---
title: "Activate a thread sandbox"
method: POST
path: "/v1/fleet/threads/{thread_id}/sandbox-activation"
tags: ["fleet threads"]
---

# Activate a thread sandbox

`POST /v1/fleet/threads/{thread_id}/sandbox-activation`

## Request

- Base URL: `https://api.smith.langchain.com`
- URL: `https://api.smith.langchain.com/v1/fleet/threads/{thread_id}/sandbox-activation`
- Auth: one of:
  - API key in header `X-API-Key`
  - API key in header `X-Tenant-Id`
  - HTTP bearer

Starts or resumes the sandbox referenced by the thread and returns when it is ready. The operation is idempotent. The thread must include sandbox.sandbox_slug.

## Path parameters

- `thread_id` string, uuid, required

## Response `200`

OK

- ThreadsSandboxRef
  - `sandbox_slug` string, required
  - `scope` 'agent' | 'thread', required
  - `status` 'provisioning' | 'ready' | 'failed' | 'stopped' | 'deleting', required

## Other responses

- `400`: Bad Request
- `403`: Forbidden
- `404`: Not Found
- `409`: Conflict
- `501`: Not Implemented

## Changes

- **2026-10-16** `1a8ee9358d81`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/langchain-ai/apis/langsmith/changes/v1/fleet/threads/:thread_id/sandbox-activation/post.md)

---

[API](https://skmtc.dev/langchain-ai/apis/langsmith.md) - [All operations](https://skmtc.dev/langchain-ai/apis/langsmith/llms.txt) - [OpenAPI document](https://skmtc.dev/langchain-ai/apis/langsmith/revisions/7a01c01f75e8?raw)