I work with long talking-head videos for my online course and Instagram. Turning them into vertical shorts used to take hours per video: finding the best moments, cropping to 9:16, adding captions, or paying for clipping subscriptions. I built a video-clipping agent as a Claude skill that runs entirely on free, open-source tools. Step-by-step: 1. I drop a long video—either talking-head footage or an already-produced 16:9 video—into a folder and invoke my "clipper" skill in Claude. 2. Claude transcribes the video locally with faster-whisper using word-level timestamps, so no API key is needed. ElevenLabs Scribe is an optional upgrade for tricky audio. Before transcription, the workflow cleans the audio with declipping and normalization because clipped microphone peaks can make Whisper skip words or hallucinate. 3. The skill scores every candidate moment against a rubric: hook strength (30 points), whether it can stand alone (25), emotional charge (20), rhythm (15), and ending (10). Only segments scoring 70 or higher survive, so I do not publish a weak clip simply because it exists. 4. Claude cuts the selected moments with word-level precision and reframes them to 9:16 in one of two modes: face-tracking crop for raw footage, or "pad" mode, which centers the full 16:9 video over a blurred background. The latter lets me repurpose already-edited videos without chopping off centered graphics or captions. 5. ffmpeg masters everything to a fixed specification: 1080x1920, 24fps, H.264 CRF18, and audio normalized to -14 LUFS. The files are ready for Instagram, TikTok, and Shorts. 6. I review the scored shortlist and publish the winners. What used to take hours—or require a monthly subscription—now takes minutes and costs zero. The scoring rubric also makes the agent explain why each clip deserves to exist instead of simply cutting wherever the waveform looks loud.