fix-mermaid

fix-mermaid is a skill for Claude Code from rp1-run/rp1. It costs 32 tokens per session (343 once invoked), scanned A, original, Apache-2.0.

A tool for checking and repairing Mermaid diagrams embedded in Markdown files. Mermaid is a text format that turns diagram instructions into visual charts.

In plain words
What is it for?
Use it on a Markdown file or diagram from standard input. It scans every Mermaid block, validates each one, and tries up to three repairs.
Why use it?
It finds syntax errors that can stop diagrams from rendering and automatically fixes common problems. Diagrams it cannot repair are marked with placeholders.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the rp1-base plugin — 20 skills, 17 agents, 1 hook shipped together

Good fit Use it on a Markdown file or diagram from standard input. It scans every Mermaid block, validates each one, and tries up to three repairs.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/rp1-run/rp1/fix-mermaid
Install

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.

Any agent
npx skills add rp1-run/rp1 --skill fix-mermaid
Clone the repo
git clone --depth 1 https://github.com/rp1-run/rp1

Made for: Claude Code.

Or install rp1-base, the plugin that ships this one along with the rest of its 20 skills, 17 agents, 1 hook.

Wrote 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.

agentmods badge for fix-mermaid

README.md
[![agentmods](https://agentmods.dev/badge/skills/rp1-run/rp1/fix-mermaid/github.svg)](https://agentmods.dev/skills/rp1-run/rp1/fix-mermaid)
Your own site
<a href="https://agentmods.dev/skills/rp1-run/rp1/fix-mermaid"><img src="https://agentmods.dev/badge/skills/rp1-run/rp1/fix-mermaid/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.

agentmods 80×15 button for fix-mermaid

Your own site · 80×15
<a href="https://agentmods.dev/skills/rp1-run/rp1/fix-mermaid"><img src="https://agentmods.dev/badge/skills/rp1-run/rp1/fix-mermaid.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 32 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 343 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00032 $0.00343
Opus 5 $0.00016 $0.00171
Sonnet 5 $0.00006 $0.00069
Haiku 4.5 $0.00003 $0.00034

Measured 12d ago against content hash 1c7c388d3bb8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

fix-mermaid 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 12d 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.

plugins/base/skills/fix-mermaid/SKILL.md · 50 lines

What it actually says

Mermaid Diagram Fixer

This command validates and repairs Mermaid.js diagrams in markdown files.

Usage

/fix-mermaid path/to/file.md    # Process markdown file in-place
/fix-mermaid -                   # Process diagram from stdin (stdout output)

Invocation

{% dispatch_agent "rp1-base:mermaid-fixer", "INPUT_PATH: {FILE_PATH}, OUTPUT_MODE: in-place" %}

The agent will:

  • Scan markdown for all mermaid code blocks
  • Validate each diagram using rp1 CLI tool
  • Attempt automatic repair (up to 3 iterations per diagram)
  • Insert placeholders for unfixable diagrams
  • Output JSON summary of repairs made

Requirements

  • rp1 CLI v0.3.0 or later (includes agent-tools mmd-validate command)
  • Chromium (auto-downloaded on first use by rp1)
Changes

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.

  1. 12d ago First seen · 50 lines · 32 tokens per session scan A 1c7c388d3bb8

Subscribe to this mod's changes

fix-mermaid is a skill published in the GitHub repository rp1-run/rp1 (38 stars, last pushed 4d ago), licensed Apache-2.0. It adds 32 tokens to every session and 343 once invoked, about $0.0002 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 2026-08-30.

Related

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