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 anton-abyzov/vskill --skill excalidraw-mcpgit clone --depth 1 https://github.com/anton-abyzov/vskillWrote 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/anton-abyzov/vskill/excalidraw-mcp)<a href="https://agentmods.dev/skills/anton-abyzov/vskill/excalidraw-mcp"><img src="https://agentmods.dev/badge/skills/anton-abyzov/vskill/excalidraw-mcp/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/anton-abyzov/vskill/excalidraw-mcp"><img src="https://agentmods.dev/badge/skills/anton-abyzov/vskill/excalidraw-mcp.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Prompt Injection · line 69 This pattern attempts to override system instructions or ignore safety constraints. Without LLM analysis, manual review is recommended.Fix: Remove or rewrite any text that instructs the agent to ignore prompts, override safety rules, or trust unverified content. Ensure skill content cannot be injected to alter agent behavior.
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 | $0.00146 | $0.02713 |
| Opus 5 | $0.00073 | $0.01357 |
| Sonnet 5 | $0.00029 | $0.00543 |
| Haiku 4.5 | $0.00015 | $0.00271 |
Grade A, and why
excalidraw-mcp 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 6d 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 — 187 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Excalidraw via MCP
Saying "use Excalidraw MCP" should be enough to get a complicated diagram, drawn live and saved where it belongs. This skill is what makes that true.
The one thing that breaks everything
create_view's element format is a skeleton, not the on-disk schema. A shape's
label is skeleton-only sugar. Excalidraw's canvas renderer has no text branch for
rectangle / ellipse / diamond — container text is drawn only via
boundElements → containerId. So pasting create_view JSON into a .excalidraw file
produces empty boxes, silently. That single fact is why scripts/excalidraw_build.py
exists: author once in the skeleton, get both the live render and a correct file.
Second fact: hand-authored diagrams do not degrade gradually with size — they fail on irregularity. Measured on a real generated scene, elements produced by a repeating layout formula had a 0.00 defect rate; bespoke one-off elements had 0.71. So compute positions with a formula, and let the linter check the result.
Preflight on a new machine
Installing this skill does not install the MCP server — mcp-deps is a declaration
that vskill check verifies, not an installer. If the mcp__excalidraw__* tools are
not available, run this first — it detects and registers the server, on any OS:
python3 scripts/ensure_mcp.py --install
It reports where the server was found, or runs
claude mcp add --transport http --scope user excalidraw https://mcp.excalidraw.com
and re-verifies. Exit 0 configured, 1 missing, 2 could not register (no Claude CLI on
PATH — it prints the command to run by hand). Claude Code needs a restart afterwards to
pick up a newly added server.
Scopes: --scope user (default) covers every project on the machine via ~/.claude.json;
--scope project writes ./.mcp.json so teammates get it on clone; --scope local is
this project only. A server registered under a different project counts as missing —
Claude Code will not load it here, and the script says so.
What ships with it
13 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.
- .gitignore 29 B
- examples/specweave-lifecycle.excalidraw 28 KB
- examples/specweave-lifecycle.excalidraw.md 20 KB
- examples/specweave-lifecycle.skeleton.json 3.2 KB
- references/file-format.md 4.6 KB
- references/layout-recipes.md 4.2 KB
- references/mcp-workflow.md 3.9 KB
- references/obsidian.md 2.2 KB
- scripts/ensure_mcp.py 6.4 KB runs code
- scripts/excalidraw_build.py 21 KB runs code
- scripts/excalidraw_lint.py 14 KB runs code
- scripts/excalidraw_render.py 4.2 KB runs code
- scripts/split_excalidraw_library.py 5.4 KB runs code
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.
- 6d ago First seen · 187 lines · 146 tokens per session scan A 079d58cd0006
excalidraw-mcp is a skill published in the GitHub repository anton-abyzov/vskill (45 stars, last pushed 3d ago), licensed MIT. It adds 146 tokens to every session and 2,713 once invoked, about $0.0007 per session on Opus 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 2026-09-03.
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