registry/docs/server-registry-api
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Filename Latest commit message Latest commit date
Tadas Antanavicius 05422afffb
Split OpenAPI specs into base and official registry versions (#171)
Closes #149

As noted in the FAQ update here, this is a helpful starting point in
thinking about this:

```
### What is the difference between "Official MCP Registry", "MCP Registry", "MCP registry", "MCP Registry API", etc?

There are four underlying concepts:
- "MCP Server Registry API" (or "MCP Registry API"): The OpenAPI specification defined in [openapi.yaml](./server-registry-api/openapi.yaml). This is a reusable API specification that anyone building any sort of "MCP server registry" should consider adopting / aligning with.
- "Official MCP Registry" (or "MCP Registry"): The application that lives at `https://registry.modelcontextprotocol.io`. This registry currently only catalogs MCP servers, but may be extended in the future to also catalog MCP client/host apps and frameworks.
- "Official MCP Registry API": The REST API that lives at `https://registry.modelcontextprotocol.io/api`, with an OpenAPI specification defined at [official-registry-openapi.yaml](./server-registry-api/official-registry-openapi.yaml)
- "MCP server registry" (or "MCP registry"): A third party, likely commercial, implementation of the MCP Server Registry API or derivative specification.
```

Prior to this PR, we were just treating "MCP Server Registry API" and
"Official MCP Registry API" to be the same thing. They are not the same:
the latter is inherently a more constrained version of the former. A
private deployment of a similar registry need not have constraints like
"the only valid source code repositories are `github` and `gitlab`".

This PR separates out the definitions to match that path forward.

## Notable Changes

### Base OpenAPI spec (`openapi.yaml`)
- Removed official-registry-specific constraints:
  - No maximum limit on `/servers` endpoint
  - No enum constraint on `Repository.source`
  - No enum constraint on `Package.registry_name`
- Removed `/v0` prefix from paths (it's now just baked into the
`official` one's URL prefix)
- Added `$id` for proper schema identification

### Official Registry OpenAPI spec (`official-registry-openapi.yaml`)
- Created as a derivative of the base spec using `$ref`
- Re-adds official-registry-specific constraints:
  - `Repository.source` enum: `[github]`
  - `Package.registry_name` enum: `[npm, docker, pypi, nuget]`

### Documentation updates
- Added `server-registry-api/README.md` explaining the relationship
between specs
- Updated FAQ to clarify terminology
- Reorganized docs structure
2025-07-10 00:46:01 +00:00
..
examples.md Split OpenAPI specs into base and official registry versions (#171) 2025-07-10 00:46:01 +00:00
official-registry-openapi.yaml Split OpenAPI specs into base and official registry versions (#171) 2025-07-10 00:46:01 +00:00
openapi.yaml Split OpenAPI specs into base and official registry versions (#171) 2025-07-10 00:46:01 +00:00
README.md Split OpenAPI specs into base and official registry versions (#171) 2025-07-10 00:46:01 +00:00

Registry API

There are a variety of use cases where an MCP Server Registry API is useful to the MCP ecosystem. At least the following:

  • Implementation of a centralized, publicly available catalog of all publicly accessible MCP server implementations
  • Implementation of a private catalog of MCP server implementations exclusively accessible by a specific group of people (e.g. a single enterprise)

These scenarios would benefit from a standard "MCP server registry API" specification that they could potentially compose, as well as share resources (like SDK implementations).

The centralized, publicly available catalog ("Official MCP Registry") needs additional constraints that need not apply to the broader "MCP server registry API"

References:

  • openapi.yaml - A reusable API specification (MCP Server Registry API) that anyone building any sort of "MCP server registry" should consider adopting / aligning with.
  • examples.md - Example manifestations of the OpenAPI specification
  • official-registry-openapi.ayml - The specification backing the Official MCP Registry; a derivative of the MCP Server Registry API specification.