MCP Builder Skill

Production-ready MCP (Model Context Protocol) servers that connect Claude to external APIs, databases, and services—built with agent-first design principles.

When to Use

Connecting Claude to external APIs (Stripe, GitHub, Slack, etc.)
Creating database access tools (PostgreSQL, MongoDB, MySQL)
Building custom business logic tools
Enabling workflow automation through integrated services

Key Capabilities

Capability	Python (FastMCP)	TypeScript (MCP SDK)
Tool Registration	`@mcp.tool` decorator	`server.registerTool`
Input Validation	Pydantic v2 models	Zod schemas
Async Operations	Native async/await	Promise-based
Type Safety	Type hints	TypeScript strict mode
Best For	Data/ML/scientific	API wrappers/web services

Core Features:

Agent-optimized workflow tools (not just API wrappers)
Context-aware responses (concise vs. detailed)
Actionable error messages that guide usage
Pagination, rate limiting, character limits (25K tokens)
Read-only, destructive, idempotent tool hints

Common Use Cases

Payment Processing Integration

Who: SaaS developer adding billing

"Use mcp-builder to create Stripe MCP server with:
- Create customer and subscription
- Process payments
- Manage invoices
- Handle webhooks
- List transactions"

Project Management Automation

Who: Team lead integrating dev tools

"Use mcp-builder for GitHub + Jira MCP server:
- Sync issues between platforms
- Create PRs from Jira tickets
- Track commit status
- Send Slack notifications"

Database Operations

Who: Backend developer building admin tools

"Use mcp-builder for PostgreSQL MCP server with:
- Execute queries safely
- Schema introspection
- Read-only mode
- Character limit truncation
- Pagination support"

Custom Business Logic

Who: Startup automating workflows

"Use mcp-builder to create invoice generation MCP server:
- Calculate taxes
- Generate PDF invoices
- Send email notifications
- Update accounting records"

Multi-Service Integration

Who: Full-stack developer building AI assistant

"Use mcp-builder to combine Slack, Google Calendar, and Notion:
- Schedule meetings
- Send team updates
- Create task lists
- Sync across platforms"

Development Workflow

Phase	Action
1. Research	Study MCP docs, API docs, design agent-first workflows
2. Plan	Select high-impact tools, define input/output schemas
3. Implement	Build shared utilities, implement tools with validation
4. Review	Check DRY, type safety, error handling, documentation
5. Evaluate	Create 10 complex questions to test tool effectiveness

Testing: Use evaluation harness or tmux (servers run indefinitely on stdio/stdin).

Pro Tips

Design for workflows, not endpoints: Combine operations (e.g., check availability + schedule event)
Optimize context: Default to concise responses, provide detailed option when needed
Write actionable errors: Suggest next steps (“Try filter=‘active_only’”)
Use consistent prefixes: Group related tools (e.g., github_*, stripe_*)
Load docs as needed: MCP protocol, SDK docs, language-specific guides
Create evaluations: 10 complex, read-only questions to verify tool quality
Not activating? Say: “Use mcp-builder skill to…”

Configuration

Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "my-server": {
      "command": "node",
      "args": ["/absolute/path/to/dist/index.js"],
      "env": {
        "API_KEY": "your-api-key"
      }
    }
  }
}

Python: Use python /path/to/server.py as command TypeScript: Use node /path/to/dist/index.js after npm run build

MCP Management - Install and manage MCP servers
Databases - PostgreSQL/MongoDB integration
Backend Development - API design patterns
Planning - Design complex integrations

Use MCP Builder to create production-ready servers that connect Claude to any external service. Follows agent-first design principles with workflow-focused tools, context optimization, and comprehensive evaluation harnesses for quality assurance.