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 Ozzeron/prompt-pack --skill test-writergit clone --depth 1 https://github.com/Ozzeron/prompt-packWrote 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/ozzeron/prompt-pack/test-writer)<a href="https://agentmods.dev/skills/ozzeron/prompt-pack/test-writer"><img src="https://agentmods.dev/badge/skills/ozzeron/prompt-pack/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/ozzeron/prompt-pack/test-writer"><img src="https://agentmods.dev/badge/skills/ozzeron/prompt-pack/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 | $0.00095 | $0.02435 |
| Opus 5.5 | $0.00038 | $0.00974 |
| Sonnet 5.5 | $0.00019 | $0.00487 |
| Haiku 4.5 | $0.00010 | $0.00244 |
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.
How it starts
The opening of the file, as written. The whole thing — 241 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Test Writer
You write tests for existing code. Tests document behaviour and catch regressions; they are not a coverage-percentage box to tick. You test what the code is supposed to do, not how it's currently structured. Implementation-coupled tests rot the moment refactors happen and become a tax on every change.
When to use
- Adding tests to existing untested code
- Filling a coverage gap on a specific function / component / endpoint
- Writing tests that should have caught a bug just fixed (regression tests)
- Pre-launch test pass for a feature
Do not invoke for:
- Writing code with tests included — that's part of
architecture/frontend-feature,architecture/backend-api, or whichever skill is doing the work - E2E test infrastructure setup — flag as separate work
- Snapshot-only changes (regenerating snapshots without thinking is not testing)
Scope
In scope:
- Unit tests for pure logic (functions, hooks, utilities, components)
- Integration tests at module / API / data-layer boundary
- Regression tests for fixed bugs
- Test fixtures and factories
- Mocking at the right boundary
Out of scope:
- E2E / browser / Playwright / Cypress test infrastructure (delegate or flag)
- Performance / load / chaos tests
- Test framework selection — match what the project uses
Inherits
meta/engineering-principles— naming, file size, single responsibility apply to tests too.meta/reuse-before-create— before writing a new fixture, factory, mock, or test helper, search for an existing one in the test tree; tests duplicate setup more than any other code.meta/token-discipline— read the unit under test and 1–2 sibling tests for style; not the whole test suite.
Token discipline (specific)
- Read the unit under test and its direct dependencies. Don't recursively read the whole module graph.
- Read 1–2 existing tests in the same project to learn conventions:
- Test file location (colocated vs
__tests__/vs mirrored structure) - Naming style (
describe('X')vstest('does Y')) - Setup / teardown patterns
- Fixture / factory helpers in use
- Test file location (colocated vs
- Read the test framework config (
vitest.config.*,jest.config.*,pytest.ini, etc.) once, only if needed. - Do NOT read tests of unrelated features.
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 Changed · +2 lines · +69 tokens per session 8fa5c67ac9ef
- 1mo ago First seen · 239 lines · 26 tokens per session scan A c0b2727e1ac6
test-writer is a skill published in the GitHub repository Ozzeron/prompt-pack (8 stars, last pushed 1mo ago), licensed MIT. It adds 95 tokens to every session and 2,435 once invoked, about $0.0004 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 2026-08-31.
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