test-driven-development

A software development method called test-driven development, or TDD, where tests are written before the code and changes follow a Red, Green, Refactor cycle.

In plain words
What is it for?
Use it when adding core logic, fixing bugs, or turning requirements into small input-and-output tests.
Why use it?
It makes expected behavior explicit and helps prevent bugs from returning after code changes.

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/kbwen/agent-virtual-office/test-driven-development
Any agent
npx skills add KbWen/agent-virtual-office --skill test-driven-development
Clone the repo
git clone --depth 1 https://github.com/KbWen/agent-virtual-office

Made for: Claude Code, Codex.

Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 207 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod 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 $0.00023 $0.00207
Opus 5 $0.00012 $0.00103
Sonnet 5 $0.00005 $0.00041
Haiku 4.5 $0.00002 $0.00021

Measured 3d ago against content hash 762ab7b7099c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

test-driven-development 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 3d 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.

Origin

This is a copy

100% identical to test-driven-development — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/test-driven-development/SKILL.md · 30 lines

What it actually says

Test-Driven Development

Overview

TDD uses the Red → Green → Refactor micro-cycle. First, define expected behavior. Next, use a minimal implementation to pass the test. Finally, organize the code structure.

When to Use

  • Adding or modifying core logic.
  • Fixing bugs and needing regression protection.
  • Requirements can be written as explicit input/output acceptance tests.

Workflow

  1. Red: Write a failing test describing the expected behavior.
  2. Green: Write the minimal code to make the test pass.
  3. Refactor: Clean up naming, structure, and duplication.
  4. Repeat the cycle until acceptance criteria are met.

Ironclad Rules

  • Do NOT write massive amounts of features before writing tests.
  • Focus on one small goal per cycle.
  • All tests MUST pass after refactoring.
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. 3d ago First seen · 30 lines · 23 tokens per session scan A 762ab7b7099c

Subscribe to this mod's changes

test-driven-development is a skill published in the GitHub repository KbWen/agent-virtual-office (11 stars, last pushed 7d ago), licensed MIT. It adds 23 tokens to every session and 207 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to test-driven-development, differing in 0 lines, and is treated as a copy.

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