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 hamzafarooq/claude-code-starter --skill test-writergit clone --depth 1 https://github.com/hamzafarooq/claude-code-starterWrote 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/hamzafarooq/claude-code-starter/test-writer)<a href="https://agentmods.dev/skills/hamzafarooq/claude-code-starter/test-writer"><img src="https://agentmods.dev/badge/skills/hamzafarooq/claude-code-starter/test-writer/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/hamzafarooq/claude-code-starter/test-writer"><img src="https://agentmods.dev/badge/skills/hamzafarooq/claude-code-starter/test-writer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00041 | $0.00301 |
| Opus 5.5 | $0.00016 | $0.00120 |
| Sonnet 5.5 | $0.00008 | $0.00060 |
| Haiku 4.5 | $0.00004 | $0.00030 |
Grade A, and why
test-writer 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
Ask the user to share the function or code they want tests for.
Then write tests covering:
Tests for [functionName]
Testing framework: [detect from package.json — Jest, Vitest, pytest, etc. Ask if unclear]
Happy path
Test the expected behavior with valid inputs. One test per meaningful variation.
test('returns [expected] when given [input]', () => {
// arrange
// act
// assert
})
Edge cases
Tests for boundary conditions and unusual but valid inputs:
- Empty input (empty string, empty array, 0)
- Single item
- Maximum size or value
- Special characters (if string input)
Error cases
Tests that verify the function fails correctly:
- Invalid input types
- Null/undefined inputs
- Inputs that should trigger error handling
Mock requirements
List any external dependencies (API calls, database queries, file system) that need mocking, with example mock setup.
Coverage target: Aim for all branches, not just lines. Flag any branch that is difficult to test and explain why.
Write tests that read like documentation — the test name should be a sentence explaining what the function does in that scenario.
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 · 48 lines · 41 tokens per session scan A 34ad12153c8d
test-writer is a skill published in the GitHub repository hamzafarooq/claude-code-starter (145 stars, last pushed 7d ago), licensed MIT. It adds 41 tokens to every session and 301 once invoked, about $0.0002 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 2026-09-03.
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