---
schemaVersion: 1
module: "atdd"
sourceSha: "f5122f94fbbe9475b72e2a36b04ae3e4ee98a0b7"
generatedAt: "2026-08-20T06:54:23.199Z"
---
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>
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# Agentic Test-Driven Development

Spec-driven development where E2E vision specs define target behavior. /atdd reads Playwright specs, iteratively builds app code until all tests pass, then ships.

- Category: workflow
- Status: stable
- Tags: testing, playwright, e2e, tdd, development
- Dependencies: none
- Presets: cloud-agent, full
- Context cost: ~444 tokens (always-loaded rule files)
- Last updated: 2026-08-04T10:19:19-04:00
- Available as a native plugin marketplace entry

## README

# ATDD Module

Agentic Test-Driven Development - build app code to pass E2E vision specs.

## What is ATDD?

ATDD is TDD applied at the E2E level for agent-driven development. Instead of writing code and then testing it, vision specs (Playwright test files) define the target behavior first, and agents iteratively build app code until all specs pass.

The cycle:
1. Vision specs exist (Playwright tests describing what the app SHOULD do)
2. Agent reads specs to understand expected behavior
3. Agent runs specs, sees what fails
4. Agent implements app code (never modifies specs)
5. Agent re-runs, sees progress
6. Repeat until all green
7. Commit, push, PR

## Usage

```bash
/atdd habits                     # Build code to pass habits vision specs
/atdd habits --issue 178         # Use existing issue
/atdd coaching --issue 180       # Build coaching feature
/atdd "principles journal"       # Multi-word feature name
```

## The ATDD Contract

- **Specs are immutable** - never modify test files during an ATDD run
- **Mocks are the API contract** - mock response shapes define the expected API format
- **UI expectations are the design spec** - test assertions define the UX
- **Work incrementally** - one failing test at a time, commit every 5-10 tests

## Expected Directory Structure

The command expects Playwright vision specs organized by feature:

```
e2e/
  fixtures/           # Shared test fixtures (mocks, helpers, personas)
  tests/
    auth/             # Auth feature vision specs
      login.spec.ts
      signup.spec.ts
    habits/           # Habits feature vision specs
      create.spec.ts
      list.spec.ts
      edit.spec.ts
    coaching/         # Coaching feature vision specs
      ...
```

## Relationship to Other Commands

- **`/test-vision`** - generates comprehensive vision specs for a repo (run this first)
- **`/e2e`** - generates a single feature's vision spec
- **`/atdd`** - consumes vision specs to build app code (run this after specs exist)

Pipeline: `/test-vision` or `/e2e` (write specs) -> `/atdd` (build code to pass specs)

## Manual Installation

```bash
mkdir -p ~/.claude/commands ~/.claude/rules
cp commands/atdd.md ~/.claude/commands/atdd.md
cp rules/atdd.md ~/.claude/rules/atdd.md
```


## Files

### rule

#### rules/atdd.md

```
# Agentic Test-Driven Development (ATDD)

## Methodology

ATDD uses E2E vision specs as the source of truth for feature behavior. Specs are written first (describing what the app SHOULD do), then agents build the app to match. This inverts the typical workflow: instead of writing code and then testing it, the tests define the target and the code is built to satisfy them.

## The ATDD Contract

1. **Specs are immutable** - Never modify test files during an ATDD run. If a spec seems wrong, flag it and move on - do not "fix" the spec to match current behavior.
2. **Mocks are the API contract** - Test fixtures mock API responses. These mock shapes ARE the expected API response format. If the real API returns a different shape, change the API, not the mock.
3. **UI expectations are the design spec** - If a test expects `getByRole("button", { name: /create habit/i })`, that button must exist with that accessible name. The test defines the UX.
4. **Work incrementally** - Don't try to make all tests pass at once. Pick one failing test, make it green, move to the next. Commit every 5-10 tests.
5. **Failing for the right reason** - A test that fails because the page doesn't load is different from one that fails because a button has the wrong label. Diagnose accurately.

## When to Use /atdd

- When vision E2E specs exist in `e2e/tests/{feature}/` subdirectories
- When building out new feature areas from scratch
- When iterating on existing features to match updated specs
- When onboarding a new agent to a feature area (specs document the expected behavior)

## When NOT to Use /atdd

- For bug fixes (use /debug instead)
- When no vision specs exist for the feature (write specs first with /test-vision or /e2e)
- For backend-only work with no UI component

```

### command

#### commands/atdd.md

````
---
description: Agentic Test-Driven Development - build app code to pass E2E vision specs. Reads Playwright tests, iteratively implements until all green, then ships.
allowed-tools: Bash, Read, Write, Edit, Glob, Grep, Agent
argument-hint: <feature> [--issue <number>]
---

# /atdd - Agentic Test-Driven Development

Build app code to pass E2E vision specs. Vision specs (Playwright test files) define what the app SHOULD do. This command reads the specs, builds/modifies app code until all tests pass, then ships.

**The ATDD cycle:**
1. Vision specs already exist (Playwright tests describing target behavior)
2. Agent reads specs to understand expected behavior
3. Agent runs specs, sees what fails
4. Agent implements/fixes app code (NEVER modifies spec files)
5. Agent re-runs, sees progress
6. Repeat until all green
7. Commit, push, PR

---

## Input

```
$ARGUMENTS
```

**Examples:**
```
/atdd habits
/atdd habits --issue 178
/atdd coaching --issue 180
/atdd "principles journal" --issue 181
```

---

## Phase 1: Orient

### 1.1 Parse Arguments

Parse `$ARGUMENTS`:
- Extract the feature name (single word like `habits` or quoted multi-word like `"principles journal"`)
- Extract `--issue <number>` if provided
- The feature name maps to a directory under `e2e/tests/`

### 1.2 Verify Spec Directory

Check that the spec directory exists:

```bash
ls e2e/tests/{feature}/*.spec.ts 2>/dev/null | head -20
```

If no spec files exist at `e2e/tests/{feature}/`:
- Report: "No vision specs found at `e2e/tests/{feature}/`. Write specs first (use /test-vision or /e2e), then run /atdd."
- STOP. Do not proceed without specs.

### 1.3 Issue & Branch

If `--issue` was provided, use that issue number. Otherwise, create one:

```bash
gh issue create --title "ATDD: Build web app to pass {feature} E2E vision specs" --label "enhancement" --body "Build app code to satisfy all E2E vision specs in e2e/tests/{feature}/."
```

Create the working branch:

```bash
git checkout -b {issue}-atdd-{feature} origin/main
```

### 1.4 Read All Specs

Read every spec file in the target directory to understand the expected behavior:

```bash
find e2e/tests/{feature}/ -name "*.spec.ts" -type f | sort
```

Read each file with the Read tool. Pay attention to:
- What routes/pages are tested
- What UI elements are expected (buttons, forms, headings, links)
- What user interactions are tested (clicks, form fills, navigation)
- What API responses are mocked (these define the API contract)
- What assertions define success (visible elements, URL changes, text content)

Also read any shared fixtures:

```bash
ls e2e/fixtures/*.ts 2>/dev/null
```

Read fixture files to understand mock data shapes, user personas, and state helpers.

### 1.5 Baseline Run

Run the specs to establish a baseline:

```bash
npx playwright test e2e/tests/{feature}/ --reporter=list 2>&1 | tail -40
```

Report: "X/Y tests passing. Starting ATDD loop."

If all tests already pass: report "All X tests already passing. Nothing to build." and STOP.

---

## Phase 2: Red-Green Loop

Work through failing tests systematically, not randomly. Prioritize in this order:

1. **Page load / route tests** - make sure pages render at all
2. **Structural tests** - headings, navigation, layout elements
3. **Interactive tests** - forms, buttons, user flows
4. **Edge cases** - empty states, error handling, loading states

### For each failing test:

**a. Read the test** - understand what it expects:
- What route does it navigate to?
- What UI elements must be visible?
- What interactions does it perform?
- What API mocks define the expected data shape?

**b. Identify app changes needed** - what must change:
- Missing route/page? Create it.
- Missing component? Create it.
- Missing API endpoint? Create it (matching the mock response shape).
- Wrong element text/role? Fix the component.
- Missing state management? Add it.

**c. Read relevant app code** - understand the current state:
- Check if the route exists in the router
- Check if the component exists
- Check if the API endpoint exists
- Understand the existing code patterns to follow

**d. Implement the minimum change** - make the test pass:
- Follow existing code patterns in the repo
- Don't over-engineer - just make the test green
- Match the mock data shapes exactly for API endpoints
- Use the exact accessible names the tests expect

**e. Run the specific test file**:

```bash
npx playwright test e2e/tests/{feature}/{file}.spec.ts --reporter=list 2>&1 | tail -30
```

**f. Iterate** - if still failing, read the error, diagnose, fix, re-run.

### Batch rules:

- After fixing a batch of related tests (or every 5-10 tests), run the full feature suite:
  ```bash
  npx playwright test e2e/tests/{feature}/ --reporter=list 2>&1 | tail -40
  ```
- Check for regressions - previously passing tests should still pass.
- Commit progress incrementally after each logical chunk of work:
  ```bash
  git add -A && git commit -m "#{issue}: ATDD {feature} - {X}/{Y} tests passing"
  ```

### Critical Rules:

- **NEVER modify files in `e2e/tests/` or `e2e/fixtures/`** - the specs define the target. If you change the specs to match your code, you've defeated the purpose.
- **Mocks define the API contract** - if a mock returns `{ habits: [...] }`, that's what the real API endpoint should return. Match the shape.
- **Tests define the UX** - if a test expects a button with label "Create Habit", create a button with that exact accessible name. Don't rename the test expectation.
- **If a spec seems wrong** - flag it in a code comment or commit message, but do NOT modify the spec. Move on to the next test.

---

## Phase 3: Verify

After all feature tests are green, run the full verification suite:

### 3.1 Full Feature Suite

```bash
npx playwright test e2e/tests/{feature}/ --reporter=list 2>&1 | tail -40
```

All tests must pass. If any fail, return to Phase 2 for those tests.

### 3.2 Lint

```bash
npm run lint 2>&1 | tail -20
```

Fix any lint errors in files you created or modified.

### 3.3 Type Check

```bash
npm run type-check 2>&1 | tail -20
```

Fix any type errors.

### 3.4 Unit Tests

```bash
npm run test:run 2>&1 | tail -20
```

Ensure no unit tests were broken by the changes.

### 3.5 Final Commit

If there are uncommitted changes after verification fixes:

```bash
git add -A && git commit -m "#{issue}: ATDD {feature} - all tests passing, verification clean"
```

---

## Phase 4: Ship

### 4.1 Push

```bash
git push -u origin {branch-name}
```

### 4.2 Create PR

```bash
gh pr create --title "#{issue}: ATDD - {feature} vision specs passing" --body "$(cat <<'PREOF'
## Summary

ATDD implementation for **{feature}** - built app code to pass all E2E vision specs.

## Results

- **Baseline**: {X}/{Y} tests passing
- **Final**: {Y}/{Y} tests passing (all green)

## What was implemented

{Bulleted list of what was created/changed:}
- Created {route/page} at {path}
- Created {component} at {path}
- Added {API endpoint} at {path}
- Modified {file} to {what changed}
- ...

## Spec files consumed (not modified)

{List the spec files that drove this implementation}

Closes #{issue}
PREOF
)"
```

### 4.3 Report

```
ATDD Complete: {feature}

Baseline: {X}/{Y} tests passing
Final:    {Y}/{Y} tests passing

Branch: {branch-name}
PR: {PR URL}

Files created:  {N}
Files modified: {N}
Commits:        {N}
```

````