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

# Send a message to an existing Microsoft Teams chat as the calling member

> Sends one message to an existing Teams chat. The operation cannot create a new chat.



## OpenAPI

````yaml /openapi.json post /v1/capabilities/microsoft-365/teams-chats/{chatId}/messages
openapi: 3.1.0
info:
  title: Den API
  description: >-
    OpenAPI spec for the Den control plane API.


    Authentication:

    - Use `Authorization: Bearer <session-token>` for user-authenticated routes
    that require a Den session.

    - Use `x-api-key: <den-api-key>` for API-key-authenticated routes that
    accept organization API keys.

    - Public routes like health and documentation do not require authentication.


    Swagger tip: use the security schemes in the Authorize dialog to set either
    `bearerAuth` or `denApiKey` before trying protected endpoints.
  version: dev
servers: []
security: []
tags:
  - name: System
    description: Service health and operational routes.
  - name: Organizations
    description: Top-level organization creation and context routes.
  - name: Invitations
    description: Invitation preview, acceptance, creation, and cancellation routes.
  - name: API Keys
    description: Organization API key management routes.
  - name: SCIM
    description: Organization SCIM connector management routes.
  - name: SSO
    description: Organization single sign-on connector management routes.
  - name: Members
    description: Organization member management routes.
  - name: Roles
    description: Organization custom role management routes.
  - name: Teams
    description: Organization team management routes.
  - name: Templates
    description: Organization shared template routes.
  - name: LLM Providers
    description: Organization LLM provider catalog, configuration, and access routes.
  - name: Skills
    description: Organization skill authoring and sharing routes.
  - name: Skill Hubs
    description: Organization skill hub management and access routes.
  - name: Workers
    description: Worker lifecycle, billing, and runtime routes.
  - name: Worker Runtime
    description: Worker runtime inspection and upgrade routes.
  - name: Worker Activity
    description: Worker heartbeat and activity reporting routes.
  - name: Telemetry
    description: Telemetry event ingestion and adoption analytics.
  - name: Admin
    description: Administrative reporting routes.
  - name: Users
    description: Current user and membership routes.
  - name: Bootstrap
    description: Agent-first provisional workspace setup routes.
paths:
  /v1/capabilities/microsoft-365/teams-chats/{chatId}/messages:
    post:
      tags:
        - Capability Sources
      summary: Send a message to an existing Microsoft Teams chat as the calling member
      description: >-
        Sends one message to an existing Teams chat. The operation cannot create
        a new chat.
      operationId: postV1CapabilitiesMicrosoft365TeamsChatsByChatIdMessages
      parameters:
        - $ref: '#/components/parameters/Microsoft365TeamsChatParams'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Microsoft365TeamsMessageBody'
      responses:
        '200':
          description: Teams chat message sent.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Microsoft365TeamsMessageResponse'
        '401':
          description: The caller must be signed in.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/UnauthorizedError'
        '409':
          description: >-
            The calling member has not connected their Microsoft account or is
            missing permission.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Microsoft365NeedsConnectionError'
        '502':
          description: Microsoft Graph rejected the request.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Microsoft365GraphError'
components:
  parameters:
    Microsoft365TeamsChatParams:
      in: path
      name: chatId
      schema:
        type: string
        minLength: 1
        maxLength: 1024
      required: true
  schemas:
    Microsoft365TeamsMessageBody:
      type: object
      properties:
        content:
          type: string
          minLength: 1
          maxLength: 20000
      required:
        - content
    Microsoft365TeamsMessageResponse:
      type: object
      properties:
        ok:
          type: boolean
          const: true
        message:
          $ref: '#/components/schemas/Microsoft365TeamsMessage'
      required:
        - ok
        - message
    UnauthorizedError:
      type: object
      properties:
        error:
          type: string
          const: unauthorized
      required:
        - error
    Microsoft365NeedsConnectionError:
      type: object
      properties:
        error:
          type: string
          const: needs_connection
        message:
          type: string
      required:
        - error
        - message
    Microsoft365GraphError:
      type: object
      properties:
        error:
          type: string
          const: microsoft_graph_error
        message:
          type: string
      required:
        - error
        - message
    Microsoft365TeamsMessage:
      type: object
      properties:
        id:
          type: string
        createdDateTime:
          type: string
        content:
          type: string
        from:
          anyOf:
            - $ref: '#/components/schemas/Microsoft365EmailAddress'
            - type: 'null'
        webUrl:
          type: string
      required:
        - id
        - createdDateTime
        - content
        - from
        - webUrl
    Microsoft365EmailAddress:
      type: object
      properties:
        name:
          type: string
        address:
          type: string
      required:
        - name
        - address

````