Agent-Skills.md

Agent Skills: Converting MCP Servers to Skills

Connect to MCP (Model Context Protocol) servers and create skills for repeated use. Load when a user wants to use an MCP server, connect to external tools via MCP, or when they mention MCP, model context protocol, or specific MCP servers.

UncategorizedID: letta-ai/letta-code/converting-mcps-to-skills

Repository

letta-ai/letta-code
letta-aiLicense: Apache-2.0
992125

Install this agent skill to your local

pnpm dlx add-skill https://github.com/letta-ai/letta-code/tree/HEAD/src/skills/builtin/converting-mcps-to-skills

Skill Files

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src/skills/builtin/converting-mcps-to-skills/SKILL.md

Skill Metadata

Name
converting-mcps-to-skills
Description
Connect to MCP (Model Context Protocol) servers and create skills for repeated use. Load when a user wants to use an MCP server, connect to external tools via MCP, or when they mention MCP, model context protocol, or specific MCP servers.

Converting MCP Servers to Skills

Letta Code is not itself an MCP client, but as a general computer-use agent, you can easily connect to any MCP server using the scripts in this skill.

What is MCP?

MCP (Model Context Protocol) is a standard for exposing tools to AI agents. MCP servers provide tools via JSON-RPC, either over:

  • HTTP - Server running at a URL (e.g., http://localhost:3001/mcp)
  • stdio - Server runs as a subprocess, communicating via stdin/stdout

Quick Start: Connecting to an MCP Server

Step 1: Determine the transport type

Ask the user:

  • Is it an HTTP server (has a URL)?
  • Is it a stdio server (runs via command like npx, node, python)?

Step 2: Test the connection

For HTTP servers:

npx tsx <skill-path>/scripts/mcp-http.ts <url> list-tools

# With auth header
npx tsx <skill-path>/scripts/mcp-http.ts <url> --header "Authorization: Bearer KEY" list-tools

For stdio servers:

# First, install dependencies (one time)
cd <skill-path>/scripts && npm install

# Then connect
npx tsx <skill-path>/scripts/mcp-stdio.ts "<command>" list-tools

# Examples
npx tsx <skill-path>/scripts/mcp-stdio.ts "npx -y @modelcontextprotocol/server-filesystem ." list-tools
npx tsx <skill-path>/scripts/mcp-stdio.ts "python server.py" list-tools

Step 3: Explore available tools

# List all tools
... list-tools

# Get schema for a specific tool
... info <tool-name>

# Test calling a tool
... call <tool-name> '{"arg": "value"}'

Creating a Dedicated Skill

When an MCP server will be used repeatedly, create a dedicated skill for it. This makes future use easier and documents the server's capabilities.

Decision: Simple vs Rich Skill

Simple skill (just SKILL.md):

  • Good for straightforward servers
  • Documents how to use the parent skill's scripts with this specific server
  • No additional scripts needed

Rich skill (SKILL.md + scripts/):

  • Good for frequently-used servers
  • Includes convenience wrapper scripts with defaults baked in
  • Provides a simpler interface than the generic scripts

See references/skill-templates.md for templates.

Built-in Scripts Reference

mcp-http.ts - HTTP Transport

Connects to MCP servers over HTTP. No dependencies required.

npx tsx mcp-http.ts <url> [options] <command> [args]

Commands:
  list-tools              List available tools
  list-resources          List available resources
  info <tool>             Show tool schema
  call <tool> '<json>'    Call a tool

Options:
  --header "K: V"         Add HTTP header (repeatable)
  --timeout <ms>          Request timeout (default: 30000)

Examples:

# Basic usage
npx tsx mcp-http.ts http://localhost:3001/mcp list-tools

# With authentication
npx tsx mcp-http.ts http://localhost:3001/mcp --header "Authorization: Bearer KEY" list-tools

# Call a tool
npx tsx mcp-http.ts http://localhost:3001/mcp call vault '{"action":"search","query":"notes"}'

mcp-stdio.ts - stdio Transport

Connects to MCP servers that run as subprocesses. Requires npm install first.

# One-time setup
cd <skill-path>/scripts && npm install

npx tsx mcp-stdio.ts "<command>" [options] <action> [args]

Actions:
  list-tools              List available tools
  list-resources          List available resources
  info <tool>             Show tool schema
  call <tool> '<json>'    Call a tool

Options:
  --env "KEY=VALUE"       Set environment variable (repeatable)
  --cwd <path>            Set working directory
  --timeout <ms>          Request timeout (default: 30000)

Examples:

# Filesystem server
npx tsx mcp-stdio.ts "npx -y @modelcontextprotocol/server-filesystem ." list-tools

# With environment variable
npx tsx mcp-stdio.ts "node server.js" --env "API_KEY=xxx" list-tools

# Call a tool
npx tsx mcp-stdio.ts "python server.py" call read_file '{"path":"./README.md"}'

Common MCP Servers

Here are some well-known MCP servers:

| Server | Transport | Command/URL | |--------|-----------|-------------| | Filesystem | stdio | npx -y @modelcontextprotocol/server-filesystem <path> | | GitHub | stdio | npx -y @modelcontextprotocol/server-github | | Brave Search | stdio | npx -y @modelcontextprotocol/server-brave-search | | obsidian-mcp-plugin | HTTP | http://localhost:3001/mcp |

Troubleshooting

"Cannot connect" error:

  • For HTTP: Check the URL is correct and server is running
  • For stdio: Check the command works when run directly in terminal

"Authentication required" error:

  • Add --header "Authorization: Bearer YOUR_KEY" for HTTP
  • Or --env "API_KEY=xxx" for stdio servers that need env vars

stdio "npm install" error:

  • Run cd <skill-path>/scripts && npm install first
  • The stdio client requires the MCP SDK

Tool call fails:

  • Use info <tool> to see the expected input schema
  • Ensure JSON arguments match the schema