callstack/react-native-testing-library is a testing library for React Native components that simulates the React Native runtime and supports tests focused on user-visible behavior. React Native developers use it with Jest to write maintainable component tests. Catalogue add-ons provide agents, instructions, and a skill for working with the library.
Borrowing it
Nothing to install: this file belongs to callstack/react-native-testing-library. 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/callstack/react-native-testing-library/main/AGENTS.mdgit clone --depth 1 https://github.com/callstack/react-native-testing-libraryWrote 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/callstack/react-native-testing-library/agents-md)<a href="https://agentmods.dev/instructions/callstack/react-native-testing-library/agents-md"><img src="https://agentmods.dev/badge/instructions/callstack/react-native-testing-library/agents-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/callstack/react-native-testing-library/agents-md"><img src="https://agentmods.dev/badge/instructions/callstack/react-native-testing-library/agents-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 | $0.01049 | $0.01049 |
| Opus 5.5 | $0.00420 | $0.00420 |
| Sonnet 5.5 | $0.00210 | $0.00210 |
| Haiku 4.5 | $0.00105 | $0.00105 |
Grade A, and why
react-native-testing-library AGENTS.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 17d 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 — 63 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Code Assistant Context
@testing-library/react-native is a TypeScript/Jest library for testing React Native components with user-focused testing patterns.
[!IMPORTANT] Never run git commands that create commits, push, or modify the index/history. The human stages and commits. See Agent rules.
- Package manager:
yarn([email protected]) - Common commands:
yarn testyarn test:ciyarn typecheckyarn lintyarn format:checkyarn buildyarn validate
- Contributor guides (shared with human contributors, see also CONTRIBUTING.md):
- Architecture and API design
- Build, validation, and repo layout
- TypeScript and code style
- Testing conventions
- Native event propagation (bubbling vs direct)
- Native state for uncontrolled components
- Event dispatch (
fireEventvsuserEvent) - Accessibility model
- Async,
act, and timers - Example app regeneration
- Git, releases, and PR workflow
Reference sources
refs/ holds upstream sources as shallow git submodules. Search them to see how upstream implements something (event dispatch, renderer internals, query semantics) instead of guessing or fetching from the web.
refs/react-native/: facebook/react-native (core components inpackages/react-native/Libraries/)refs/react/: facebook/react (reconciler and RN renderer inpackages/). RNTL renders throughtest-renderer, not the deprecatedreact-test-rendererfound here.refs/dom-testing-library/: testing-library/dom-testing-library (queries,fireEvent,waitFor)refs/react-testing-library/: testing-library/react-testing-library (render,actintegration)refs/expensify-app/: Expensify/App, about 1,000 test files using this library (tests/ui/,tests/unit/,tests/perf-test/). Use it to see real-world API usage and judge the impact of changes. It is on RNTL v13 (see itspackage.json), so syntax differs from v14:renderandfireEventare sync there.
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.
- 17d ago Changed · +18 lines · +464 tokens per session 64ca0247e5fd
- 24d ago Changed · +21 lines · +297 tokens per session 92f742e4b445
- 2mo ago First seen · 24 lines · 288 tokens per session scan A fa04f7288182
react-native-testing-library AGENTS.md is an instructions file published in the GitHub repository callstack/react-native-testing-library (3,427 stars, last pushed 9d ago), licensed MIT. It adds 1,049 tokens to every session, about $0.0042 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 2026-08-30.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.