---
title: "Provider-neutral control plane for hosted ALK harness jobs."
method: POST
path: "/simulate/api/harness-jobs/{id}/conversation/messages/"
tags: ["simulate"]
---

# Provider-neutral control plane for hosted ALK harness jobs.

`POST /simulate/api/harness-jobs/{id}/conversation/messages/`

## Request

- Base URL: `http://localhost:8000`
- URL: `http://localhost:8000/simulate/api/harness-jobs/{id}/conversation/messages/`
- Auth: one of:
  - API key in header `X-Api-Key`
  - API key in header `X-Secret-Key`

Validates the v1.6 request contract and delegates execution to the public backend selected by
``settings.HARNESS_PROVIDER`` (``hosted`` or ``sandbox``). The hosted backend independently
selects its managed sandbox runtime.

## Request body

- HarnessConversationMessageCreate
  - `content` string, required
  - `client_request_id` string, required
  - `kind` 'user_message' | 'user_response' | 'approval' | 'interrupt' | 'cancel_operation'
  - `reply_to` string, uuid, nullable
  - `payload` object

## Response `202`

Accepted

- HarnessConversationRead, nullable
  - `conversation_id` string, uuid, required
  - `job_id` string, uuid, required
  - `state` string, required
  - `stage` string, required
  - `active_invocation_id` string, nullable, required
  - `blocking_input` object, nullable, required
  - `messages` HarnessConversationMessage[], required
    - `message_id` string, uuid, required
    - `sequence` integer, required
    - `role` 'user' | 'assistant' | 'system', required
    - `kind` 'message' | 'question' | 'confirmation' | 'status', required
    - `state` 'queued' | 'delivered' | 'streaming' | 'completed' | 'failed', required
    - `stage` string, required
    - `content` string, required
    - `payload` object, required
    - `invocation_id` string, nullable
    - `function_call_id` string, nullable
    - `reply_to` string, uuid, nullable
    - `created_at` string, date-time, required
  - `events` HarnessConversationEventRead[], required
    - `event_id` string, required
    - `sequence` integer, required
    - `kind` string, required
    - `message_id` string, uuid, nullable
    - `stage` string, required
    - `invocation_id` string, nullable
    - `function_call_id` string, nullable
    - `payload` object, required
    - `emitted_at` string, date-time, required
  - `event_watermark` integer, required
  - `runtime` HarnessConversationRuntime, required
    - `state` string, required
    - `warm_until` string, date-time, nullable, required
    - `degraded` boolean, required
    - `available` boolean, required

## Other responses

- `409`: Conflict
- `default`: Default error response

---

[API](https://skmtc.dev/futureagi/apis/future-agi-management-api.md) · [All operations](https://skmtc.dev/futureagi/apis/future-agi-management-api/llms.txt) · [OpenAPI document](https://skmtc.dev/futureagi/apis/future-agi-management-api/revisions/c8684118e142?raw)