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 johnlarkin1/claude-code-extensions --skill excalidrawgit clone --depth 1 https://github.com/johnlarkin1/claude-code-extensionsWrote 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/johnlarkin1/claude-code-extensions/excalidraw)<a href="https://agentmods.dev/skills/johnlarkin1/claude-code-extensions/excalidraw"><img src="https://agentmods.dev/badge/skills/johnlarkin1/claude-code-extensions/excalidraw/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/johnlarkin1/claude-code-extensions/excalidraw"><img src="https://agentmods.dev/badge/skills/johnlarkin1/claude-code-extensions/excalidraw.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 | $0.00095 | $0.01285 |
| Opus 5.5 | $0.00038 | $0.00514 |
| Sonnet 5.5 | $0.00019 | $0.00257 |
| Haiku 4.5 | $0.00010 | $0.00128 |
Grade A, and why
excalidraw 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 1mo 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.
The source is not reproduced here
No licence file
A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.
What ships with it
1 file 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.
- 1mo ago First seen · 150 lines · 95 tokens per session scan A 35913521d4d9
excalidraw is a skill published in the GitHub repository johnlarkin1/claude-code-extensions (21 stars, last pushed 2mo ago), with no licence file. It adds 95 tokens to every session and 1,285 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 2026-08-30.
Other skills, from other repositories
design
Generates and maintains a design manifest for visual consistency. In existing projects, reads current styles and documents the design language. In new projects, asks a few questions and generates a starter manifest. The post-edit hook reads the manifest and flags deviations.
doc-pptx
A PowerPoint (.pptx) presentation generator and designer for business reports, investor pitches, training materials, conference talks, and product demos. It can build slides from direct content, HTML, NotebookLM, or a Markdown script.
design-iteration-loop
A repeat-and-review process for improving a design through alternating building and evaluation rounds. It scores design quality, originality, completeness, and whether the result works as intended.
design-landing-motion
A workflow for building animated landing pages, including page concepts, visual assets, and scroll-based effects such as parallax or 3D motion.
design-logo
A brand-aware logo design workflow that reads a project's visual rules, chooses a logo type, and prepares a vector or symbol-based logo request.
design-system-library
A library of 75 brand design systems containing reusable choices for colors, typography, spacing, borders, and interface components. It applies those choices to single-file HTML documents and can provide guidance for Claude Design.