openapi: 3.2.0
info:
  title: Agent Connect Protocol Threads API
  version: 0.2.3
  x-provenance:
    method: harvested
    authored_by: AGNTCY (Outshift by Cisco)
    harvested_by: API Evangelist
    harvested_on: '2026-08-19'
    first_party: true
    provider_published: true
    source_host: agntcy.org / outshift.com
    note: 'Four first-party machine-readable contracts: the Agent Connect Protocol OpenAPI 3.1.1, the OASF Schema API, and two AGNTCY Identity OpenAPI 3.0.3 documents. schema.oasf.outshift.com is the one genuinely callable AGNTCY-hosted API (unauthenticated, 200).'
  x-evidence:
  - type: source
    url: https://spec.acp.agntcy.org/
  - type: source
    url: https://schema.oasf.outshift.com/doc
  - type: source
    url: https://identity-docs.outshift.com/api/openapi/service/v1alpha1/openapi.yaml
  description: "If supported by the involved agents, Run can be grouped in Threads. \nWhen a run is executed on a thread is called Thread Run. At the end of a Thread Run, the server keeps a thread state associated to the thread.\nA thread keeps track of agent states at every step so that continuity of the context is preserved. Moreover, such a book-keeping enables us some granular controls like debugging, interrupting or replaying a run/invocation.\n\nA thread state is a data context defined by the developer and can be anything and it gets passed through from one invocation to another so that business logic is instrumented by data.\n\nA thread keeps track of the whole state history. At every step, it also applies a checkpoint, which is primarily a `uuid`, so that it is easier to refer to a chunk of the history.\n\nOne can easily query the last state, a specific state (by checkpoint id), the whole state history, or, a part of the history (from a checkpoint).\n\nSee `Thread`, `ThreadState` and `Checkpoint` models below for more info."
tags:
- name: Threads
  description: "If supported by the involved agents, Run can be grouped in Threads. \nWhen a run is executed on a thread is called Thread Run. At the end of a Thread Run, the server keeps a thread state associated to the thread.\nA thread keeps track of agent states at every step so that continuity of the context is preserved. Moreover, such a book-keeping enables us some granular controls like debugging, interrupting or replaying a run/invocation.\n\nA thread state is a data context defined by the developer and can be anything and it gets passed through from one invocation to another so that business logic is instrumented by data.\n\nA thread keeps track of the whole state history. At every step, it also applies a checkpoint, which is primarily a `uuid`, so that it is easier to refer to a chunk of the history.\n\nOne can easily query the last state, a specific state (by checkpoint id), the whole state history, or, a part of the history (from a checkpoint).\n\nSee `Thread`, `ThreadState` and `Checkpoint` models below for more info."
paths:
  /threads:
    post:
      tags:
      - Threads
      summary: Create an empty Thread
      description: 'Create a new thread. '
      operationId: create_thread
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ThreadCreate'
        required: true
      responses:
        '200':
          description: Success
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Thread'
        '409':
          description: Conflict
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
  /threads/search:
    post:
      tags:
      - Threads
      summary: Search Threads
      description: 'Search for threads.


        This endpoint also functions as the endpoint to list all threads.'
      operationId: search_threads
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ThreadSearchRequest'
        required: true
      responses:
        '200':
          description: Success
          content:
            application/json:
              schema:
                items:
                  $ref: '#/components/schemas/Thread'
                type: array
                title: Response Search Agents Agents Search Post
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
  /threads/{thread_id}/history:
    get:
      tags:
      - Threads
      summary: Get Thread History
      description: Get all past states for a thread.
      operationId: get_thread_history
      parameters:
      - description: The ID of the thread.
        required: true
        schema:
          type: string
          format: uuid
          title: Thread Id
          description: The ID of the thread.
        name: thread_id
        in: path
      - required: false
        schema:
          type: integer
          title: Limit
          default: 10
        name: limit
        in: query
      - required: false
        schema:
          type: string
          title: Before
        name: before
        in: query
      responses:
        '200':
          description: Success
          content:
            application/json:
              schema:
                items:
                  $ref: '#/components/schemas/ThreadState'
                type: array
        '404':
          description: Not Found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
  /threads/{thread_id}/copy:
    post:
      tags:
      - Threads
      summary: Copy Thread
      description: Create a new thread with a copy of the state and checkpoints from an existing thread.
      operationId: copy_thread
      parameters:
      - description: The ID of the thread.
        required: true
        schema:
          type: string
          format: uuid
          title: Thread Id
          description: The ID of the thread.
        name: thread_id
        in: path
      responses:
        '200':
          description: Success
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Thread'
        '404':
          description: Not Found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
  /threads/{thread_id}:
    parameters:
    - description: The ID of the thread.
      required: true
      schema:
        type: string
        format: uuid
        title: Thread ID
        description: The ID of the thread.
      name: thread_id
      in: path
    get:
      tags:
      - Threads
      summary: Get Thread
      description: 'Get a thread from its ID. '
      operationId: get_thread
      responses:
        '200':
          description: Success
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Thread'
        '404':
          description: Not Found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
    delete:
      tags:
      - Threads
      summary: Delete a thread. If the thread contains any pending run, deletion fails.
      description: Delete a thread.
      operationId: delete_thread
      responses:
        '204':
          description: Success
        '404':
          description: Not Found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
    patch:
      tags:
      - Threads
      summary: Patch Thread
      description: Update a thread.
      operationId: patch_thread
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ThreadPatch'
        required: true
      responses:
        '200':
          description: Success
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Thread'
        '404':
          description: Not Found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
components:
  schemas:
    Message:
      type: object
      properties:
        role:
          type: string
          title: Role
          description: The role of the message.
        content:
          title: Content
          description: The content of the message.
          oneOf:
          - type: string
          - type: array
            items:
              anyOf:
              - type: object
                properties:
                  text:
                    type: string
                  type:
                    const: text
                  metadata:
                    type: object
                required:
                - text
                - type
                title: MessageTextBlock
              - type: object
                properties:
                  type:
                    type: string
                  metadata:
                    type: object
                required:
                - type
                title: MessageAnyBlock
        id:
          type: string
          title: Id
          description: The ID of the message.
        metadata:
          type: object
          title: Metadata
          description: The metadata of the message.
      required:
      - role
      - content
    ThreadStatus:
      type: string
      enum:
      - idle
      - busy
      - interrupted
      - error
    ThreadStateSchema:
      title: Thread State Schema
      description: The thread state. The schema is described in agent ACP descriptor under 'spec.thread_state'.
      oneOf:
      - type: object
        description: 'This object contains an instance of an OpenAPI schema object, formatted as per the OpenAPI specs: https://spec.openapis.org/oas/v3.1.1.html#schema-object'
      - type: string
        description: String thread state to the agent.
      - type: integer
        description: Integer thread state to the agent.
      - type: number
        description: Number thread state to the agent.
      - type: boolean
        description: Boolean thread state to the agent.
      - type: array
        description: Array input to the agent.
        items: {}
    ThreadCheckpoint:
      properties:
        checkpoint_id:
          type: string
          format: uuid
          title: Checkpoint Id
          description: The ID of the checkpoint.
      type: object
      required:
      - checkpoint_id
      title: ThreadCheckpoint
      description: Structured identifier for a thread checkpoint, ie. an entry in the thread's history.
    ThreadSearchRequest:
      properties:
        metadata:
          type: object
          title: Metadata Filter
          description: Matches all threads for which metadata has  keys and values equal to those specified in this object.
        values:
          type: object
          title: Values
          description: State values to filter on.
        status:
          $ref: '#/components/schemas/ThreadStatus'
        limit:
          type: integer
          title: Limit
          description: Maximum number to return.
          default: 10
          minimum: 1
          maximum: 1000
        offset:
          type: integer
          title: Offset
          description: Offset to start from.
          default: 0
          minimum: 0
      type: object
      title: Thread Search Request
      description: Payload for listing threads.
    ErrorResponse:
      type: string
      title: ErrorResponse
      description: Error message returned from the server
    Thread:
      type: object
      title: Thread
      description: Represents a collection of consecutive runs over a thread.  Thread is associated with a state. Runs for a thread can potentially happen across different agents, if the state format is compatible.
      properties:
        thread_id:
          type: string
          title: Thread ID
          description: unique identifier of a thread
        created_at:
          type: string
          format: date-time
          title: Created At
          description: The time the thread was created.
        updated_at:
          type: string
          format: date-time
          title: Updated At
          description: The last time the thread was updated.
        metadata:
          type: object
          title: Metadata
          description: Free form metadata for this thread
        status:
          type: string
          enum:
          - idle
          - busy
          - interrupted
          - error
          title: Status
          description: The status of the thread.
        values:
          title: Values
          description: The current state of the thread.
          $ref: '#/components/schemas/ThreadStateSchema'
        messages:
          type: array
          items:
            $ref: '#/components/schemas/Message'
          title: Messages
          description: The current Messages of the thread. If messages are contained in Thread.values, implementations should remove them from values when returning messages. When this key isn't present it means the thread/agent doesn't support messages.
      required:
      - thread_id
      - created_at
      - updated_at
      - metadata
      - status
    ThreadCreate:
      type: object
      title: Thread
      description: Detail of an empty thread to be created.
      properties:
        thread_id:
          type: string
          format: uuid
          title: Thread Id
          description: The ID of the thread. If not provided, a random UUID will be generated.
        metadata:
          type: object
          title: Metadata
          description: Free form metadata for this thread
        if_exists:
          type: string
          enum:
          - raise
          - do_nothing
          title: If Exists
          description: How to handle duplicate creation. Must be either 'raise' (raise error if duplicate), or 'do_nothing' (return existing thread).
          default: raise
    ThreadPatch:
      properties:
        checkpoint:
          $ref: '#/components/schemas/ThreadCheckpoint'
          title: Checkpoint
          description: The identifier of the checkpoint to branch from. Ignored for metadata-only patches. If not provided, defaults to the latest checkpoint.
        metadata:
          type: object
          title: Metadata
          description: Metadata to merge with existing thread metadata.
        values:
          title: Values
          description: The current state of the thread.
          $ref: '#/components/schemas/ThreadStateSchema'
        messages:
          type: array
          items:
            $ref: '#/components/schemas/Message'
          title: Messages
          description: The current Messages of the thread. If messages are contained in Thread.values, implementations should remove them from values when returning messages. When this key isn't present it means the thread/agent doesn't support messages.
      type: object
      title: ThreadPatch
      description: Payload for updating a thread.
    ThreadState:
      properties:
        checkpoint:
          $ref: '#/components/schemas/ThreadCheckpoint'
          title: Checkpoint
          description: The identifier for this checkpoint.
        values:
          title: Values
          description: The current state of the thread.
          $ref: '#/components/schemas/ThreadStateSchema'
        messages:
          type: array
          items:
            $ref: '#/components/schemas/Message'
          title: Messages
          description: The current messages of the thread. If messages are contained in Thread.values, implementations should remove them from values when returning messages. When this key isn't present it means the thread/agent doesn't support messages.
        metadata:
          type: object
          title: Metadata
          description: The checkpoint metadata.
      type: object
      required:
      - checkpoint
      - values
      title: ThreadState