/tdd

A command that applies test-driven development, or TDD: write a failing test, implement the smallest change that passes it, then improve the code while keeping tests passing.

In plain words
What is it for?
Use it to define interfaces, create tests first, implement features or fixes, run the test cycle, refactor safely, and check that test coverage reaches the stated 80% target.
Why use it?
It makes the expected behaviour explicit before implementation and helps catch regressions during feature work, bug fixes, and refactoring.

Command

Part of the claude-code-mastery plugin — 1 skill, 12 commands, 3 agents shipped together

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 commands/mckruz/claude-code-mastery/tdd
Clone the repo
git clone --depth 1 https://github.com/MCKRUZ/claude-code-mastery

Or install claude-code-mastery, the plugin that ships this one along with the rest of its 1 skill, 12 commands, 3 agents.

Per session 31 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 720 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 $0.00031 $0.00720
Opus 5 $0.00015 $0.00360
Sonnet 5 $0.00006 $0.00144
Haiku 4.5 $0.00003 $0.00072

Measured 3d ago against content hash df6c33e76276, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

/tdd 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.

cursor-export/commands/tdd.md · 111 lines

How it starts

The opening of the file, as written. The whole thing — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.

TDD Command

Enforce test-driven development methodology for the requested feature or fix.

Workflow

  1. Scaffold Interfaces - Define types/interfaces first
  2. Generate Tests First - Write failing tests (RED)
  3. Implement Minimal Code - Write just enough to pass (GREEN)
  4. Refactor - Improve code while keeping tests green (REFACTOR)
  5. Verify Coverage - Ensure 80%+ test coverage

When to Use

Use /tdd when:

  • Implementing new features
  • Adding new functions/components
  • Fixing bugs (write test that reproduces bug first)
  • Refactoring existing code
  • Building critical business logic

TDD Cycle

RED -> GREEN -> REFACTOR -> REPEAT

RED:      Write a failing test
GREEN:    Write minimal code to pass
REFACTOR: Improve code, keep tests passing
REPEAT:   Next feature/scenario

Process

  1. Define interfaces for inputs/outputs
  2. Write tests that will FAIL (because code doesn't exist yet)
  3. Run tests and verify they fail for the right reason
  4. Write minimal implementation to make tests pass
  5. Run tests and verify they pass
  6. Refactor code while keeping tests green
  7. Check coverage and add more tests if below 80%

TDD Best Practices

DO:

  • Write the test FIRST, before any implementation
  • Run tests and verify they FAIL before implementing
  • Write minimal code to make tests pass
  • Refactor only after tests are green
  • Add edge cases and error scenarios
  • Aim for 80%+ coverage (100% for critical code)

DON'T:

  • Write implementation before tests
  • Skip running tests after each change
  • Write too much code at once
  • Ignore failing tests
  • Test implementation details (test behavior)
  • Mock everything (prefer integration tests)

Test Types to Include

Unit Tests (Function-level):

  • Happy path scenarios
  • Edge cases (empty, null, max values)
  • Error conditions
  • Boundary values

Integration Tests (Component-level):

  • API endpoints
  • Database operations
  • External service calls
  • Components with hooks/services

Read the full file on GitHub · 111 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. 3d ago First seen · 111 lines · 31 tokens per session scan A df6c33e76276

Subscribe to this mod's changes

/tdd is a command published in the GitHub repository MCKRUZ/claude-code-mastery (11 stars, last pushed 4mo ago), licensed MIT. It adds 31 tokens to every session and 720 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 2026-08-30.