Supported formats
MCP Blacksmith accepts OpenAPI specifications in:
Have a Postman Collection or Google Discovery document instead? You can convert them to OpenAPI using postman-to-openapi or google-discovery-to-openapi, then upload the result.
Support for additional API specification formats is planned, including GraphQL, gRPC (Protocol Buffers), AsyncAPI, RAML, and API Blueprint.
How to upload
In the dashboard:- Create a new project
- Drag and drop your specification file into the upload zone, or click to browse
- MCP Blacksmith parses and validates the specification immediately
Where to find specifications
Most APIs publish their OpenAPI specification. Common locations:- API documentation pages — Look for “OpenAPI”, “Swagger”, or “API Reference” links
- Common URL patterns —
/openapi.json,/swagger.json,/api-docs,/v3/api-docs - GitHub repositories — Many companies publish specifications in their public repos
- Public registries — SwaggerHub or APIs.guru
Specification quality tips
While any valid specification should result in a fully functional server, better specifications produce better servers:- Include descriptions — These become tool descriptions for AI agents
- Define security schemes — Authentication handlers are auto-generated
- Use component schemas — Shared references produce deduplicated models
- Specify response schemas — Enables response validation at runtime