create-mcp-servers

<objective>

MCP servers extend Claude's capabilities by exposing tools, resources, and prompts. This skill guides creation of production-ready MCP servers with API integrations, OAuth authentication, response optimization, and proper installation in Claude Code and Claude Desktop.

</objective>

<essential_principles>

<the_5_rules>

Every MCP server must follow these:

1. Never Hardcode Secrets - Use ${VAR} expansion in configs, environment variables in code
2. Use cwd Property - Isolates dependencies (not --cwd in args)
3. Always Absolute Paths - which uv to find paths, never relative
4. One Server Per Directory - ~/Developer/mcp/{server-name}/
5. Use uv for Python - Better than pip, handles venvs automatically

</the_5_rules>

<security_checklist>

• Never ask user to paste secrets into chat
• Always use environment variables for credentials
• Use ${VAR} expansion in configs
• Provide exact commands for user to run in terminal
• Verify environment variable existence without showing values
• Never hardcode API keys in code or configs

</security_checklist>

<architecture_decision>

Operation count determines architecture:

• 1-2 operations → Traditional pattern (flat tools)
• 3+ operations → On-demand discovery pattern (meta-tools)

Traditional: Each operation is a separate tool

On-demand: 4 meta-tools (discover, get_schema, execute, continue) + operations.json

</architecture_decision>

<context>

MCP servers expose:

• Tools: Functions Claude can call (API requests, file operations, calculations)
• Resources: Data Claude can read (files, database records, API responses)
• Prompts: Reusable prompt templates with arguments

Standard location: ~/Developer/mcp/{server-name}/

</context>

</essential_principles>

<routing>

Based on user intent, route to appropriate workflow:

No context provided (skill invoked without description):

Use AskUserQuestion:

• header: "Mode"
• question: "What would you like to do?"
• options:
• "Create a new MCP server" → workflows/create-new-server.md
• "Update an existing MCP server" → workflows/update-existing-server.md
• "Troubleshoot a server" → workflows/troubleshoot-server.md

Context provided (user described what they want):

Route directly to workflows/create-new-server.md

</routing>

<workflows_index>

| Workflow | Purpose |

|----------|---------|

| create-new-server.md | Full 8-step workflow from intake to verification |

| update-existing-server.md | Modify or extend an existing server |

| troubleshoot-server.md | Diagnose and fix connection/runtime issues |

</workflows_index>

<templates_index>

| Template | Purpose |

|----------|---------|

| python-server.py | Traditional pattern starter for Python |

| typescript-server.ts | Traditional pattern starter for TypeScript |

| operations.json | On-demand discovery operations definition |

</templates_index>

<scripts_index>

| Script | Purpose |

|--------|---------|

| setup-python-project.sh | Initialize Python MCP project with uv |

| setup-typescript-project.sh | Initialize TypeScript MCP project with npm |

</scripts_index>

<references_index>

Core workflow:

• creation-workflow.md - Complete step-by-step with exact commands

Architecture patterns:

• traditional-pattern.md - For 1-2 operations (flat tools)
• large-api-pattern.md - For 3+ operations (on-demand discovery)

Language-specific:

• python-implementation.md - Async patterns, type hints
• typescript-implementation.md - Type safety, SDK features

Advanced topics:

• oauth-implementation.md - OAuth with stdio isolation
• response-optimization.md - Field truncation, pagination
• tools-and-resources.md - Resources API, prompts, streaming
• testing-and-deployment.md - Unit tests, packaging, publishing
• validation-checkpoints.md - All validation checks
• adaptive-questioning-guide.md - Question templates for intake
• api-research-template.md - API research document format

</references_index>

<quick_reference>

# List servers
claude mcp list

# Add server (Python)
claude mcp add --transport stdio <name> \
  --env API_KEY='${API_KEY}' \
  -- uv --directory ~/Developer/mcp/<name> run python -m src.server

# Add server (TypeScript)
claude mcp add --transport stdio <name> \
  --env API_KEY='${API_KEY}' \
  -- node ~/Developer/mcp/<name>/build/index.js

# Remove server
claude mcp remove <name>

# Check logs
tail -f ~/Library/Logs/Claude/mcp-server-<name>.log

# Find paths
which uv && which node && which python

</quick_reference>

<troubleshooting_quick>

Server not appearing: Check claude mcp list, verify config in ~/.claude/settings.json

"command not found": Use absolute paths from which uv / which node

Environment variable not found:

echo $MY_API_KEY  # Check if set
echo 'export MY_API_KEY="value"' >> ~/.zshrc && source ~/.zshrc

Secrets visible in conversation: STOP. Delete conversation. Rotate credentials. Never paste secrets in chat.

Full troubleshooting: workflows/troubleshoot-server.md

</troubleshooting_quick>

<success_criteria>

A production-ready MCP server has:

• Valid configuration in Claude Code (claude mcp list shows ✓ Connected)
• Valid configuration in Claude Desktop config
• Environment variables set securely in ~/.zshrc
• Architecture matches operation count
• OAuth stdio isolation if applicable
• Response optimization for list/search operations
• All validation checkpoints passed
• No errors in logs

</success_criteria>