---
title: "Stream a thread run"
method: POST
path: "/v1/fleet/threads/{thread_id}/runs/stream"
tags: ["fleet threads"]
---

# Stream a thread run

`POST /v1/fleet/threads/{thread_id}/runs/stream`

Start a run on a thread and stream its output as Server-Sent Events. The connection stays open until the run completes; the client is responsible for closing it.

## Path parameters

- `thread_id` string, required

## Request body

- ThreadsStreamRunRequest
  - `agent_id` string, uuid
  - `messages` ThreadsMessage[]
    - `content` string
    - `role` 'user' | 'assistant' | 'system' | 'tool'
  - `stream_mode` string[]
  - `stream_subgraphs` boolean
  - `user_timezone` string

## Response `200`

SSE event stream

- string

## Other responses

- `400` — Bad Request
- `401` — Unauthorized
- `403` — Forbidden
- `404` — Not Found
- `502` — Bad Gateway

---

[API](https://skmtc.net/langchain-ai/apis/langsmith.md) · [All operations](https://skmtc.net/langchain-ai/apis/langsmith/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/langchain-ai/langsmith/revisions/a0acb3a6a101/schema)