chalk

When self-studying university courses (e.g. CMU 15-411, MIT 6.1810), you often get lecture slides but no lecture videos. The slides alone are rarely self-contained: professors design them as visual aids for a spoken lecture, not as standalone reading material. So you scroll through a PDF, hit a slide you don't understand, and have no way to hear the explanation that was supposed to go with it.

chalk fills that gap. Point it at a lecture PDF, tell it which slides you're stuck on, and it generates a professor-style explanation. It reads all prior slides for context (not just the ones you asked about), so it understands the narrative arc of the lecture before explaining your target slides.

Two ways to use it

Claude Code (recommended)

If you use Claude Code, the /slides skill lets Claude read the slide images directly, no API key needed:

/slides lecture.pdf 15
/slides lecture.pdf 10-15
/slides lecture.pdf 3,7,12 What is the connection between these three slides?

This extracts pages 1 through the last requested page as PNGs, loads them into Claude's context, and explains the target slides with full awareness of everything that came before.

To make /slides available:

chalk --install-skill

Or, if working from a local clone:

mkdir -p ~/.claude/skills/slides
cp skills/slides/SKILL.md ~/.claude/skills/slides/SKILL.md

Standalone CLI

For terminal use without Claude Code. Requires an Anthropic API key:

export ANTHROPIC_API_KEY="sk-ant-..."

chalk lecture.pdf 15
chalk lecture.pdf 3-7
chalk lecture.pdf 1,3,5
chalk lecture.pdf 1-3,5,7-9

The CLI sends all slides from page 1 through your last requested page to Claude's vision API and streams the explanation to stdout.

Options:

--model MODEL       Claude model to use (default: claude-sonnet-4-6)
--prompt PROMPT     Custom prompt (default: "Explain these slides.")
--max-tokens N      Maximum tokens in the response (default: 8192)

Examples:

chalk lecture.pdf 12 --prompt "Summarize the key equations on this slide."
chalk lecture.pdf 1-10 --max-tokens 16384

Installation

Requires Python 3.12+.

# From PyPI
pip install chalk-pypi
# or
uv tool install chalk-pypi

# From source
uv tool install git+https://github.com/fadli0029/chalk.git

Development

git clone https://github.com/fadli0029/chalk.git
cd chalk
uv sync

# Run quality checks
uv run ruff check src/ tests/
uv run ruff format --check src/ tests/
uv run mypy
uv run pytest

License

MIT. See LICENSE.