Code Review & Testing · IN-DEPTH PROFILE

tdd Skill

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 2026-09-23

Pinned revision · c55ee460

Open pinned commit ↗
SkillSignal profileSource-grounded

Updated 2026-08-20

Runtime & securityNot independently verified

Source review does not certify behavior or safety.

IN PLAIN ENGLISH

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.

This is aimed at Engineers implementing behavior incrementally. Compare the examples below with your task, then review the limitations, permissions, and risks before installing.

What you get
  • Agree test seamsIdentify public boundaries before writing tests.
  • Run vertical cyclesWrite one failing behavior test, implement it, then repeat.
  • Refactor on greenImprove structure only after the behavior suite passes.
What makes it different
  • This profile is manually organized around the current upstream SKILL.md workflow.
  • The capability boundary remains explicitly tied to mattpocock.
  • Core uses, limitations, and risks are separated for pre-install review.
Community signalskills.sh All-time: #5 · 970.9K installs

No verified review text is in the current dataset. Use the linked source for the latest discussion.

Read the source note ↗

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 install (recommended)
npx skills add https://github.com/mattpocock/skills --skill tdd --agent claude-code
Personal install
npx skills add https://github.com/mattpocock/skills --skill tdd --agent claude-code -g

Project install stays with this repository for team sharing. Personal install adds -g and works across repositories.

View install paths
Project path.claude/skills/tdd/
Personal path~/.claude/skills/tdd/
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.

COMPARE THE TRADEOFF

Consider these close alternatives

These are deterministic nearby candidates, not paid placements or a universal ranking. Open the full profile before choosing.

01

Same job family · native to Claude Code + Codex

frontend-design

Design constraints that push generated interfaces beyond generic AI UI.
Tradeoff to check
Aesthetic judgments remain subjective and still need stakeholder review.
First risk
Style over function · Medium
Source state
Pinned · 34040c9c
Open frontend-design profile ↗
02

Same job family · native to Codex + Claude Code

web-design-guidelines

Review interfaces against practical web design and accessibility rules.
Tradeoff to check
It depends on network access and a live guideline document whose contents can change over time.
First risk
Rule drift or context-free findings · Medium
Source state
Pinned · 063bee94
Open web-design-guidelines profile ↗
03

Same job family · native to Codex + Claude Code

anti-ui-slop

Instruction-only, product-specific UI design contracts with optional real-interface evidence and a hard finish gate.
Tradeoff to check
Repository evidence is required; UIZZE references or user-provided screenshots are optional, and missing reference evidence should be labeled rather than guessed.
First risk
Copying external interface patterns too literally · Medium
Source state
Pinned · 1f564408
Open anti-ui-slop profile ↗
Compare more in the directory →

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.

COMMON QUESTIONS

tdd Skill FAQ

What is the tdd Skill?

A practical test-driven development workflow for coding agents. 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.

How do I install the tdd Skill?

Open and review the listed source, choose the project or personal path for your Agent, then verify the first run in a controlled project. Open the listed skills.sh page and upstream repository; verify the current SKILL.md.

Is the tdd Skill safe to use?

SkillSignal checked the source on 2026-09-23, but that is not a runtime test or security certification. Review the “False confidence” risk first and begin with the least access required.

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.