Generate timestamps and summaries for YouTube videos.

What it does

The Safari extension adds Chapters and Summary beside YouTube's Transcript and Timeline controls in the native In this video panel. It presents YouTube creator chapters, automatic Key moments, and transcript-generated chapters in one compact format, with a transcript-backed fallback when the native panel is unavailable.

How it works

• The extension detects a supported YouTube watch or live page.
• YouTube creator chapters and automatic Key moments are imported when available.
• The extension fetches the available YouTube transcript for generated results.
• Apple Intelligence can create summaries locally without a provider sign-in.
• A connected ChatGPT or Grok provider can create chapters and model-powered summaries from the transcript.
• The extension validates timestamp candidates against real transcript cue times.
• Native and generated chapter sources can be switched from the Chapters footer when both exist.

Requirements

The app requires Safari on macOS 26.4 or later. Generated chapters and summaries require captions or an available transcript; imported YouTube chapters can display without one. ChatGPT and Grok sign-in are optional. Apple Intelligence is optional for local summaries on compatible Macs. No API key or developer-operated backend is required.