registry/docs/server-registry-api/openapi.yaml
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

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YAML

openapi: 3.1.0
jsonSchemaDialect: "https://json-schema.org/draft/2020-12/schema"
$id: https://modelcontextprotocol.io/schemas/draft/2025-07-09/server-registry-openapi
info:
title: MCP Server Registry API
summary: API for discovering and accessing MCP server metadata
description: |
Specification for a theoretical REST API that serves up metadata about MCP servers.
license:
name: MIT
identifier: MIT
paths:
/servers:
get:
summary: List MCP servers
description: Returns a list of all registered MCP servers
parameters:
- name: limit
in: query
description: Number of results per page
schema:
type: integer
minimum: 1
- name: offset
in: query
description: Number of results to skip for pagination
schema:
type: integer
default: 0
minimum: 0
responses:
'200':
description: A list of MCP servers
content:
application/json:
schema:
$ref: '#/components/schemas/ServerList'
/servers/{id}:
get:
summary: Get MCP server details
description: Returns detailed information about a specific MCP server
parameters:
- name: id
in: path
required: true
description: Unique ID of the server
schema:
type: string
format: uuid
- name: version
in: query
description: Desired MCP server version
schema:
type: string
responses:
'200':
description: Detailed server information
content:
application/json:
schema:
$ref: '#/components/schemas/ServerDetail'
'404':
description: Server not found
content:
application/json:
schema:
type: object
properties:
error:
type: string
example: "Server not found"
components:
schemas:
Repository:
type: object
required:
- url
- source
- id
properties:
url:
type: string
format: uri
example: "https://github.com/modelcontextprotocol/servers"
source:
type: string
example: "github"
id:
type: string
example: "b94b5f7e-c7c6-d760-2c78-a5e9b8a5b8c9"
Server:
type: object
required:
- id
- name
- description
- version_detail
properties:
id:
type: string
format: uuid
example: "a5e8a7f0-d4e4-4a1d-b12f-2896a23fd4f1"
name:
type: string
description: Human-readable description of the server's functionality
example: "io.modelcontextprotocol/filesystem"
description:
type: string
example: "Node.js server implementing Model Context Protocol (MCP) for filesystem operations."
repository:
$ref: '#/components/schemas/Repository'
version_detail:
$ref: '#/components/schemas/VersionDetail'
VersionDetail:
type: object
required:
- version
- release_date
- is_latest
properties:
version:
type: string
example: "1.0.2"
description: Equivalent of Implementation.version in MCP specification.
release_date:
type: string
format: date-time
example: "2023-06-15T10:30:00Z"
description: Datetime that the MCP server version was published to the registry.
is_latest:
type: boolean
example: true
description: Whether the MCP server version is the latest version available in the registry.
ServerList:
type: object
required:
- servers
- total_count
properties:
servers:
type: array
items:
$ref: '#/components/schemas/Server'
next:
type: string
format: uri
example: "https://registry.modelcontextprotocol.io/servers?offset=50"
total_count:
type: integer
example: 1
Package:
type: object
required:
- registry_name
- name
- version
properties:
registry_name:
type: string
description: Package registry type
example: "npm"
name:
type: string
description: Package name in the registry
example: "io.modelcontextprotocol/filesystem"
version:
type: string
description: Package version
example: "1.0.2"
runtime_hint:
type: string
description: A hint to help clients determine the appropriate runtime for the package. This field should be provided when `runtime_arguments` are present.
examples: [npx, uvx, dnx]
runtime_arguments:
type: array
description: A list of arguments to be passed to the package's runtime command (such as docker or npx). The `runtime_hint` field should be provided when `runtime_arguments` are present.
items:
$ref: '#/components/schemas/Argument'
package_arguments:
type: array
description: A list of arguments to be passed to the package's binary.
items:
$ref: '#/components/schemas/Argument'
environment_variables:
type: array
description: A mapping of environment variables to be set when running the package.
items:
$ref: '#/components/schemas/KeyValueInput'
Input:
type: object
properties:
description:
description: A description of the input, which clients can use to provide context to the user.
type: string
is_required:
type: boolean
default: false
format:
type: string
description: |
Specifies the input format. Supported values include `filepath`, which should be interpreted as a file on the user's filesystem.
When the input is converted to a string, booleans should be represented by the strings "true" and "false", and numbers should be represented as decimal values.
enum: [string, number, boolean, filepath]
default: string
value:
type: string
description: |
The default value for the input. If this is not set, the user may be prompted to provide a value. If a value is set, it should not be configurable by end users.
Identifiers wrapped in `{curly_braces}` will be replaced with the corresponding properties from the input `variables` map. If an identifier in braces is not found in `variables`, or if `variables` is not provided, the `{curly_braces}` substring should remain unchanged.
is_secret:
type: boolean
description: Indicates whether the input is a secret value (e.g., password, token). If true, clients should handle the value securely.
default: false
default:
type: string
description: The default value for the input.
choices:
type: array
description: A list of possible values for the input. If provided, the user must select one of these values.
items:
type: string
example: []
InputWithVariables:
allOf:
- $ref: '#/components/schemas/Input'
- type: object
properties:
variables:
type: object
description: A map of variable names to their values. Keys in the input `value` that are wrapped in `{curly_braces}` will be replaced with the corresponding variable values.
additionalProperties:
$ref: '#/components/schemas/Input'
PositionalArgument:
description: A positional input is a value inserted verbatim into the command line.
allOf:
- $ref: '#/components/schemas/InputWithVariables'
- type: object
required:
- type
- value_hint
properties:
type:
type: string
enum: [positional]
example: "positional"
value_hint:
type: string
description: An identifier-like hint for the value. This is not part of the command line, but can be used by client configuration and to provide hints to users.
example: file_path
is_repeated:
type: boolean
description: Whether the argument can be repeated multiple times in the command line.
default: false
NamedArgument:
description: A command-line `--flag={value}`.
allOf:
- $ref: '#/components/schemas/InputWithVariables'
- type: object
required:
- type
- name
properties:
type:
type: string
enum: [named]
example: "named"
name:
type: string
description: The flag name, including any leading dashes.
example: "--port"
is_repeated:
type: boolean
description: Whether the argument can be repeated multiple times.
default: false
KeyValueInput:
allOf:
- $ref: '#/components/schemas/InputWithVariables'
- type: object
required:
- name
properties:
name:
type: string
description: Name of the header or environment variable.
example: SOME_VARIABLE
Argument:
anyOf:
- $ref: '#/components/schemas/PositionalArgument'
- $ref: '#/components/schemas/NamedArgument'
Remote:
type: object
required:
- transport_type
- url
properties:
transport_type:
type: string
enum: [streamable, sse]
description: Transport protocol type
example: "sse"
url:
type: string
format: uri
description: Remote server URL
example: "https://mcp-fs.example.com/sse"
headers:
type: array
description: HTTP headers to include
items:
$ref: '#/components/schemas/KeyValueInput'
ServerDetail:
description: Schema for a static representation of an MCP server. Used in various contexts related to discovery, installation, and configuration.
allOf:
- $ref: '#/components/schemas/Server'
- type: object
properties:
packages:
type: array
items:
$ref: '#/components/schemas/Package'
remotes:
type: array
items:
$ref: '#/components/schemas/Remote'