FastMCPfrom github import GITHUB_TOKEN, create_github_headersUSER_ID = 1234567890# Create FastMCP servermcp = FastMCP(name="GitHubMCP",instructions="This server provides tools, resources and prompts to interact with the GitHub API.",include_tags={"public"},exclude_tags={"first_issue"})sub_mcp = FastMCP(name="SubMCP",)@mcp.tool(tags={"public", "production"},exclude_args=["user_id"], # user_id has to be injected by server, not provided by LLM)async def list_repository_issues(owner: str, repo_name: str, user_id: int = USER_ID) -> list[dict]:"""Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list of dictionaries, each containing information about an issue"""# Limit to first 10 issues to avoid very long responsesapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=open&per_page=10"print(f"Fetching issues from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No open issues found for this repository.")return [{"message": "No open issues found for this repository."}]issues_summary = []for issue in issues_data:# Create a more concise summarysummary = f"#{issue.get('number', 'N/A')}: {issue.get('title', 'No title')}"if issue.get('comments', 0) > 0:summary += f" ({issue.get('comments')} comments)"issues_summary.append({"number": issue.get("number"),"title": issue.get("title"),"user": issue.get("user", {}).get("login"),"url": issue.get("html_url"),"comments": issue.get("comments"),"summary": summary})print(f"Found {len(issues_summary)} open issues.")# Add context informationresult = {"total_found": len(issues_summary),"repository": f"{owner}/{repo_name}","note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues","issues": issues_summary,"requested_by_user_id": user_id}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.tool(tags={"private", "development"})async def list_more_repository_issues(owner: str, repo_name: str) -> list[dict]:"""Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list of dictionaries, each containing information about an issue"""# Limit to first 100 issues to avoid very long responsesapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=open&per_page=100"print(f"Fetching issues from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No open issues found for this repository.")return [{"message": "No open issues found for this repository."}]issues_summary = []for issue in issues_data:# Create a more concise summarysummary = f"#{issue.get('number', 'N/A')}: {issue.get('title', 'No title')}"if issue.get('comments', 0) > 0:summary += f" ({issue.get('comments')} comments)"issues_summary.append({"number": issue.get("number"),"title": issue.get("title"),"user": issue.get("user", {}).get("login"),"url": issue.get("html_url"),"comments": issue.get("comments"),"summary": summary})print(f"Found {len(issues_summary)} open issues.")# Add context informationresult = {"total_found": len(issues_summary),"repository": f"{owner}/{repo_name}","note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues","issues": issues_summary}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.tool(tags={"public", "first_issue"})async def first_repository_issue(owner: str, repo_name: str) -> list[dict]:"""Gets the first issue ever created in a GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list containing information about the first issue created"""# Get the first issue by sorting by creation date in ascending orderapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=all&sort=created&direction=asc&per_page=1"print(f"Fetching first issue from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No issues found for this repository.")return [{"message": "No issues found for this repository."}]first_issue = issues_data[0]# Create a detailed summary of the first issuesummary = f"#{first_issue.get('number', 'N/A')}: {first_issue.get('title', 'No title')}"if first_issue.get('comments', 0) > 0:summary += f" ({first_issue.get('comments')} comments)"issue_info = {"number": first_issue.get("number"),"title": first_issue.get("title"),"user": first_issue.get("user", {}).get("login"),"url": first_issue.get("html_url"),"state": first_issue.get("state"),"comments": first_issue.get("comments"),"created_at": first_issue.get("created_at"),"updated_at": first_issue.get("updated_at"),"body": first_issue.get("body", "")[:500] + "..." if len(first_issue.get("body", "")) > 500 else first_issue.get("body", ""),"summary": summary}print(f"Found first issue: #{first_issue.get('number')} created on {first_issue.get('created_at')}")# Add context informationresult = {"repository": f"{owner}/{repo_name}","note": "This is the very first issue created in this repository","first_issue": issue_info}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@sub_mcp.tool(tags={"public"})def hello_world() -> str:"""Returns a simple greeting."""return "Hello, world!"mcp.mount("sub_mcp", sub_mcp)if __name__ == "__main__":print("DEBUG: Starting FastMCP GitHub server...")print(f"DEBUG: Server name: {mcp.name}")# Initialize and run the servermcp.run(transport="stdio")Copied
Overwriting gitHub_MCP_server/github_server.py
Como se puede ver, en la tool list_repository_issues hemos indicado que se excluya el parámetro user_id.
@mcp.tool(
tags={"public", "production"},
exclude_args=["user_id"], # user_id has to be injected by server, not provided by LLM
)
async def list_repository_issues(owner: str, repo_name: str, user_id: int = USER_ID) -> list[dict]:Aunque luego devolvemos "requested_by_user_id": user_id
result = {
"total_found": len(issues_summary),
"repository": f"{owner}/{repo_name}",
"note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues",
"issues": issues_summary,
"requested_by_user_id": user_id
}Es decir, le estamos pasando la ID al LLM en el resultado. Pero en este caso, es para que a la hora de ejecutar la tool veamos que se ha ejecutado con dicha ID.
Contexto
Podemos pasar información de contexto del servidor al cliente y viceversa.
Servidor MCP
Vamos a añadir contexto a nuestro servidor MCP.
InputPython%%writefile gitHub_MCP_server/github_server.pyimport httpxfrom fastmcp import FastMCP, Contextfrom github import GITHUB_TOKEN, create_github_headersUSER_ID = 1234567890# Create FastMCP servermcp = FastMCP(name="GitHubMCP",instructions="This server provides tools, resources and prompts to interact with the GitHub API.",include_tags={"public"},exclude_tags={"first_issue"})sub_mcp = FastMCP(name="SubMCP",)@mcp.tool(tags={"public", "production"},exclude_args=["user_id"], # user_id has to be injected by server, not provided by LLM)async def list_repository_issues(owner: str, repo_name: str, ctx: Context, user_id: int = USER_ID) -> list[dict]:"""Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')ctx: The context of the requestuser_id: The user ID (automatically injected by the server)Returns:list[dict]: A list of dictionaries, each containing information about an issue"""# Limit to first 10 issues to avoid very long responsesapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=open&per_page=10"ctx.info(f"Fetching issues from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:ctx.info("No open issues found for this repository.")return [{"message": "No open issues found for this repository."}]issues_summary = []for issue in issues_data:# Create a more concise summarysummary = f"#{issue.get('number', 'N/A')}: {issue.get('title', 'No title')}"if issue.get('comments', 0) > 0:summary += f" ({issue.get('comments')} comments)"issues_summary.append({"number": issue.get("number"),"title": issue.get("title"),"user": issue.get("user", {}).get("login"),"url": issue.get("html_url"),"comments": issue.get("comments"),"summary": summary})ctx.info(f"Found {len(issues_summary)} open issues.")# Add context informationresult = {"total_found": len(issues_summary),"repository": f"{owner}/{repo_name}","note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues","issues": issues_summary,"requested_by_user_id": user_id}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"ctx.error(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:ctx.error(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.tool(tags={"private", "development"})async def list_more_repository_issues(owner: str, repo_name: str) -> list[dict]:"""Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list of dictionaries, each containing information about an issue"""# Limit to first 100 issues to avoid very long responsesapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=open&per_page=100"print(f"Fetching issues from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No open issues found for this repository.")return [{"message": "No open issues found for this repository."}]issues_summary = []for issue in issues_data:# Create a more concise summarysummary = f"#{issue.get('number', 'N/A')}: {issue.get('title', 'No title')}"if issue.get('comments', 0) > 0:summary += f" ({issue.get('comments')} comments)"issues_summary.append({"number": issue.get("number"),"title": issue.get("title"),"user": issue.get("user", {}).get("login"),"url": issue.get("html_url"),"comments": issue.get("comments"),"summary": summary})print(f"Found {len(issues_summary)} open issues.")# Add context informationresult = {"total_found": len(issues_summary),"repository": f"{owner}/{repo_name}","note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues","issues": issues_summary}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.tool(tags={"public", "first_issue"})async def first_repository_issue(owner: str, repo_name: str) -> list[dict]:"""Gets the first issue ever created in a GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list containing information about the first issue created"""# Get the first issue by sorting by creation date in ascending orderapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=all&sort=created&direction=asc&per_page=1"print(f"Fetching first issue from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No issues found for this repository.")return [{"message": "No issues found for this repository."}]first_issue = issues_data[0]# Create a detailed summary of the first issuesummary = f"#{first_issue.get('number', 'N/A')}: {first_issue.get('title', 'No title')}"if first_issue.get('comments', 0) > 0:summary += f" ({first_issue.get('comments')} comments)"issue_info = {"number": first_issue.get("number"),"title": first_issue.get("title"),"user": first_issue.get("user", {}).get("login"),"url": first_issue.get("html_url"),"state": first_issue.get("state"),"comments": first_issue.get("comments"),"created_at": first_issue.get("created_at"),"updated_at": first_issue.get("updated_at"),"body": first_issue.get("body", "")[:500] + "..." if len(first_issue.get("body", "")) > 500 else first_issue.get("body", ""),"summary": summary}print(f"Found first issue: #{first_issue.get('number')} created on {first_issue.get('created_at')}")# Add context informationresult = {"repository": f"{owner}/{repo_name}","note": "This is the very first issue created in this repository","first_issue": issue_info}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@sub_mcp.tool(tags={"public"})def hello_world() -> str:"""Returns a simple greeting."""return "Hello, world!"mcp.mount("sub_mcp", sub_mcp)if __name__ == "__main__":print("DEBUG: Starting FastMCP GitHub server...")print(f"DEBUG: Server name: {mcp.name}")# Initialize and run the servermcp.run(transport="stdio")Copied
Overwriting gitHub_MCP_server/github_server.py
Hemos sustituído todos los prints por ctx.info. De esta manera, todas esas líneas de información ahora se pueden imprimir en el cliente si queremos.
Más adelante lo vamos a usar
Crear un resource
Vamos a crear un resource estático en nuestro MCP
Servidor MCP
Podemos convertir una función en nuestro servidor en un resource mediante el decorador @mcp.resource(<ENDPOINT>).
Un resource es un endpoint que nos da información. Mientras que una tool puede realizar cambios y/o acciones, un resource solo nos da información.
Vamos a verlo con un ejemplo.
InputPython%%writefile gitHub_MCP_server/github_server.pyimport httpxfrom fastmcp import FastMCP, Contextfrom github import GITHUB_TOKEN, create_github_headersUSER_ID = 1234567890# Create FastMCP servermcp = FastMCP(name="GitHubMCP",instructions="This server provides tools, resources and prompts to interact with the GitHub API.",include_tags={"public"},exclude_tags={"first_issue"})sub_mcp = FastMCP(name="SubMCP",)@mcp.tool(tags={"public", "production"},exclude_args=["user_id"], # user_id has to be injected by server, not provided by LLM)async def list_repository_issues(owner: str, repo_name: str, ctx: Context, user_id: int = USER_ID) -> list[dict]:"""Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')ctx: The context of the requestuser_id: The user ID (automatically injected by the server)Returns:list[dict]: A list of dictionaries, each containing information about an issue"""# Limit to first 10 issues to avoid very long responsesapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=open&per_page=10"ctx.info(f"Fetching issues from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:ctx.info("No open issues found for this repository.")return [{"message": "No open issues found for this repository."}]issues_summary = []for issue in issues_data:# Create a more concise summarysummary = f"#{issue.get('number', 'N/A')}: {issue.get('title', 'No title')}"if issue.get('comments', 0) > 0:summary += f" ({issue.get('comments')} comments)"issues_summary.append({"number": issue.get("number"),"title": issue.get("title"),"user": issue.get("user", {}).get("login"),"url": issue.get("html_url"),"comments": issue.get("comments"),"summary": summary})ctx.info(f"Found {len(issues_summary)} open issues.")# Add context informationresult = {"total_found": len(issues_summary),"repository": f"{owner}/{repo_name}","note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues","issues": issues_summary,"requested_by_user_id": user_id}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"ctx.error(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:ctx.error(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.tool(tags={"private", "development"})async def list_more_repository_issues(owner: str, repo_name: str) -> list[dict]:"""Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list of dictionaries, each containing information about an issue"""# Limit to first 100 issues to avoid very long responsesapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=open&per_page=100"print(f"Fetching issues from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No open issues found for this repository.")return [{"message": "No open issues found for this repository."}]issues_summary = []for issue in issues_data:# Create a more concise summarysummary = f"#{issue.get('number', 'N/A')}: {issue.get('title', 'No title')}"if issue.get('comments', 0) > 0:summary += f" ({issue.get('comments')} comments)"issues_summary.append({"number": issue.get("number"),"title": issue.get("title"),"user": issue.get("user", {}).get("login"),"url": issue.get("html_url"),"comments": issue.get("comments"),"summary": summary})print(f"Found {len(issues_summary)} open issues.")# Add context informationresult = {"total_found": len(issues_summary),"repository": f"{owner}/{repo_name}","note": "Showing first 10 open issues" if len(issues_summary) == 10 else f"Showing all {len(issues_summary)} open issues","issues": issues_summary}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.tool(tags={"public", "first_issue"})async def first_repository_issue(owner: str, repo_name: str) -> list[dict]:"""Gets the first issue ever created in a GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')Returns:list[dict]: A list containing information about the first issue created"""# Get the first issue by sorting by creation date in ascending orderapi_url = f"https://api.github.com/repos/{owner}/{repo_name}/issues?state=all&sort=created&direction=asc&per_page=1"print(f"Fetching first issue from {api_url}...")async with httpx.AsyncClient() as client:try:response = await client.get(api_url, headers=create_github_headers())response.raise_for_status()issues_data = response.json()if not issues_data:print("No issues found for this repository.")return [{"message": "No issues found for this repository."}]first_issue = issues_data[0]# Create a detailed summary of the first issuesummary = f"#{first_issue.get('number', 'N/A')}: {first_issue.get('title', 'No title')}"if first_issue.get('comments', 0) > 0:summary += f" ({first_issue.get('comments')} comments)"issue_info = {"number": first_issue.get("number"),"title": first_issue.get("title"),"user": first_issue.get("user", {}).get("login"),"url": first_issue.get("html_url"),"state": first_issue.get("state"),"comments": first_issue.get("comments"),"created_at": first_issue.get("created_at"),"updated_at": first_issue.get("updated_at"),"body": first_issue.get("body", "")[:500] + "..." if len(first_issue.get("body", "")) > 500 else first_issue.get("body", ""),"summary": summary}print(f"Found first issue: #{first_issue.get('number')} created on {first_issue.get('created_at')}")# Add context informationresult = {"repository": f"{owner}/{repo_name}","note": "This is the very first issue created in this repository","first_issue": issue_info}return [result]except httpx.HTTPStatusError as e:error_message = e.response.json().get("message", "No additional message from API.")if e.response.status_code == 403 and GITHUB_TOKEN:error_message += " (Rate limit with token or token lacks permissions?)"elif e.response.status_code == 403 and not GITHUB_TOKEN:error_message += " (Rate limit without token. Consider creating a .env file with GITHUB_TOKEN.)"print(f"GitHub API error: {e.response.status_code}. {error_message}")return [{"error": f"GitHub API error: {e.response.status_code}","message": error_message}]except Exception as e:print(f"An unexpected error occurred: {str(e)}")return [{"error": f"An unexpected error occurred: {str(e)}"}]@mcp.resource("resource://server_info", tags={"public"})def server_info() -> str:"""Returns information about the server."""return "This is the MCP GitHub server development for MaximoFN blog post"@sub_mcp.tool(tags={"public"})def hello_world() -> str:"""Returns a simple greeting."""return "Hello, world!"mcp.mount("sub_mcp", sub_mcp)if __name__ == "__main__":print("DEBUG: Starting FastMCP GitHub server...")print(f"DEBUG: Server name: {mcp.name}")# Initialize and run the servermcp.run(transport="stdio")Copied
Overwriting gitHub_MCP_server/github_server.py
Como vemos, hemos creado el resource server_info que nos devuelve una cadena de texto con la información del servidor
Es importante ver que hemos declarado el endpoint resource://server_info, que es obligatorio cada vez que creamos resources
Además, le hemos puesto la tag public, ya que nuestro servidor MCP solo incluye las tools o resources que tengan la tag public.
mcp = FastMCP(
name="GitHubMCP",
instructions="This server provides tools, resources and prompts to interact with the GitHub API.",
include_tags={"public"},
exclude_tags={"first_issue"}
)Cliente MCP
Ahora tenemos que hacer que nuestro cliente pueda ver los resources de nuestro servidor MCP.
InputPython%%writefile client_MCP/client.pyimport sysimport asynciofrom contextlib import AsyncExitStackfrom anthropic import Anthropicfrom dotenv import load_dotenvfrom fastmcp import Client# Load environment variables from .env fileload_dotenv()class FastMCPClient:"""FastMCP client that integrates with Claude to process user queriesand use tools and resources exposed by a FastMCP server."""def __init__(self):"""Initialize the FastMCP client with Anthropic and resource management."""self.exit_stack = AsyncExitStack()self.anthropic = Anthropic()self.client = Noneasync def connect_to_server(self, server_script_path: str):"""Connect to the specified FastMCP server.Args:server_script_path: Path to the server script (Python)"""print(f"🔗 Connecting to FastMCP server: {server_script_path}")# Determine the server type based on the extensionif not server_script_path.endswith('.py'):raise ValueError(f"Unsupported server type. Use .py files. Received: {server_script_path}")# Create FastMCP clientself.client = Client(server_script_path)# Note: FastMCP Client automatically infers transport from .py filesprint("✅ Client created successfully")async def list_available_tools(self):"""List available tools in the FastMCP server."""try:# Get list of tools from the server using FastMCP contextasync with self.client as client:tools = await client.list_tools()if tools:print(f" 🛠️ Available tools ({len(tools)}):")print("=" * 50)for tool in tools:print(f"📋 {tool.name}")if tool.description:print(f" Description: {tool.description}")# Show parameters if availableif hasattr(tool, 'inputSchema') and tool.inputSchema:if 'properties' in tool.inputSchema:params = list(tool.inputSchema['properties'].keys())print(f" Parameters: {', '.join(params)}")print()else:print("⚠️ No tools found in the server")except Exception as e:print(f"❌ Error listing tools: {str(e)}")async def list_available_resources(self):"""List available resources in the FastMCP server."""try:# Get list of resources from the server using FastMCP contextasync with self.client as client:resources = await client.list_resources()if resources:print(f" 📚 Available resources ({len(resources)}):")print("=" * 50)for resource in resources:print(f"📄 {resource.uri}")if resource.name:print(f" Name: {resource.name}")if resource.description:print(f" Description: {resource.description}")if resource.mimeType:print(f" MIME Type: {resource.mimeType}")print()else:print("⚠️ No resources found in the server")except Exception as e:print(f"❌ Error listing resources: {str(e)}")async def read_resource(self, resource_uri: str):"""Read a specific resource from the server.Args:resource_uri: URI of the resource to readReturns:str: Resource content"""try:async with self.client as client:result = await client.read_resource(resource_uri)return resultexcept Exception as e:print(f"❌ Error reading resource {resource_uri}: {str(e)}")return Noneasync def process_query(self, query: str) -> str:"""Process a user query, interacting with Claude and FastMCP tools and resources.Args:query: User queryReturns:str: Final processed response"""try:# Use FastMCP context for all operationsasync with self.client as client:# Get available tools and resourcestools_list = await client.list_tools()resources_list = await client.list_resources()# Prepare tools for Claude in correct formatclaude_tools = []for tool in tools_list:claude_tool = {"name": tool.name,"description": tool.description or f"Tool {tool.name}","input_schema": tool.inputSchema or {"type": "object", "properties": {}}}claude_tools.append(claude_tool)# Add a special tool for reading resourcesif resources_list:# Convert URIs to strings to avoid AnyUrl object issuesresource_uris = [str(r.uri) for r in resources_list]claude_tools.append({"name": "read_mcp_resource","description": "Read a resource from the MCP server. Available resources: " +", ".join(resource_uris),"input_schema": {"type": "object","properties": {"resource_uri": {"type": "string","description": "URI of the resource to read"}},"required": ["resource_uri"]}})# Create initial message for Claudemessages = [{"role": "user","content": query}]# First call to Clauderesponse = self.anthropic.messages.create(model="claude-3-5-sonnet-20241022",max_tokens=6000,messages=messages,tools=claude_tools if claude_tools else None)# Process Claude's responseresponse_text = ""for content_block in response.content:if content_block.type == "text":response_text += content_block.textelif content_block.type == "tool_use":# Claude wants to use a tooltool_name = content_block.nametool_args = content_block.inputtool_call_id = content_block.idprint(f"🔧 Claude wants to use: {tool_name}")print(f"📝 Arguments: {tool_args}")try:if tool_name == "read_mcp_resource":# Handle resource readingresource_uri = tool_args.get("resource_uri")if resource_uri:tool_result = await client.read_resource(resource_uri)print(f"📖 Resource read successfully: {resource_uri}")# Better handling of resource resultif hasattr(tool_result, 'content'):# If it's a resource response object, extract contentif hasattr(tool_result.content, 'text'):result_content = tool_result.content.textelse:result_content = str(tool_result.content)else:# If it's already a string or simple objectresult_content = str(tool_result)else:tool_result = "Error: No resource URI provided"result_content = tool_resultelse:# Execute regular tool on the FastMCP servertool_result = await client.call_tool(tool_name, tool_args)print(f"✅ Tool executed successfully")result_content = str(tool_result)# Add tool result to the conversationmessages.append({"role": "assistant","content": response.content})# Format result for Claudeif tool_result:messages.append({"role": "user","content": [{"type": "tool_result","tool_use_id": tool_call_id,"content": f"Tool result: {result_content}"}]})else:messages.append({"role": "user","content": [{"type": "tool_result","tool_use_id": tool_call_id,"content": "Tool executed without response content"}]})# Second call to Claude with the tool resultfinal_response = self.anthropic.messages.create(model="claude-3-5-sonnet-20241022",max_tokens=6000,messages=messages,tools=claude_tools if claude_tools else None)# Extract text from the final responsefor final_content in final_response.content:if final_content.type == "text":response_text += final_content.textexcept Exception as e:error_msg = f"❌ Error executing {tool_name}: {str(e)}"print(error_msg)response_text += f" {error_msg}"return response_textexcept Exception as e:error_msg = f"❌ Error processing query: {str(e)}"print(error_msg)return error_msgasync def chat_loop(self):"""Main chat loop with user interaction."""print(" 🤖 FastMCP client started. Write 'quit', 'q', 'exit', 'salir' to exit.")print("💬 You can ask questions about GitHub repositories!")print("📚 The client can use tools and resources from the FastMCP server")print("-" * 60)while True:try:# Request user inputuser_input = input(" 👤 You: ").strip()if user_input.lower() in ['quit', 'q', 'exit', 'salir']:print("👋 Bye!")breakif not user_input:continueprint(" 🤔 Claude is thinking...")# Process queryresponse = await self.process_query(user_input)# Show responseprint(f" 🤖 Claude: {response}")except KeyboardInterrupt:print(" 👋 Disconnecting...")breakexcept Exception as e:print(f" ❌ Error in chat: {str(e)}")continueasync def cleanup(self):"""Clean up resources and close connections."""print("🧹 Cleaning up resources...")# FastMCP Client cleanup is handled automatically by context managerawait self.exit_stack.aclose()print("✅ Resources released")async def main():"""Main function that initializes and runs the FastMCP client."""# Verify command line argumentsif len(sys.argv) != 2:print("❌ Usage: python client.py <path_to_fastmcp_server>")print("📝 Example: python client.py ../MCP_github/github_server.py")sys.exit(1)server_script_path = sys.argv[1]# Create and run clientclient = FastMCPClient()try:# Connect to the serverawait client.connect_to_server(server_script_path)# List available tools and resources after connectionawait client.list_available_tools()await client.list_available_resources()# Start chat loopawait client.chat_loop()except Exception as e:print(f"❌ Fatal error: {str(e)}")finally:# Ensure resources are cleaned upawait client.cleanup()if __name__ == "__main__":# Entry point of the scriptasyncio.run(main())Copied
Overwriting client_MCP/client.py
Hemos creado los métodos list_available_resources y read_resource para poder leer los recursos que tenemos en el servidor MCP.
Prueba del resource
Ejecutamos el cliente para poder probar el resource que hemos creado
InputPython!cd client_MCP && source .venv/bin/activate && python client.py ../gitHub_MCP_server/github_server.pyCopied
🔗 Connecting to FastMCP server: ../gitHub_MCP_server/github_server.py✅ Client created successfully/Users/macm1/Documents/web/portafolio/posts/gitHub_MCP_server/github_server.py:255: DeprecationWarning: Mount prefixes are now optional and the first positional argument should be the server you want to mount.mcp.mount("sub_mcp", sub_mcp)[06/28/25 11:09:01] INFO Starting MCP server 'GitHubMCP' with transport 'stdio' server.py:1246🛠️ Available tools (2):==================================================📋 sub_mcp_hello_worldDescription: Returns a simple greeting.Parameters:📋 list_repository_issuesDescription: Lists open issues for a given GitHub repository.Args:owner: The owner of the repository (e.g., 'modelcontextprotocol')repo_name: The name of the repository (e.g., 'python-sdk')ctx: The context of the requestuser_id: The user ID (automatically injected by the server)Returns:list[dict]: A list of dictionaries, each containing information about an issueParameters: owner, repo_name📚 Available resources (1):==================================================📄 resource://server_infoName: server_infoDescription: Returns information about the server.MIME Type: text/plain🤖 FastMCP client started. Write 'quit', 'q', 'exit', 'salir' to exit.💬 You can ask questions about GitHub repositories!📚 The client can use tools and resources from the FastMCP server------------------------------------------------------------👤 You: Tell me the server info🤔 Claude is thinking...🔧 Claude wants to use: read_mcp_resource📝 Arguments: {'resource_uri': 'resource://server_info'}📖 Resource read successfully: resource://server_info🤖 Claude: I'll help you read the server information using the `read_mcp_resource` function with the specific resource URI for server info.The server information indicates that this is the MCP GitHub server development environment for MaximoFN blog post.👤 You: q👋 Bye!🧹 Cleaning up resources...✅ Resources released
Vemos que nos da una lista de resources
📚 Available resources (1):
==================================================
📄 resource://server_info
Name: server_info
Description: Returns information about the server.
MIME Type: text/plainY que cuando le pedimos la información del servidor usa el resource server_info que acabamos de crear.
👤 You: Tell me the server info
🤔 Claude is thinking...
🔧 Claude wants to use: read_mcp_resource
📝 Arguments: {'resource_uri': 'resource://server_info'}
📖 Resource read successfully: resource://server_info
🤖 Claude: I'll help you read the server information using the `read_mcp_resource` function with the specific resource URI for server info. The server information indicates that this is the MCP GitHub server development environment for MaximoFN blog post.---
➡️ **Continúa en la Parte 3: resources avanzados y prompts**.