video-summarizer

---
name: "video-summarizer"
description: "Analyzes MP4 files in a directory via the Gemini API and writes a .md summary file next to each video."
license: "MIT"
---

# 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`