work-test

A testing guide for inspecting a codebase and adding a small set of tests for behavior users or existing code rely on. TDD, or test-driven development, is a practice of writing tests before implementation; this add-on instead focuses on meaningful tests for existing behavior.

In plain words
What is it for?
It is for adding or improving unit, integration, or end-to-end tests after examining the implementation, existing tests, public interfaces, and real user flows.
Why use it?
It helps avoid tests that only increase coverage without checking something important, while following the repository’s current testing tools and conventions.

Skill for Claude CodeCodex

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 skills/xcaeser/work-skill/work-test
Any agent
npx skills add xcaeser/work-skill --skill work-test
Clone the repo
git clone --depth 1 https://github.com/xcaeser/work-skill

Made for: Claude Code, Codex.

Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 932 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 $0.00049 $0.00932
Opus 5 $0.00024 $0.00466
Sonnet 5 $0.00010 $0.00186
Haiku 4.5 $0.00005 $0.00093

Measured 2d ago against content hash d21fb54c937f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

work-test 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 2d 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.

skills/work-test/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Work / 4. Test

Write meaningful tests for behavior the product genuinely promises or currently depends on. The testing rules below are binding.

Work directly in the parent conversation. Do not spawn agents or register a goal unless the user explicitly asks. Testing is implementation work: inspect first, show the plan, make the smallest justified edits, run the tests, and report the evidence.

Inspect before writing

Read the applicable project instructions, repository status and diff, implementation, existing tests and helpers, public APIs, consumers, and actual user flows. Identify the behavior users or current callers rely on. Do not invent requirements, hypothetical threats, or unrealistic edge cases.

If the user did not name a target, choose the smallest coherent feature or current change that can be understood and tested safely. State the scope. If no meaningful behavior is worth testing, stop and explain why; never add a test only to increase coverage.

Publish the test plan

Before editing, provide one entry per justified behavior in this exact format:

  1. Behavior being protected
  2. Why it matters
  3. Test level: unit, integration, or end-to-end
  4. Exact observable assertion

Keep the plan short. Prefer a small number of high-value tests in this order:

  1. Core happy paths.
  2. Realistic failure paths.
  3. Important boundaries.
  4. Previously broken behavior.
  5. Data persistence, permissions, billing, authentication, or destructive actions when relevant.

Select meaningful tests

  • Test observable behavior, not internal implementation details.
  • Test negative behavior only when a real contract or regression needs protection.
  • Prefer integration tests for interactions between modules owned by the project.
  • Mock external boundaries only when necessary: network APIs, time, randomness, queues, email, payment providers, or databases.
  • Use realistic inputs and fixtures. Keep tests deterministic and independent of execution order.
  • Assert the actual result, persisted state, returned error, emitted event, or externally visible side effect.
  • Keep each test focused on one behavior without splitting a simple workflow into redundant cases.

Read the full file on GitHub · 84 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 2d ago First seen · 84 lines · 49 tokens per session scan A d21fb54c937f

Subscribe to this mod's changes

work-test is a skill published in the GitHub repository xcaeser/work-skill (2 stars, last pushed 21d ago), licensed MIT. It adds 49 tokens to every session and 932 once invoked, about $0.0002 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.

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