no-mcp-in-demo-app

no-mcp-in-demo-app is a cursor rule for Cursor from ohah/react-native-mcp. It costs 225 tokens per session, scanned A, original, MIT.

A rule that forbids adding MCP-specific code or changing the app, Babel, or MCP setup during demo and test testing.

In plain words
What is it for?
Use it when testing React Native MCP features, including clicks, labels, scrolling, and other actions, without modifying the demo or user app.
Why use it?
It keeps test results representative of the existing application instead of making the app pass by adding special support for the test tools.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/.

Good fit Use it when testing React Native MCP features, including clicks, labels, scrolling, and other actions, without modifying the demo or user app.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/ohah/react-native-mcp/no-mcp-in-demo-app
Install

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.

Clone the repo
git clone --depth 1 https://github.com/ohah/react-native-mcp

Made for: Cursor.

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.

agentmods badge for no-mcp-in-demo-app

README.md
[![agentmods](https://agentmods.dev/badge/rules/ohah/react-native-mcp/no-mcp-in-demo-app/github.svg)](https://agentmods.dev/rules/ohah/react-native-mcp/no-mcp-in-demo-app)
Your own site
<a href="https://agentmods.dev/rules/ohah/react-native-mcp/no-mcp-in-demo-app"><img src="https://agentmods.dev/badge/rules/ohah/react-native-mcp/no-mcp-in-demo-app/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.

agentmods 80×15 button for no-mcp-in-demo-app

Your own site · 80×15
<a href="https://agentmods.dev/rules/ohah/react-native-mcp/no-mcp-in-demo-app"><img src="https://agentmods.dev/badge/rules/ohah/react-native-mcp/no-mcp-in-demo-app.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 225 This file is loaded in full into every session.
When invoked 225 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00225 $0.00225
Opus 5 $0.00112 $0.00112
Sonnet 5 $0.00045 $0.00045
Haiku 4.5 $0.00022 $0.00022

Measured 8d ago against content hash c2e9dd329d5d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

no-mcp-in-demo-app 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 8d 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.

.cursor/rules/no-mcp-in-demo-app.mdc · 21 lines

What it actually says

MCP 테스트 시 수정 금지 (절대 규칙)

목적: 테스트/데모 앱이 MCP로 “잘 동작하게” 만들기 위해, 아래 셋을 수정하지 않는다.

사용자 앱 — 데모/테스트 앱·사용자 앱 소스 수정 금지

앱 소스 추가 금지

  • 테스트/데모 앱에 __REACT_NATIVE_MCP__ 참조 또는 호출 넣기 금지
  • MCP에 맞추기 위해 앱에 넣는 전용 로직 금지

AI 동작

  • “click(uid) 되게 해줘”, “동적 testID 지원해줘” 등 요청이 있어도, Babel·MCP·앱 중 어느 것도 수정하지 않는다.
  • 이미 있는 도구(click, click_by_label, scroll 등)로만 테스트하고, 한계는 그대로 둔다.
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.

  1. 8d ago First seen · 21 lines · 225 tokens per session scan A c2e9dd329d5d

Subscribe to this mod's changes

no-mcp-in-demo-app is a cursor rule published in the GitHub repository ohah/react-native-mcp (7 stars, last pushed 5mo ago), licensed MIT. It adds 225 tokens to every session, about $0.0011 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.