Agentcard Authentication API

openapi: 3.1.0
info:
  title: Agentcard Authentication API
  version: 2.0.0
  description: The Agentcard v2 API — connect your users and verify their identity from your own backend. Every call is authenticated with a platform access token minted from your `client_id` + `client_secret`.
servers:
- url: https://api.agentcard.sh
  description: There is one base URL. Sandbox vs production is decided by the client credential you use, never by the host.
security:
- platformToken: []
tags:
- name: Authentication
  description: Exchange your client credentials for a platform access token, and introspect what a token acts as.
paths:
  /api/v2/oauth/token:
    post:
      tags:
      - Authentication
      summary: Create an access token
      operationId: createAccessToken
      security: []
      description: 'Exchanges your `client_id` + `client_secret` for a platform access token (OAuth2 client credentials, RFC 6749 §4.4). The token lives one hour — when it expires, exchange again; there are no refresh tokens on this grant.


        Get your credentials in the Agentcard dashboard under **Organization → Developer → Credentials**. A sandbox client mints tokens that act in sandbox; a production client acts in production.


        You can also send the credentials as HTTP Basic (`Authorization: Basic base64(client_id:client_secret)`) instead of in the form body.


        This endpoint is rate limited to 30 requests per 5 minutes per IP — cache the token and reuse it until it expires.'
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              type: object
              required:
              - grant_type
              - client_id
              - client_secret
              properties:
                grant_type:
                  type: string
                  enum:
                  - client_credentials
                  description: Always `client_credentials`.
                client_id:
                  type: string
                  description: Your client id, from the dashboard.
                client_secret:
                  type: string
                  description: Your client secret (`acs_…`), shown once when you create the client.
      responses:
        '200':
          description: 'The token to send as `Authorization: Bearer <access_token>` on every other call.'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TokenResponse'
              example:
                access_token: eyJhbGciOiJIUzI1NiIs…
                token_type: Bearer
                expires_in: 3600
                scope: api
        '400':
          description: '`unsupported_grant_type` — the `grant_type` isn''t `client_credentials`. `unauthorized_client` — the client can''t use this grant.'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/OAuthError'
              example:
                error: unsupported_grant_type
                error_description: Only grant_type=client_credentials is supported here
        '401':
          description: '`invalid_client` — unknown client or bad credentials.'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/OAuthError'
              example:
                error: invalid_client
                error_description: Unknown client or bad credentials
        '403':
          description: '`access_denied` — the organization is suspended.'
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/OAuthError'
              example:
                error: access_denied
                error_description: Organization is suspended
  /api/v2:
    get:
      tags:
      - Authentication
      summary: Introspect credential
      operationId: introspectCredential
      description: Returns the organization and mode your token acts as. Useful as a health check and to confirm you're pointed at the right credential.
      responses:
        '200':
          description: The organization and mode behind the token.
          content:
            application/json:
              schema:
                type: object
                properties:
                  object:
                    type: string
                    enum:
                    - api_v2
                  organization_id:
                    type: string
                    description: The organization the token belongs to.
                  mode:
                    type: string
                    enum:
                    - sandbox
                    - production
                    description: Decided by the client the token was minted from.
              example:
                object: api_v2
                organization_id: org_a1b2c3
                mode: sandbox
        '401':
          $ref: '#/components/responses/Unauthorized'
components:
  schemas:
    Error:
      type: object
      description: Every v2 error uses the same envelope.
      properties:
        error:
          type: object
          properties:
            code:
              type: string
              description: A stable, machine-readable string (snake_case). Branch on this.
            message:
              type: string
              description: A human-readable explanation, safe to log.
            docs:
              type: string
              description: A link back to the reference.
            field_errors:
              type: object
              additionalProperties:
                type: string
              description: Only on `invalid_fields` — names each field to fix.
            warnings:
              type: array
              items:
                type: string
              description: Only on document upload errors — actionable feedback safe to show the user.
    TokenResponse:
      type: object
      properties:
        access_token:
          type: string
          description: 'The platform access token. Send it as `Authorization: Bearer <access_token>` on every other endpoint.'
        token_type:
          type: string
          enum:
          - Bearer
        expires_in:
          type: integer
          description: Seconds until the token expires (3600 = one hour).
        scope:
          type: string
          enum:
          - api
    OAuthError:
      type: object
      description: RFC 6749 §5.2 error shape — only the token endpoint uses it.
      properties:
        error:
          type: string
          description: A stable, machine-readable code.
        error_description:
          type: string
          description: A human-readable explanation.
  responses:
    Unauthorized:
      description: '`unauthorized` — the platform access token is missing or expired. Exchange your client credentials for a fresh one.'
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  securitySchemes:
    platformToken:
      type: http
      scheme: bearer
      description: 'A platform access token. Get one on the **Create an access token** endpoint by exchanging your `client_id` + `client_secret`, then send it as `Authorization: Bearer <token>`. Tokens live one hour.'