tdd-workflow

A tests-first workflow for building software: write a test that fails, add code to make it pass, then improve the code. It covers unit tests for individual parts, integration tests for connected parts, and end-to-end tests for complete user flows.

In plain words
What is it for?
Use it when developing a new feature, adding an API endpoint or user-facing component, or when a project requires tests before implementation.
Why use it?
It helps prevent new code from breaking existing behavior and makes missing edge cases and error handling easier to find. It also gives feature work a clear testing sequence when coverage is required.

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/cloudnative-co/claude-code-starter-kit/tdd-workflow
Any agent
npx skills add cloudnative-co/claude-code-starter-kit --skill tdd-workflow
Clone the repo
git clone --depth 1 https://github.com/cloudnative-co/claude-code-starter-kit

Made for: Claude Code, Codex.

Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 945 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 $0.00054 $0.00945
Opus 5 $0.00027 $0.00473
Sonnet 5 $0.00011 $0.00189
Haiku 4.5 $0.00005 $0.00094

Measured 2d ago against content hash c9578121f8c0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

tdd-workflow 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/check-coverage.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/tdd-workflow/SKILL.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Test-Driven Development Workflow

This skill provides a structured TDD workflow for projects that adopt tests-first development.

When to Activate

  • The user explicitly asks for TDD or tests-first development
  • New feature work where test coverage is a stated requirement
  • Adding API endpoints or components under a coverage policy

For routine bug fixes or refactors, add focused tests for the changed behavior instead of invoking this full workflow (the /tdd command and tdd-guide agent remain available when you want it explicitly).

Core Principles

1. Tests BEFORE Code

Within this workflow, the default is to write tests first, then implement code to make tests pass.

2. Coverage Guidance

  • Coverage target follows the project's own standard (e.g., 80% as a common baseline); scale effort with the size of the change
  • Cover relevant edge cases
  • Test error scenarios
  • Verify boundary conditions

3. Test Types

Unit Tests - Individual functions, utilities, component logic, pure functions, helpers.

Integration Tests - API endpoints, database operations, service interactions, external API calls.

E2E Tests (Playwright) - Critical user flows, complete workflows, browser automation, UI interactions. Applies to web UI projects only.

TDD Workflow Steps

Step 1: Write User Journeys

As a [role], I want to [action], so that [benefit]

Example:
As a user, I want to search for markets semantically,
so that I can find relevant markets even without exact keywords.

Step 2: Generate Test Cases

For each user journey, create comprehensive test cases covering happy paths, edge cases, fallback behavior, and sorting/filtering logic.

Step 3: Run Tests (They Should Fail)

Use the project's test runner. Examples:

npm test                      # Node.js
pytest                        # Python
bash tests/run-unit-tests.sh  # shell projects
# Tests should fail - we haven't implemented yet

Step 4: Implement Code

Write minimal code to make tests pass.

Read the full file on GitHub · 118 lines

Files

What ships with it

3 files 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 · 118 lines · 54 tokens per session scan A c9578121f8c0

Subscribe to this mod's changes

tdd-workflow is a skill published in the GitHub repository cloudnative-co/claude-code-starter-kit (147 stars, last pushed 9d ago), licensed MIT. It adds 54 tokens to every session and 945 once invoked, about $0.0003 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.

Related

Other skills, from other repositories

pest-testing

Use this skill for Pest PHP testing in Laravel projects only. Trigger whenever any test is being written, edited, fixed, or refactored — including fixing tests that broke after a code change, adding assertions, converting PHPUnit to Pest, adding datasets, and TDD workflows. Always activate when the user asks how to…

coollabsio/coolify · 171 tokens

write-vibe-tests

Write or refactor Mistral Vibe tests with proper decoupling. Use when adding behavior coverage, testing ports/adapters, replacing brittle mocks, creating fakes, adding characterization tests before refactors, or changing tests under tests/ for vibe/core, vibe/cli, vibe/acp, tools, config, sessions, skills, hooks, MCP…

mistralai/mistral-vibe · 80 tokens

composing-matchers

Build compound Gomega assertions by combining matchers — And/SatisfyAll (all pass), Or/SatisfyAny (any pass), Not (negate), WithTransform to map the actual before matching, Satisfy for an ad-hoc predicate, HaveValue to dereference pointers/interfaces, HaveField for struct fields and method results, HaveEach for every…

onsi/gomega · 136 tokens

adding-dbt-unit-test

Creates unit test YAML definitions that mock upstream model inputs and validate expected outputs. Use when adding unit tests for a dbt model or practicing test-driven development (TDD) in dbt.

dbt-labs/dbt-agent-skills · 44 tokens

testing-guide

Design, write, run, and diagnose Synergy tests with Bun, temporary Scope isolation, deterministic fixtures, and behavior-first assertions. Use for TDD, bug regressions, feature tests, migration tests, flaky tests, coverage, package tests, frontend tests, and selecting verification gates.

SII-Holos/synergy · 60 tokens

test

Generate tests and coverage plans. Triggers: "test", "generate tests and coverage plans.", "test skill".

boshu2/agentops · 25 tokens