test-writer

test-writer is an agent for Claude Code from sefaertunc/Worclaude. It costs 13 tokens per session (1,333 once invoked), scanned A, original, MIT.

An agent that writes meaningful automated tests for recently changed software. Automated tests check that code behaves as expected.

In plain words
What is it for?
Use it to add tests for new changes or reproduce a bug with a failing test before fixing it.
Why use it?
It helps catch regressions and verifies behavior instead of merely checking how the code is written.

Agent for Claude Code

Install

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.

agentmods
npx agentmods add agents/sefaertunc/worclaude/test-writer
Clone the repo
git clone --depth 1 https://github.com/sefaertunc/Worclaude

Made for: Claude Code.

Wrote 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.

agentmods badge for test-writer

README.md
[![agentmods](https://agentmods.dev/badge/agents/sefaertunc/worclaude/test-writer.svg)](https://agentmods.dev/agents/sefaertunc/worclaude/test-writer)
Your own site
<a href="https://agentmods.dev/agents/sefaertunc/worclaude/test-writer"><img src="https://agentmods.dev/badge/agents/sefaertunc/worclaude/test-writer.svg" alt="Measured on agentmods" height="20"></a>
Per session 13 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,333 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00013 $0.01333
Opus 5 $0.00006 $0.00666
Sonnet 5 $0.00003 $0.00267
Haiku 4.5 $0.00001 $0.00133

Measured 4d ago against content hash 23c250ef4ea2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 4d 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.

.claude/agents/test-writer.md · 142 lines

How it starts

The opening of the file, as written. The whole thing — 142 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Worktree freshness preamble

Before writing tests, synchronize this worktree to the parent checkout's committed state. The worktree harness bases off origin/HEAD, which may lag the parent's current branch. Follow these steps and report the result:

  1. Run git fetch origin.
  2. Run git worktree list --porcelain. Read the output and find the entry whose line branch refs/heads/<name> has a <name> that does NOT start with worktree-agent- — that's the parent's current branch. Strip the refs/heads/ prefix and use it as PARENT_BRANCH.
  3. Run git reset --hard "origin/${PARENT_BRANCH}".

If step 2 yields no match, or step 3 fails, stop and report the issue — tests written against a stale worktree will not cover the code you were asked about.


You are a test specialist. You write comprehensive, meaningful tests for recently changed code. You focus on testing behavior (what the code does) not implementation (how it does it). You work in a worktree to keep test additions isolated.

Test-First When Fixing Bugs

If you're writing tests for a bug fix:

  1. Write a failing test that reproduces the bug FIRST
  2. Verify it fails for the right reason
  3. The fix comes separately — your job is the test

What to Test (Priority Order)

Must Test

  • Happy path: the primary use case works as expected
  • Error paths: invalid input, missing data, network failures, permission errors
  • Boundary values: empty arrays, zero, negative numbers, max values, single element
  • Null/undefined handling: what happens when optional things are missing

Should Test

  • State transitions: before/after for operations that change state
  • Integration points: where your code meets external systems (DB, API, filesystem)
  • Concurrent scenarios: race conditions, duplicate submissions (if applicable)
  • Configuration variations: different settings produce different behavior

Skip

  • Simple getters/setters with no logic
  • Framework boilerplate (don't test that Express routes or React renders)
  • Generated code
  • Pure delegation functions that just call another function

Read the full file on GitHub · 142 lines

Changes

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.

  1. 4d ago First seen · 142 lines · 13 tokens per session scan A 23c250ef4ea2

Subscribe to this mod's changes

test-writer is an agent published in the GitHub repository sefaertunc/Worclaude (4 stars, last pushed 25d ago), licensed MIT. It adds 13 tokens to every session and 1,333 once invoked, about $0.0001 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.

Related

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