Borrowing it
Nothing to install: this file belongs to gabrielg2020/govuk-frontend-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/gabrielg2020/govuk-frontend-mcp/main/CLAUDE.mdgit clone --depth 1 https://github.com/gabrielg2020/govuk-frontend-mcpWrote 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/instructions/gabrielg2020/govuk-frontend-mcp/claude-md)<a href="https://agentmods.dev/instructions/gabrielg2020/govuk-frontend-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/gabrielg2020/govuk-frontend-mcp/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.
<a href="https://agentmods.dev/instructions/gabrielg2020/govuk-frontend-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/gabrielg2020/govuk-frontend-mcp/claude-md.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 | $0.00924 | $0.00924 |
| Opus 5 | $0.00462 | $0.00462 |
| Sonnet 5 | $0.00185 | $0.00185 |
| Haiku 4.5 | $0.00092 | $0.00092 |
Grade A, and why
govuk-frontend-mcp 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 11d 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 — 115 lines — stays where its author put it; the contents beside it link to each section on GitHub.
govuk-frontend-mcp
MCP server exposing GOV.UK Frontend components, Design System patterns and styles as resources.
Structure
src/
├── index.ts # Server - registers resources
├── resources/ # Resource handlers
├── utils/tool-helpers.ts # Shared utilities
├── data/components.json # Generated data (don't edit)
├── data/patterns.json # Generated data (don't edit)
└── data/styles.json # Generated data (don't edit)
scripts/build-data.ts # Extracts data from govuk-frontend package
scripts/build-patterns.ts # Fetches pattern data from GitHub (alphagov/govuk-design-system, v5 branch)
scripts/build-styles.ts # Fetches style data from GitHub (alphagov/govuk-design-system, v5 branch)
Commands
npm run clean # Remove the dist/ directory
npm run build:data -- <version> # Extract component data from node_modules (optionally install govuk-frontend@<version> first, unsaved)
npm run build:patterns -- <branch> # Fetch pattern data from GitHub (defaults to v5)
npm run build:styles -- <branch> # Fetch style data from GitHub (defaults to v5)
npm run build # clean + build:data + build:patterns + build:styles + compile TypeScript
npm run typecheck # Type-check src/ and scripts/ without emitting
npm run dev # Run in development
Note: the -- separator before the branch argument is required — without it, npm swallows the argument and it never reaches the script.
Available Resources
govuk://components- List all available componentsgovuk://component/{name}- Get specific component detailsgovuk://patterns- List all available Design System patternsgovuk://pattern/{name}- Get specific pattern guidancegovuk://styles- List all available Design System stylesgovuk://style/{name}- Get specific style guidance (govuk://style/page-templateincludes the annotated Nunjucks template)govuk://version- Version metadata for the server, components package and design-system branches
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.
- 11d ago First seen · 115 lines · 924 tokens per session scan A 5ab9bcb92808
govuk-frontend-mcp CLAUDE.md is an instructions file published in the GitHub repository gabrielg2020/govuk-frontend-mcp (0 stars, last pushed 5mo ago), licensed MIT. It adds 924 tokens to every session, about $0.0046 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 2026-08-31.
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