# MCP Builder

> Design, build, configure, or debug Model Context Protocol servers for codewhale, including stdio and HTTP/SSE transports.

- Skill: `gabrielmoreira/mcp-builder-3` (Agent Skill)
- Install (CLI): `npx skillmds@latest add gabrielmoreira/mcp-builder-3`
- Raw SKILL.md: https://api.skillmd.com/api/skills/gabrielmoreira/mcp-builder-3/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: gabrielmoreira (https://skillmd.com/u/gabrielmoreira)
- Updated: 2026-09-21
- Page: https://skillmd.com/skills/gabrielmoreira/mcp-builder-3

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# MCP Builder

Use this skill when the user asks to create, configure, or debug an MCP server
or tool integration.

## Design Rules

- Prefer stdio MCP servers for local tools and HTTP/SSE for remote services.
- Keep tool schemas small, typed, and explicit. Return structured JSON where
  possible.
- Put secrets in environment variables, never in committed config.
- For HTTP/SSE clients, send `Accept: application/json, text/event-stream` by
  default unless the server explicitly requires something else.
- Add timeouts and clear error messages around external APIs.

## Codewhale Setup

Common commands:

```bash
codewhale mcp init
codewhale mcp add my-server --command node --arg server.js
codewhale mcp add remote-server --url http://127.0.0.1:3000/mcp
codewhale mcp list
codewhale mcp validate
codewhale mcp tools
```

HTTP/SSE entries can include per-server headers in `~/.codewhale/mcp.json` when
credentials or custom routing headers are required.

## Workflow

1. Define the service boundary and the minimum useful tools.
2. Choose transport and credential handling.
3. Implement the server using a maintained MCP SDK when available.
4. Add the server with `codewhale mcp add` or edit `~/.codewhale/mcp.json`.
5. Run `codewhale mcp validate`, then `codewhale mcp tools`.
6. Test one happy path and one failure path before calling it done.