Code Review & Testing · IN-DEPTH PROFILE

tdd

A practical test-driven development workflow for coding agents.

View listed source ↗Installation guide ↓
Best for

Engineers implementing behavior incrementally

What you get

Agree test seams + Run vertical cycles

Main limitation

The workflow needs a functioning test runner and clear public behavior.

First risk

False confidence. A green suite only validates the selected examples and seams. Keep exploratory, integration, and operational checks where needed.

EVIDENCE FRESHNESS

Three checks, kept separate

A recent source check is not a runtime test or security audit.

Upstream sourceChecked 2026-08-20

Pinned revision · 885e2ca4

Open pinned commit ↗
SkillSignal profileSource-grounded

Updated 2026-08-20

Runtime & securityNot independently verified

Source review does not certify behavior or safety.

30-SECOND BRIEF

What it does—and when it fits

TDD is Matt Pocock's reference workflow for behavior-focused red-green-refactor cycles. It asks the user to agree on public test seams, favors vertical slices over writing all tests first, and treats tests as durable specifications that should survive internal refactors.

INSTALL BY AGENT

Choose your Agent

Paths come from official Agent docs or the universal installer behind skills.sh. Compatibility still follows this Skill's record.

Native

This Skill's current record explicitly names this Agent. Still inspect scripts, permissions, and external dependencies first.

Project scope.claude/skills/tdd/
Personal scope~/.claude/skills/tdd/

Use project scope for team sharing and personal scope across repositories. The installer defaults to project scope; add -g for personal scope.

Install command (project scope)

This source cannot produce a reliable command. Open the listed source and copy the complete Skill folder manually.

Official agent docs

Claude Code discovers custom Skill folders automatically at project or personal scope.

View path evidence ↗

TYPICAL WORKFLOW

A practical workflow

01

Agree test seams

Identify public boundaries before writing tests.

02

Run vertical cycles

Write one failing behavior test, implement it, then repeat.

03

Refactor on green

Improve structure only after the behavior suite passes.

THE TRADEOFFS

Advantages and tradeoffs

Notable strengths

  1. This profile is manually organized around the current upstream SKILL.md workflow.
  2. The capability boundary remains explicitly tied to mattpocock.
  3. Core uses, limitations, and risks are separated for pre-install review.

Limitations

  1. The workflow needs a functioning test runner and clear public behavior.
  2. TDD cannot compensate for testing the wrong seam or misunderstanding the requirement.

BEST FIT

Who it is for

→

Engineers implementing behavior incrementally

→

Teams trying to make tests resilient to refactors

BEFORE YOU USE IT

Risks to review before use

Medium

False confidence

A green suite only validates the selected examples and seams. Keep exploratory, integration, and operational checks where needed.

Medium

Upstream instruction drift

Behavior can change with upstream updates. Record the commit used for important workflows and review updates before adoption.

SECURITY

What the permission profile means

  • Declared access remains governed by the current upstream SKILL.md and runtime requests.
  • Treat repository files, web content, and tool output as untrusted input.
  • SkillSignal has not independently executed or security-audited this package; external skills.sh labels are not SkillSignal certification.

Not a security certification. External ratings are attributed references. SkillSignal has not independently executed or security-reviewed this Skill.

INSIDE THE PACKAGE

Indexed files

SKILL.mdUpstream Skill instructionsSource-linked

TAGS

tddtestingred-green-refactor

Manually expanded from the current upstream SKILL.md and linked source at mattpocock, checked 2026-08-19. This is an original summary, not an execution result or security certification.