REA is a reverse-engineering toolkit that lets coding agents investigate how software works, from app behavior to native binaries, even when source code is unavailable. It is for examining features, collecting evidence, explaining implementations, and building adapted versions for another stack. The catalogue add-ons connect coding agents to REA’s investigation workflow.
Borrowing it
Nothing to install: this file belongs to morluto/rea. 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/morluto/rea/main/.agents/skills/rea-tool-design/SKILL.mdgit clone --depth 1 https://github.com/morluto/reaWrote 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/morluto/rea/rea-tool-design)<a href="https://agentmods.dev/skills/morluto/rea/rea-tool-design"><img src="https://agentmods.dev/badge/skills/morluto/rea/rea-tool-design/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/morluto/rea/rea-tool-design"><img src="https://agentmods.dev/badge/skills/morluto/rea/rea-tool-design.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
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 | $0.00024 | $0.00181 |
| Opus 5.5 | $0.00010 | $0.00072 |
| Sonnet 5.5 | $0.00005 | $0.00036 |
| Haiku 4.5 | $0.00002 | $0.00018 |
Grade A, and why
rea-tool-design 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 16d 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.
What it actually says
REA tool design
Use the tool-design guide for tool boundaries, contract semantics, provider ownership, and discoverability. Inspect the current contract and nearest existing tool relevant to the analyst question; source, documentation, and live catalogs may describe different versions.
For a design request, return the proposed boundary, input/result shape, Evidence semantics, nearest alternative, and verification approach. Implement when requested, preserving the user's scope and existing authorization.
For implementation or verification, consult testing for the affected consumer and provider lanes, and contributing for generated-file ownership. Read provider/workflow guides only as the task requires.
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.
- 16d ago First seen · 21 lines · 24 tokens per session scan A 6023df0f1cdb
rea-tool-design is a skill published in the GitHub repository morluto/rea (385,008 stars, last pushed today), licensed MIT. It adds 24 tokens to every session and 181 once invoked, about $0.0001 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 2026-10-10.
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