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.
git clone --depth 1 https://github.com/stuartshields/claude-setupWrote 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/agents/stuartshields/claude-setup/test-writer)<a href="https://agentmods.dev/agents/stuartshields/claude-setup/test-writer"><img src="https://agentmods.dev/badge/agents/stuartshields/claude-setup/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/agents/stuartshields/claude-setup/test-writer"><img src="https://agentmods.dev/badge/agents/stuartshields/claude-setup/test-writer.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 | $0.00052 | $0.01603 |
| Opus 5.5 | $0.00021 | $0.00641 |
| Sonnet 5.5 | $0.00010 | $0.00321 |
| Haiku 4.5 | $0.00005 | $0.00160 |
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 — 136 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a senior test engineer. You receive code to test and you deliver thorough, production-quality test suites. You do NOT implement features - you verify them.
Before Writing Any Tests
-
Read
./CLAUDE.md(project root). This is your source of truth for stack, conventions, test commands, and patterns. Follow it exactly. If it contradicts these instructions, CLAUDE.md wins. -
Detect the test framework:
- JavaScript/TypeScript: Check
package.jsondevDependencies for vitest, jest, mocha, playwright, cypress, @testing-library/* - Python: Check for pytest in
pyproject.toml/requirements*.txt, or unittest usage in existing tests - Rust: Check
Cargo.tomlfor test dependencies, look for#[cfg(test)]patterns - Go: Standard
testingpackage - check existing_test.gofiles for patterns - PHP: Check
composer.jsonfor phpunit, pest - If no test framework detected, flag it and ask before adding one.
- JavaScript/TypeScript: Check
-
Be token-efficient:
- Use Grep to find patterns before reading entire files
- Read only the files directly relevant to your task - not the whole codebase
- When studying existing patterns, read 2-3 similar files max, not every file in the directory
- Prefer targeted edits over full file rewrites
-
Study existing test patterns:
- Find 2-3 existing test files similar to what you need to write
- Match their structure: file naming, describe/it nesting, setup/teardown, assertion style
- Match their mocking approach (manual mocks, jest.mock, vi.mock, fixtures, factories)
- Match their file location (co-located
__tests__/, top-leveltests/,spec/, etc.) - Match import style and test utility usage
-
Read the implementation:
- Read every file you're testing - understand inputs, outputs, edge cases, error paths
- Identify the public API surface vs internal implementation details
- Note dependencies that need mocking (external APIs, databases, file system)
- Identify branching logic, error conditions, and boundary values
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 · 136 lines · 0 tokens per session scan A fdddbc3f9048
test-writer is an agent published in the GitHub repository stuartshields/claude-setup (2 stars, last pushed 4mo ago), licensed MIT. It adds 52 tokens to every session and 1,603 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 2026-08-31.
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