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.
git clone --depth 1 https://github.com/ohah/react-native-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/rules/ohah/react-native-mcp/mcp-tool-descriptions)<a href="https://agentmods.dev/rules/ohah/react-native-mcp/mcp-tool-descriptions"><img src="https://agentmods.dev/badge/rules/ohah/react-native-mcp/mcp-tool-descriptions/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/rules/ohah/react-native-mcp/mcp-tool-descriptions"><img src="https://agentmods.dev/badge/rules/ohah/react-native-mcp/mcp-tool-descriptions.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 | $0.00263 | $0.00263 |
| Opus 5.5 | $0.00105 | $0.00105 |
| Sonnet 5.5 | $0.00053 | $0.00053 |
| Haiku 4.5 | $0.00026 | $0.00026 |
Grade A, and why
mcp-tool-descriptions 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 1mo 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
MCP 도구 description 규칙
MCP 서버에 등록하는 도구의 description과 스키마 파라미터 describe()는 모두 영어로 작성한다.
registerTool(..., { description: '...' })의 description 문자열 → 영어- zod 스키마의
.describe('...')(사용자에게 노출되는 파라미터 설명) → 영어
코드 주석(JSDoc, 인라인)은 프로젝트 코딩 스타일대로 한글 가능. 사용자/클라이언트에 노출되는 도구 설명만 영어.
길이 권장 (초기 컨텍스트/토큰 절감)
- 도구
description: 1문장, 80~100자 권장. 워크플로·상세는 문서로 분리. - 파라미터
.describe(): 한 줄 한 문구. 상세 문법·옵션은 "See docs/..." 로 대체. - 너무 짧으면 AI가 사용 시점을 놓치고, 너무 길면 tools/list 토큰이 커짐. 핵심만 노출.
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.
- 1mo ago First seen · 20 lines · 263 tokens per session scan A 58d061425d82
mcp-tool-descriptions is a cursor rule published in the GitHub repository ohah/react-native-mcp (7 stars, last pushed 7mo ago), licensed MIT. It adds 263 tokens to every session, about $0.0011 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 2026-08-31.
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