---
title: "Add synthetic message"
method: POST
path: "/api/session/{sessionID}/synthetic"
tags: ["session"]
---

# Add synthetic message

`POST /api/session/{sessionID}/synthetic`

## Request

- Base URL: `https://opencode.ai` (the document declares no server; this is the origin it was published from)
- URL: `https://opencode.ai/api/session/{sessionID}/synthetic`
- Auth: none required

Durably admit synthetic session input and schedule execution unless resume is false.

## Path parameters

- `sessionID` string, required

## Request body

- object
  - `id` string
  - `text` string, required
  - `description` string, nullable
  - `metadata` object
  - `delivery` 'steer' | 'queue'
  - `resume` boolean, nullable

## Response `200`

Success

- object
  - `data` SessionInboxSynthetic, required
    - `id` string, required
    - `sessionID` string, required
    - `time` object, required
      - `created` number, required
    - `type` 'synthetic', required
    - `payload` SessionInboxSyntheticPayload, required
      - `text` string, required
      - `description` string
      - `metadata` object
    - `delivery` 'steer' | 'queue', required

## Other responses

- `400`: InvalidRequestError
- `401`: UnauthorizedError
- `404`: SessionNotFoundError | LocationNotFoundError
- `409`: ConflictError

---

[API](https://skmtc.dev/kaaass/apis/opencode.md) - [All operations](https://skmtc.dev/kaaass/apis/opencode/llms.txt) - [OpenAPI document](https://skmtc.dev/kaaass/apis/opencode/revisions/4e083d954707?raw)