Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add oaustegard/claude-skills --skill drawing-with-pycairogit clone --depth 1 https://github.com/oaustegard/claude-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/oaustegard/claude-skills/drawing-with-pycairo)<a href="https://agentmods.dev/skills/oaustegard/claude-skills/drawing-with-pycairo"><img src="https://agentmods.dev/badge/skills/oaustegard/claude-skills/drawing-with-pycairo/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/oaustegard/claude-skills/drawing-with-pycairo"><img src="https://agentmods.dev/badge/skills/oaustegard/claude-skills/drawing-with-pycairo.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00109 | $0.02057 |
| Opus 5.5 | $0.00044 | $0.00823 |
| Sonnet 5.5 | $0.00022 | $0.00411 |
| Haiku 4.5 | $0.00011 | $0.00206 |
Grade A, and why
drawing-with-pycairo scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 21d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 102 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Drawing with pycairo
Cairo paints paths with solid colours, gradients, mesh gradients and images, and composites them with 20-odd operators. It writes PNG, PDF, SVG and PostScript. It does not shape text, filter pixels, combine paths, outline strokes, or do depth. scripts/cairokit.py fills each gap; scripts/selftest.py exercises all of it. Both were verified on pycairo 1.29.1 / cairo 1.18.0 / Python 3.11.
Setup
pip install --break-system-packages pycairo numpy uharfbuzz fonttools skia-pathops
python3 /mnt/skills/user/drawing-with-pycairo/scripts/selftest.py /tmp/cairo-selftest
The self-test prints the cairo version, whether Pango is usable, per-panel timings, and the path of a 2×2 contact sheet. Read that sheet: panel A shows joined Arabic in green next to broken toy-API Arabic in red, B shows four boolean results and an outlined wave, C shows glow and a soft shadow, D shows a smooth-shaded torus. Then:
import sys; sys.path.insert(0, "/mnt/skills/user/drawing-with-pycairo/scripts")
from cairokit import *
In the environment where this was built, pycairo was not preinstalled. Pango was also absent: the system PyGObject was compiled for Python 3.12 while python3 was 3.11, and there were no Pango typelibs. pango() reports which case you are in.
Render, then look
Every render ends with a Read of the PNG before the next edit or before reporting. Exit codes and timings don't show visual bugs. In the session that produced this skill, looking caught five defects that ran without error:
- a painter sort drawn near-to-far
- inward normals combined with a light pointing away from the camera, which left a black knot
- a scene scaled in absolute pixels, cropped once the frame size changed
- glyphs crowding on a squashed spiral, because arc length was measured on the unsquashed curve
- a stray hook where a polyline's first
move_towasn't its first sample
For several outputs, contact_sheet() tiles them so one Read covers all of them. For animation, extract two or three frames with ffmpeg -ss T -i out.mp4 -frames:v 1 f.png and read those.
What ships with it
4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 21d ago First seen · 102 lines · 109 tokens per session scan A 3bc996a6ebda
drawing-with-pycairo is a skill published in the GitHub repository oaustegard/claude-skills (153 stars, last pushed yesterday), licensed MIT. It adds 109 tokens to every session and 2,057 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-25.
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