Create MCP Servers

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

• 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

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

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

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

Add server (Python)

claude mcp add --transport stdio
--env API_KEY='${API_KEY}'
-- uv --directory ~/Developer/mcp/ run python -m src.server

Add server (TypeScript)

claude mcp add --transport stdio
--env API_KEY='${API_KEY}'
-- node ~/Developer/mcp//build/index.js

Remove server

claude mcp remove

Check logs

tail -f ~/Library/Logs/Claude/mcp-server-.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:**
```bash
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