# TASK 45 — TEST-tab chat fix #2: insert body must declare `snippet.type`

> Catalog: [`TASKS.md`](../TASKS.md). Status: ✅ **SHIPPED 2026-09-25** — the live
> "YouTube rejected the message (error 400)" report from the creator's Test Stream run
> after TASK 44 shipped.

## Provenance

- **2026-09-25, creator run:** TASK 44's liveChatId fix worked — the drawer opened
  with a resolved liveChatId and Mock Chat Input became enabled — but every send was
  rejected: `YouTube rejected the message (error 400)`. The runtime log
  (`%APPDATA%\ytLlive\startup.log`) captured the body: `400
  MISSING_REQUIRED_FIELD`, `domain: youtube.api.v3.LiveChatMessageInsertResponse.Error`.
- **Diagnosis:** the official `liveChatMessages.insert` reference lists three
  **required** snippet properties: `liveChatId`, **`type`** (`textMessageEvent` or
  `pollEvent`), and `textMessageDetails.messageText` (if text). The TASK 41 body sent
  only `liveChatId` + `textMessageDetails`, omitting `type`. The TASK 41 Good Dog test
  asserted the body contained `liveChatId` + `messageText` — but never `type` — so it
  stayed **false-green** while real YouTube rejected every insert.

## What shipped

- `Services/YouTubeStreamService.cs` — `InsertChatMessageAsync`: the POST body now
  includes **`type = "textMessageEvent"`** in the snippet.
- `ytLive.Tests/TestStreamTests.cs` — the TASK 41 test's POST-body assertion now also
  asserts `"type":"textMessageEvent"` is present (the false-green fixed at its source:
  assertion = WHAT WE SEND must mirror YouTube's required fields).
- Docs: `ai.md` (Test Stream section), `TASKS.md` (row 45), `HANDOFF.md` rewritten,
  `MyMistakes.md` recipe added.

## Validation (Good Dog: ONE integration test)

The strengthened `TestStream_DockTooling_And_ThreeWayDrawerExclusivity` — the existing
TASK 41 insert-to-HTTP assertion now fails if `type` is ever dropped again.

**Gate: clean build 0 warnings; full vstest passed (count recorded in HANDOFF).**

## Reference

- https://developers.google.com/youtube/v3/live/docs/liveChatMessages/insert (required
  props include `snippet.type`; `textMessageEvent` or `pollEvent`)