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 skills/itechmeat/llm-code/react-testing-librarynpx skills add itechmeat/llm-code --skill react-testing-librarygit clone --depth 1 https://github.com/itechmeat/llm-codeWhat 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 | $0.00071 | $0.02348 |
| Opus 5 | $0.00036 | $0.01174 |
| Sonnet 5 | $0.00014 | $0.00470 |
| Haiku 4.5 | $0.00007 | $0.00235 |
Grade A, and why
react-testing-library 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 2d 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 — 411 lines — stays where its author put it; the contents beside it link to each section on GitHub.
React Testing Library Skill
Quick Navigation
| Topic | Link |
|---|---|
| Queries | references/queries.md |
| User Events | references/user-events.md |
| API | references/api.md |
| Async | references/async.md |
| Debugging | references/debugging.md |
| Config | references/config.md |
Installation
Install: npm install --save-dev @testing-library/react @testing-library/dom. Recommended extras: @testing-library/user-event and @testing-library/jest-dom. React 19 requires v16.1.0+.
Core Philosophy
"The more your tests resemble the way your software is used, the more confidence they can give you."
Avoid testing:
- Internal state of components
- Internal methods
- Lifecycle methods
- Child component implementation details
Test instead:
- What users see and interact with
- Behavior from user's perspective
- Accessibility (queries by role, label)
Query Priority
Use queries in this order of preference:
1. Accessible to Everyone (Preferred)
// Best — by ARIA role
getByRole("button", { name: /submit/i });
getByRole("textbox", { name: /email/i });
// Form fields — by label
getByLabelText("Email");
// Non-interactive content — by text
getByText("Welcome back!");
2. Semantic Queries
// Images
getByAltText("Company logo");
// Title attribute (less reliable)
getByTitle("Close");
3. Test IDs (Escape Hatch)
// Only when other queries don't work
getByTestId("custom-element");
Query Types
| Type | No Match | 1 Match | >1 Match | Async |
|---|---|---|---|---|
getBy... |
throw | return | throw | No |
queryBy... |
null | return | throw | No |
findBy... |
throw | return | throw | Yes |
getAllBy... |
throw | array | array | No |
queryAllBy... |
[] | array | array | No |
findAllBy... |
throw | array | array | Yes |
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 2d ago First seen · 411 lines · 71 tokens per session scan A 8049f7c21c30
react-testing-library is a skill published in the GitHub repository itechmeat/llm-code (22 stars, last pushed 1mo ago), licensed MIT. It adds 71 tokens to every session and 2,348 once invoked, about $0.0004 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.
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