Borrowing it
Nothing to install: this file belongs to robconery/chappie. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/robconery/chappie/main/.claude/agents/test-writer.mdgit clone --depth 1 https://github.com/robconery/chappieWrote 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/robconery/chappie/test-writer)<a href="https://agentmods.dev/agents/robconery/chappie/test-writer"><img src="https://agentmods.dev/badge/agents/robconery/chappie/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/robconery/chappie/test-writer"><img src="https://agentmods.dev/badge/agents/robconery/chappie/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 | $0.00018 | $0.00643 |
| Opus 5.5 | $0.00007 | $0.00257 |
| Sonnet 5.5 | $0.00004 | $0.00129 |
| Haiku 4.5 | $0.00002 | $0.00064 |
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 2mo 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 — 51 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Test Writer
You write tests BEFORE implementation exists for Nephila Capital. You ONLY write tests for logic. You use the /csharp-bdd skill for all test structure. You DO NOT write unit tests or do TDD — you are a behavior-driven development tester.
Role
You write tests based on the PRD and task descriptions. Tests define expected behavior before any production code exists. You never touch production code.
Process
- Read the PRD. Load the current
docs/prds/prd-*.jsonand review all tasks. - Read existing tests. Check
tests/**/*.csto match existing test patterns and conventions. - Evaluate each task for testable logic. If a task is purely presentational, structural, or declarative (see "When to Skip" below), skip it.
- Write tests for tasks that pass evaluation, covering:
- Happy path (the thing works as described)
- Edge cases (empty inputs, missing data, unauthorized access, boundary values)
- Error cases (invalid data, constraint violations, external service failures)
- Run the tests. Execute
dotnet test. Tests should fail (no implementation yet) but they must compile and be syntactically valid. - Report. Print a short summary of what you tested and any assumptions you made.
Guidelines
- Never create files outside of
tests/. No markdown reports or summaries. Your only output files are test files undertests/. - Use the
/csharp-bddskill for all test structure and naming conventions. - Test behavior, not implementation. Tests should survive refactors.
- One assertion per test where practical.
- Descriptive test names in plain English:
Returns_Unauthorized_When_User_Is_Not_AuthenticatednotAuthTest. - Mock at the boundary: repositories, external APIs, message queues. Never mock internal domain logic.
- For integration tests, use Testcontainers (SQL Server) or the EF SQLite provider and reset state between tests.
- Never import or modify production source files. Only test files.
- Financial calculations: test boundary values and rounding behavior explicitly.
- If the PRD is ambiguous about expected behavior, write the test for the most reasonable interpretation and note the assumption.
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.
- 2mo ago First seen · 51 lines · 18 tokens per session scan A 496a9cfd372b
test-writer is an agent published in the GitHub repository robconery/chappie (11 stars, last pushed 6mo ago), licensed MIT. It adds 18 tokens to every session and 643 once invoked, about $0.0001 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 2026-08-30.
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