---
title: "Append Sandbox Log"
method: POST
path: "/auto-agent/run/{run_id}/log"
tags: ["auto-agent"]
---

# Append Sandbox Log

`POST /auto-agent/run/{run_id}/log`

Append a log line streamed from inside the sandbox.

Args:
    run_id: Run UUID from the path.
    body: ``{"line": "..."}``.
    callback_token: One-time token issued at run creation.

Raises:
    HTTPException 401: Token invalid or run already finalized.
    HTTPException 404: Run not found.

## Path parameters

- `run_id` string, required

## Headers

- `X-Callback-Token` string, required

## Request body

- SandboxLogRequest — Single log line submitted by the sandbox.
  - `line` string, required — Log line body (timestamp added server-side).

## Response `204`

Successful Response

## Other responses

- `422` — Validation Error

---

[API](https://skmtc.net/pioneer/apis/brain-api.md) · [All operations](https://skmtc.net/pioneer/apis/brain-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/pioneer/brain-api/versions/31dfe831e079/schema)