> ## Documentation Index
> Fetch the complete documentation index at: https://docs.langchain.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Create a thread run

> Start a run on the thread. This endpoint is proxied to the upstream agent runtime and accepts its run payload. Include the assistant or agent identifier and run inputs in the request body.



## OpenAPI

````yaml /langsmith/managed-deep-agents-openapi.json post /threads/{threadID}/runs
openapi: 3.1.0
info:
  title: Managed Deep Agents API
  version: 0.1.0
  description: Create, configure, and run Managed Deep Agents.
servers:
  - url: https://api.smith.langchain.com/v1/deepagents
security:
  - apiKeyAuth: []
tags:
  - name: Agents
    description: Create and manage Managed Deep Agent resources.
  - name: Threads
    description: Create and inspect durable thread state.
  - name: Runs
    description: Start runs on Managed Deep Agent threads.
  - name: MCP servers
    description: Register MCP servers and store credentials referenced by agent tools.
  - name: MCP tools
    description: List tools exposed by registered MCP servers.
  - name: Auth sessions
    description: Start and poll OAuth authorization sessions for OAuth MCP servers.
paths:
  /threads/{threadID}/runs:
    post:
      tags:
        - Runs
      summary: Create a thread run
      description: >-
        Start a run on the thread. This endpoint is proxied to the upstream
        agent runtime and accepts its run payload. Include the assistant or
        agent identifier and run inputs in the request body.
      operationId: createManagedDeepAgentThreadRun
      parameters:
        - $ref: '#/components/parameters/ThreadID'
      requestBody:
        required: false
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/PassThroughJSON'
      responses:
        '200':
          description: Run returned.
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '201':
          description: Run created.
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '400':
          $ref: '#/components/responses/BadRequest'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '403':
          $ref: '#/components/responses/Forbidden'
        '404':
          $ref: '#/components/responses/NotFound'
        '502':
          $ref: '#/components/responses/BadGateway'
components:
  parameters:
    ThreadID:
      name: threadID
      in: path
      required: true
      description: Thread ID.
      schema:
        type: string
  schemas:
    PassThroughJSON:
      type: object
      description: JSON payload passed through to the upstream agent runtime.
      additionalProperties: true
    ErrorResponse:
      type: object
      properties:
        type:
          type: string
        code:
          type: string
        detail:
          type: string
        status:
          type: integer
  responses:
    BadRequest:
      description: Bad request.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
          examples:
            missingRequiredField:
              summary: Required field missing
              value:
                type: https://docs.langchain.com/errors/missing_required_field
                code: missing_required_field
                detail: 'Set ''name'' to a non-empty string: ''name'' is required'
                status: 400
            invalidRequestBody:
              summary: Malformed JSON body
              value:
                type: https://docs.langchain.com/errors/invalid_request_body
                code: invalid_request_body
                detail: >-
                  Provide a valid JSON request body matching the documented
                  schema
                status: 400
    Unauthorized:
      description: >-
        Authentication required. The auth layer returns a simple `{"error":
        "Unauthorized"}` body that does not match the structured `ErrorResponse`
        shape used by other 4xx responses.
      content:
        application/json:
          schema:
            type: object
            properties:
              error:
                type: string
          examples:
            missingApiKey:
              summary: No `X-Api-Key` header supplied
              value:
                error: Unauthorized
    Forbidden:
      description: >-
        The authenticated identity does not have access to the resource or
        feature. The auth layer returns a simple `{"error": "Forbidden"}` body
        that does not match the structured `ErrorResponse` shape used by other
        4xx responses.
      content:
        application/json:
          schema:
            type: object
            properties:
              error:
                type: string
          examples:
            invalidApiKey:
              summary: API key is invalid or lacks workspace access
              value:
                error: Forbidden
    NotFound:
      description: Resource not found.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
          examples:
            agentNotFound:
              summary: Unknown agent ID
              value:
                type: https://docs.langchain.com/errors/agent_not_found
                code: agent_not_found
                detail: >-
                  Verify the agent ID and that the calling identity has access:
                  agent not found
                status: 404
    BadGateway:
      description: Upstream agent runtime error.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
          examples:
            upstreamAuthFailed:
              summary: >-
                Upstream runtime rejected the request (e.g. orphaned thread
                after agent deletion)
              value:
                type: https://docs.langchain.com/errors/upstream_auth_failed
                code: upstream_auth_failed
                detail: >-
                  Verify that the calling identity is authorized for this
                  organization: upstream agent runtime rejected the request
                status: 502
  securitySchemes:
    apiKeyAuth:
      type: apiKey
      in: header
      name: X-Api-Key
      x-default: LANGSMITH_API_KEY

````