---
title: "Create a message."
method: POST
path: "/v0/sessions/{sessionId}/messages"
tags: ["Workspaces"]
---

# Create a message.

`POST /v0/sessions/{sessionId}/messages`

## Request

- Base URL: `https://api.conductor.build` (the document declares no server; this is the origin it was published from)
- URL: `https://api.conductor.build/v0/sessions/{sessionId}/messages`
- Auth: HTTP bearer

Sends a user message to the session's agent. To attach files (up to 10), upload each one with POST /v0/sessions/{sessionId}/attachments and list the attachment ids in attachments. The agent is told to read the attached files, which appear in the workspace under .context/attachments/. To retry a message whose response was lost, resend it with the same messageId, text, and attachments. Attachments are in preview and enabled per user; requests from users without access receive 403.

## Path parameters

- `sessionId` string, required

## Query parameters

- `channel` 'prod' | 'alpha' | 'alpha-chromium' | 'beta' | 'patch' | 'dev' | 'funhouse'

## Request body

- object
  - `messageId` string, uuid
  - `message` string, required
  - `source` object
    - `kind` 'slack', required
    - `url` string, uri, required
    - `label` string
  - `attachments` object[]
    - `id` string, uuid, required

## Response `201`

Default Response

- object
  - `messageId` string, required
  - `state` union, required
    - 'queued'
    - 'sent'
  - `deepLink` string, required

## Other responses

- `400`: Invalid request.
- `401`: Missing or invalid bearer token.
- `404`: Resource not found.
- `default`: Error response.

---

[API](https://skmtc.dev/conductor-build/apis/roundhouse-public-api.md) - [All operations](https://skmtc.dev/conductor-build/apis/roundhouse-public-api/llms.txt) - [OpenAPI document](https://skmtc.dev/conductor-build/apis/roundhouse-public-api/revisions/1f39c7f7f219?raw)