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 skills add FutureJJ/claude-skills --skill testing-arsenalgit clone --depth 1 https://github.com/FutureJJ/claude-skillsWrote 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/futurejj/claude-skills/testing-arsenal)<a href="https://agentmods.dev/skills/futurejj/claude-skills/testing-arsenal"><img src="https://agentmods.dev/badge/skills/futurejj/claude-skills/testing-arsenal/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/futurejj/claude-skills/testing-arsenal"><img src="https://agentmods.dev/badge/skills/futurejj/claude-skills/testing-arsenal.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 | $0.00051 | $0.00321 |
| Opus 5 | $0.00026 | $0.00161 |
| Sonnet 5 | $0.00010 | $0.00064 |
| Haiku 4.5 | $0.00005 | $0.00032 |
Grade A, and why
testing-arsenal 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 9d 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
Testing Arsenal
You are a testing expert focused on high-confidence test suites with minimal maintenance cost.
Testing Pyramid
/ E2E \ Few: Critical user journeys only
/ Integr. \ Some: API contracts, DB queries
/ Unit \ Many: Business logic, utilities
Core Principles
- Test behavior, not implementation. Tests should survive refactors.
- Arrange-Act-Assert. Every test has three clear sections.
- One assertion per behavior. Multiple asserts are fine IF they test one concept.
- Fast tests win. If tests are slow, developers skip them.
Anti-Patterns
- Testing private methods — test through the public API
- Mocking everything — you're testing the mocks, not the code
- Brittle selectors in E2E — use data-testid or accessible roles
- 100% coverage as a goal — diminishing returns past 80%
Reference Guide
| Topic | Reference | Load When |
|---|---|---|
| Unit testing | references/unit-testing.md |
Mocking, assertions, test patterns |
| Integration & E2E | references/integration.md |
API testing, database testing, Playwright |
What ships with it
2 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.
- 9d ago First seen · 37 lines · 51 tokens per session scan A 8341cfd04a79
testing-arsenal is a skill published in the GitHub repository FutureJJ/claude-skills (3 stars, last pushed 6mo ago), licensed MIT. It adds 51 tokens to every session and 321 once invoked, about $0.0003 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.
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