#4318 @swamp/video: upload workflow to publish a take to YouTube (video, description, chapters, captions, thumbnail)

Problem

Getting a finished take onto YouTube is a manual step. video-render writes <rec>.polished.mp4, the .srt and a 1280x720 thumbnail. video-describe writes the title, description and chapters to youtube.txt and the video-describe data. Then someone opens YouTube Studio and copies each piece in by hand. That's slow and error-prone: chapters get pasted wrong, the thumbnail or captions get forgotten.

Proposed solution

Add a youtube behavior with an upload method, plus a video-publish workflow that runs it after video-describe:

• Auth: OAuth 2.0 for the YouTube Data API v3, with the client secret and refresh token kept in a swamp vault so they stay out of logs and the agent session. A one-time authorize method (or documented steps) gets the refresh token.
• Upload: a resumable videos.insert of <rec>.polished.mp4. Title and description, with chapters, come from the take's video-describe data, wired in with CEL rather than typed again.
• Captions: captions.insert with <rec>.polished.srt.
• Thumbnail: thumbnails.set with <rec>.thumbnail.jpg. This needs a verified channel, so the step should be skipped with a warning when the channel isn't verified.
• Inputs: privacyStatus (default private, also unlisted or public), publishAt for scheduling, playlistId, tags, categoryId, madeForKids (default false).
• Output data: the video id, URL and upload status, so a re-run updates the existing video (videos.update) instead of uploading a duplicate.

Alternatives

• Keep it manual with youtube.txt as the source. That works, but it's the step most likely to go wrong.
• Use a generic shell step around a CLI uploader. That bypasses the data model and vault handling.

Upstream repository: https://github.com/swamp-club/swamp-extensions

Environment

• Extension: @swamp/video@2026.10.30.1
• swamp: 20261102.180642.0-sha.c7a42995
• OS: linux (x86_64)
• Deno: 2.9.8
• Shell: /usr/bin/bash