---
title: "Changes to Send Video Agent Message"
method: POST
path: "/v3/video-agents/{session_id}"
---

# Changes to Send Video Agent Message

`POST /v3/video-agents/{session_id}`

> Every recorded change to this operation, newest first.

## Timeline

Changed in 1 of 2 revisions.

- **2026-11-03** `7dfa5e59b4f5`: 17 info

## Changes

- **2026-11-03** `7dfa5e59b4f5`: 17 info
  - added the new optional `header` request parameter `Idempotency-Key`
  - added the new optional request property `edit_plan`
  - added `subschema #1, subschema #2` to the request body `anyOf` list
  - the request property `message` became optional
  - the `message` request property default value `` was added
  - added `asset_id, base64, url` discriminator mapping keys to the `files/anyOf[subschema #1]/items/` request property
  - the `message` request property's minLength was decreased from `1` to `0`
  - added the non-success response with the status `409`
  - added the optional property `data/video_id` to the response with the `200` status
  - added the optional property `error/errors` to the response with the `400` status
  - added the optional property `error/errors` to the response with the `401` status
  - added the optional property `error/errors` to the response with the `404` status
  - added the optional property `error/errors` to the response with the `429` status
  - added the optional property `error/request_id` to the response with the `400` status
  - added the optional property `error/request_id` to the response with the `401` status
  - added the optional property `error/request_id` to the response with the `404` status
  - added the optional property `error/request_id` to the response with the `429` status

---

[Operation](https://skmtc.dev/heygen/apis/heygen-external-api/docs/v3/video-agents/:session_id/post.md) - [API](https://skmtc.dev/heygen/apis/heygen-external-api.md) - [Page](https://skmtc.dev/heygen/apis/heygen-external-api/changes/v3/video-agents/:session_id/post)