> ## Documentation Index > Fetch the complete documentation index at: https://docs.agentsfleet.net/llms.txt > Use this file to discover all available pages before exploring further. # Post a message to the event's thread > Posts one line to the thread the leased event came from, before the run answers, with the fleet's secret values masked. The daemon holds the channel's credential and posts; the runner sends text. A run may post at most 8 messages, refused past that with `UZ-RUN-020`. An event from no thread, such as an API steer, a webhook or a schedule, is refused with `UZ-RUN-019`. Both are 409s naming their `current_state`. `delivered` is false when the channel refused the line, or stayed unreachable through every retry within 12 seconds. Takes no `Idempotency-Key`: each line is its own post. ## OpenAPI ````yaml https://raw.githubusercontent.com/agentsfleet/agentsfleet/main/public/openapi.json post /v1/runners/me/leases/{lease_id}/messages openapi: 3.1.0 info: title: agentsfleet Control Plane API description: API for managing workspaces, fleets, triggers, and runs. contact: name: agentsfleet url: https://agentsfleet.net license: name: MIT identifier: MIT version: 1.0.0 servers: - url: https://api.agentsfleet.net description: Production security: [] paths: /v1/runners/me/leases/{lease_id}/messages: post: tags: - Runners summary: Post a message to the event's thread description: >- Posts one line to the thread the leased event came from, before the run answers, with the fleet's secret values masked. The daemon holds the channel's credential and posts; the runner sends text. A run may post at most 8 messages, refused past that with `UZ-RUN-020`. An event from no thread, such as an API steer, a webhook or a schedule, is refused with `UZ-RUN-019`. Both are 409s naming their `current_state`. `delivered` is false when the channel refused the line, or stayed unreachable through every retry within 12 seconds. Takes no `Idempotency-Key`: each line is its own post. operationId: runner_post_message parameters: - name: lease_id in: path description: '`UUIDv7` of the lease.' required: true schema: type: string requestBody: content: application/json: schema: $ref: '#/components/schemas/MessageRequest' required: true responses: '200': description: OK content: application/json: schema: $ref: '#/components/schemas/MessagePosted' '400': description: The request could not be read content: application/problem+json: schema: $ref: '#/components/schemas/ProblemBody' '401': description: No credential, or one this route does not accept content: application/problem+json: schema: $ref: '#/components/schemas/ProblemBody' '403': description: The credential is good and lacks the capability this route requires content: application/problem+json: schema: $ref: '#/components/schemas/ProblemBody' '404': description: No such resource, or none this caller may see content: application/problem+json: schema: $ref: '#/components/schemas/ProblemBody' '409': description: The request conflicts with the resource's current state content: application/problem+json: schema: $ref: '#/components/schemas/ProblemBody' '413': description: The payload is over this route's ceiling content: application/problem+json: schema: $ref: '#/components/schemas/ProblemBody' '429': description: The instance is at its ceiling content: application/problem+json: schema: $ref: '#/components/schemas/ProblemBody' '500': description: The daemon failed to answer content: application/problem+json: schema: $ref: '#/components/schemas/ProblemBody' '503': description: A dependency this route needs is unreachable content: application/problem+json: schema: $ref: '#/components/schemas/ProblemBody' security: - RunnerBearerAuth: [] components: schemas: MessageRequest: type: object description: '`POST /v1/runners/me/leases/{lease_id}/messages` request.' required: - fencing_token - text properties: fencing_token: type: integer format: int64 description: >- The lease's fencing token; a holder the fleet has superseded is refused. minimum: 0 text: type: string description: What to say in the thread. At most 4096 bytes. maxLength: 4096 minLength: 1 additionalProperties: false MessagePosted: type: object description: What posting a message did. required: - delivered properties: delivered: type: boolean description: >- Whether the thread has the message. `false` when the channel refused it or stayed unreachable through every retry; the run goes on, and the report still carries the answer. Beta: this field may change shape before it is stable. x-stability: beta ProblemBody: type: object description: The body every refusal carries, under `application/problem+json`. required: - docs_uri - title - detail - error_code - request_id properties: action_id: type: - string - 'null' description: 'On that 409 only: the action the gate held.' current_state: type: - string - 'null' description: 'On a 409 only: the state that forbade the transition.' detail: type: string description: One sentence on what was refused and why. docs_uri: type: string description: Where the error code is documented. error_code: type: string description: The registry code, stable across releases. etag: type: - string - 'null' description: >- On a 412 only: the resource's current entity tag, to refetch and retry. gate_id: type: - string - 'null' description: 'On an answered approval gate''s 409 only: the gate that was answered.' outcome: type: - string - 'null' description: 'On that 409 only: the answer that stands.' request_id: type: string description: The request this refusal answers, for support. resolved_at: type: - integer - 'null' format: int64 description: 'On that 409 only: when the standing answer was given.' resolved_by: type: - string - 'null' description: 'On that 409 only: who gave it.' title: type: string description: A short name for the refusal, safe to show a person. user_message: type: - string - 'null' description: A curated sentence for end users, where the code has one. securitySchemes: RunnerBearerAuth: type: http scheme: bearer bearerFormat: agt_r description: The opaque agt_r token minted when the runner enrols (POST /v1/runners) ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.