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 agentmods add instructions/reactjs/react.dev/claude-mdgit clone --depth 1 https://github.com/reactjs/react.devWhat 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 | $0.00393 | $0.00393 |
| Opus 5 | $0.00197 | $0.00197 |
| Sonnet 5 | $0.00079 | $0.00079 |
| Haiku 4.5 | $0.00039 | $0.00039 |
Grade A, and why
react.dev 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 yesterday.
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
Licensed CC-BY-4.0
The repository is licensed CC-BY-4.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.
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.
- yesterday First seen · 53 lines · 393 tokens per session scan A f4293082ecf6
react.dev CLAUDE.md is an instructions file published in the GitHub repository reactjs/react.dev (11,794 stars, last pushed 7d ago), licensed CC-BY-4.0. It adds 393 tokens to every session, about $0.0020 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.
Other instructions, from other repositories
react CLAUDE.md
Instructions for react/react, covering react, monorepo overview and current active work.
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Instructions for wasp-lang/wasp, covering wasp monorepo, repository structure, build & development, code conventions and haskell.
personal-site AGENTS.md
Instructions for mldangelo/personal-site, covering agents.md, quick commands, project structure, code style and git workflow.
react-horizontal-scrolling-menu AGENTS.md
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lingo.dev CLAUDE.md
Instructions for lingodotdev/lingo.dev, covering extremely important instructions for claude, fyi, tools, testing and changesets.
remotion copilot-instructions.md
Copilot instructions for remotion-dev/remotion, covering monorepo setup, build instructions, documentation and commit messages.