What is skills CLAUDE.md?

A set of instructions for an open-source collection of reusable skills and plugins, including tools for open data, charts, and SVG design. A plugin is a package that groups related agent capabilities.

Use it to add a new skill, organize plugin files, define plugin metadata, register plugins in the marketplace, or work with the open-data, chart, and design examples.

It explains the required folders, metadata files, namespaces, and marketplace registration needed to add or install skills consistently.

How tryopendata/skills configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to tryopendata/skills. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/tryopendata/skills/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/tryopendata/skills

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/tryopendata/skills/claude-md/github.svg)](https://agentmods.dev/instructions/tryopendata/skills/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/tryopendata/skills/claude-md"><img src="https://agentmods.dev/badge/instructions/tryopendata/skills/claude-md/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/tryopendata/skills/claude-md"><img src="https://agentmods.dev/badge/instructions/tryopendata/skills/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,192 This file is loaded in full into every session.

When invoked 1,192 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.01192	$0.01192
Opus 5.5	$0.00477	$0.00477
Sonnet 5.5	$0.00238	$0.00238
Haiku 4.5	$0.00119	$0.00119

Measured 2mo ago against content hash 450fcf90654c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

skills CLAUDE.md 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 2mo 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.

CLAUDE.md · 145 lines

How it starts

The opening of the file, as written. The whole thing — 145 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OpenData Skills

Cross-platform agent skills repo following the Agent Skills specification.

Repo: https://github.com/tryopendata/skills
Spec: https://agentskills.io

Plugins

This repo contains multiple independently installable plugins:

Plugin	Namespace	Source	Skills
opendata	`opendata`	`plugins/opendata/`	`opendata-api`
openchart	`openchart`	`plugins/openchart/`	`openchart`
opendesign	`opendesign`	`plugins/opendesign/`	`svg-design`

Each plugin has its own plugins/<name>/.claude-plugin/plugin.json for metadata. The root .claude-plugin/marketplace.json registers all plugins.

Directory Structure

.claude-plugin/
  marketplace.json         # root marketplace registry (all plugins)
plugins/
  opendata/
    .claude-plugin/plugin.json
    skills/
      opendata-api/
    commands/              # when needed
    agents/                # when needed
  openchart/
    .claude-plugin/plugin.json
    skills/
      openchart/
  opendesign/
    .claude-plugin/plugin.json
    skills/
      svg-design/

Adding a Skill

Create plugins/<plugin>/skills/<name>/SKILL.md with YAML frontmatter:

---
name: my-skill-name
description: >
  What this skill does and when to use it. Use imperative phrasing
  like "Use when..." Max 1024 chars.
---

name field: lowercase letters, numbers, hyphens only. Max 64 chars. Must match the parent directory name. No leading/trailing/consecutive hyphens.
description field: Describe what and when. Use imperative phrasing ("Use when..."). Focus on user intent, not implementation. Max 1024 chars.
Optional frontmatter: license, compatibility, metadata (key-value map), allowed-tools (space-delimited)
Body: Instructions for the agent. Keep under 500 lines / 5000 tokens. Split large content into references/ files and reference them conditionally ("Read references/api-errors.md if the API returns a non-200 status").

Read the full file on GitHub · 145 lines

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.

2mo ago First seen · 145 lines · 1,192 tokens per session scan A 450fcf90654c

Subscribe to this mod's changes

skills CLAUDE.md is an instructions file published in the GitHub repository tryopendata/skills (153 stars, last pushed 3mo ago), licensed MIT. It adds 1,192 tokens to every session, about $0.0048 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.

skills CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
skills CLAUDE.mdtryopendata/skills	Instructions file	153	3mo ago	MIT	A	1,192	Claude Code
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

skills: Instructions file for Claude Code