Video Summarizer

---
name: video-summarizer
description: >
  Analyzes local MP4 video files using the Gemini API and generates structured Markdown summaries.
  Supports custom prompts to extract specific information instead of the default summary.
  Use when the user wants to summarize, analyze, or extract key points from video files in bulk.
  Triggers on requests like "summarize my videos", "create markdown summaries for the videos",
  "analyze videos with Gemini", "generate video summaries", or "extract X from my videos".
  Requires GEMINI_API_KEY environment variable set in the system.
---

# Video Summarizer

Analyzes MP4 files in a directory via the Gemini API and writes a `.md` summary file next to each video.

## Prerequisites

- `GEMINI_API_KEY` env var must be set
- `google-genai` installed: `py -m pip install google-genai`
- Python available as `py` (Windows) or `python3`

## Workflow

### 1. Determine the prompt

Check if the user provided a custom prompt or specific extraction instructions.

- **No custom prompt** -> use the default (structured summary with Title, Summary, Key Points, Takeaways)
- **User provides custom instructions** -> pass them via `--prompt` or `--prompt-file`

A custom prompt **completely replaces** the default. Examples of custom prompts:
- "Extract all mentioned tools, their prices, and a one-line description for each"
- "List every action item and deadline mentioned in this video"
- "Create a transcript outline with timestamps"

### 2. Run the script

```bash
# Default summary — all videos in current directory (recursive)
py scripts/summarize_videos.py

# Default summary — specific directory
py scripts/summarize_videos.py "C:/path/to/videos"

# Custom prompt (inline) — replaces default summary format
py scripts/summarize_videos.py --prompt "Extract all product names and prices mentioned"

# Custom prompt (from file) — replaces default summary format
py scripts/summarize_videos.py --prompt-file my-prompt.txt

# Both directory and custom prompt
py scripts/summarize_videos.py "C:/path/to/videos" --prompt "List all key decisions made"
```

### 3. How Claude should handle user arguments

When the user invokes this skill:

1. If the user specifies a **custom prompt or extraction goal** (e.g., "extract all tools mentioned",
   "summarize focusing on pricing", "list action items"), pass it via `--prompt "..."`.
2. If the user provides a **prompt file path**, pass it via `--prompt-file path/to/file.txt`.
3. If the user gives **no specific instructions**, run without `--prompt` to use the default format.
4. If the user specifies a **directory**, pass it as the first positional argument.

### 4. Default output format (when no custom prompt is given)

```markdown
# [Video Title]

## Summary
[2-3 sentence description]

## Key Points
- point 1
- point 2
- ...

## Core Content & Takeaways
[Central message and key insight]

---
*Auto-generated with Gemini API*
```

## Notes

- Language of the summary matches the language of the video
- Files are auto-deleted from Gemini storage after processing (48h limit)
- Already-summarized videos are skipped on re-runs
- Script path: `scripts/summarize_videos.py`
- Model: `gemini-3-flash-preview`