MCP Builder

What it does

MCP Builder helps turn a service API into tools an AI client can discover and call through Model Context Protocol. The work includes tool boundaries, typed inputs, authentication, pagination and useful errors. It is most valuable when a model needs repeatable access to a system rather than a pasted export. The skill covers both TypeScript and Python and treats task-based evaluation as part of server development.

When to use it

• Expose read-only stock lookup from an inventory API without handing the agent a general-purpose administrator connection.
• Connect an internal knowledge service with explicit search and document retrieval tools.
• Replace vague tool descriptions and unbounded responses in an existing MCP integration.

Step-by-step workflow

1. Read the service API and current MCP documentation. Identify authentication, rate limits, pagination and the operations users actually need.
2. Select an SDK version and transport appropriate to the client. The reviewed source separates TypeScript v2 from legacy v1 and distinguishes local stdio from remote HTTP. Do not mix examples across SDK versions.
3. Define descriptive tool names, constrained input schemas and structured results. Ensure large datasets can be filtered or paginated.
4. Implement the service client, authentication handling and actionable errors. Separate read operations from writes and keep granted permissions narrow.
5. Build and validate tool calls, then create evaluations based on realistic user tasks. Check whether the client can complete the task from the returned data.

Example request

Use mcp-builder to create a read-only inventory integration. Support product search by name and stock lookup by product ID. Use the API specification in docs/inventory-api.md. Return paginated results and distinguish unknown products from API outages. Keep tokens in environment variables, exclude write endpoints and provide a local smoke command plus task-based evaluations for exact matches, multiple matches and no matches.

Worked example

A stock tool should return the product identity, location and available quantity with enough context to interpret the number. A timeout should become an explicit service error rather than zero stock. Search needs pagination so a large catalogue does not consume the entire agent context. These choices make the integration useful even before adding more endpoints.

What you get

An MCP server implementation, tool definitions and task-oriented validation.

How to evaluate the result

• Expect server source, dependency metadata, tool schemas, configuration instructions and a repeatable smoke check. Include the credential variable names without secret values.
• Exercise valid input, malformed input, no results, expired credentials and upstream errors. Verify writes cannot be reached through a supposedly read-only integration.
• Evaluate an end-to-end question using the actual client. Successful compilation alone says little about tool discoverability or answer quality.

What you need

An API specification, supported SDK runtime and service credentials when required.

Setup and activation

The publisher README documents Claude Code’s anthropic-agent-skills marketplace and its example-skills plugin. After reviewing the selected source and bundled files, enable the appropriate plugin in your client and mention the skill by name. Keep the complete skill folder so relative references still resolve. Plugin availability and commands depend on the client version; the publisher README is linked below. This page installs nothing. Before local installation, review and security-scan the exact source/version; catalogue inclusion is not security approval.

Limits and considerations

If a supported connector already solves the task, use it before building a server. MCP does not grant permission to access private data or make a tool safe by itself. Hosting, credentials and third-party API usage may carry separate costs.

Related workflows

• Pair with Agents SDK App Builder when an app needs these service tools.
• Keep service-specific authorization tests alongside protocol checks.

License and reuse

Apache License 2.0, confirmed in this skill’s LICENSE.txt. Reuse remains subject to the license’s notice and other requirements; inspect the exact version and any separately licensed assets.

Further reading

• Publisher setup and repository README
• Skill-specific license