Writing Plans

Overview

Write comprehensive implementation plans assuming the engineer has zero context for our codebase and questionable taste. Document everything they need to know: which files to touch for each task, code, testing, docs they might need to check, how to test it. Give them the whole plan as bite-sized tasks. DRY. YAGNI. Frequent commits.

Assume they are a skilled developer, but know almost nothing about our toolset or problem domain. Assume they don't know good test design very well.

Mode Selection

Ask the user before writing the plan:

"Which development approach do you prefer?

• •TDD - Test first, then implementation (red-green-refactor cycle)
• •Non-TDD - Direct implementation without tests"

If Non-TDD selected, also ask:

"How should work be verified for each task?

• •Manual testing (describe what to check)
• •Run a command (e.g., pnpm run build, pnpm run lint)
• •Visual inspection
• •Other (describe)"

Document the chosen verification method in the plan header.

Ask about commit strategy:

"Should commits be included in the plan?

• •Yes - Include commit step after each task (recommended for tracking progress)
• •No - No commit steps (useful when experimenting or for a single final commit)"

Bite-Sized Task Granularity

Each step is one action (2-5 minutes):

Mode TDD:

• •"Write the failing test" - step
• •"Run it to make sure it fails" - step
• •"Implement the minimal code to make the test pass" - step
• •"Run the tests and make sure they pass" - step
• •"Commit" - step

Mode Non-TDD:

• •"Implement the functionality" - step
• •"Verify using [verification method from plan]" - step
• •"Commit" - step

Plan Document Header

Every plan MUST start with this header:

# [Feature Name] Implementation Plan

> **For Claude:** REQUIRED SUB-SKILL: Use executing-plans to implement this plan task-by-task.

**Goal:** [One sentence describing what this builds]

**Architecture:** [2-3 sentences about approach]

**Tech Stack:** [Key technologies/libraries]

**Mode:** TDD / Non-TDD

**Commits:** Yes / No

**Verification Method (Non-TDD only):** [How to verify each task - command, manual steps, etc.]

---

Task Structure

Template TDD

### Task N: [Component Name]

**Files:**

- Create: `exact/path/to/file.ts`
- Modify: `exact/path/to/existing.ts:123-145`
- Test: `tests/exact/path/to/file.spec.ts`

**Step 1: Write the failing test**

```typescript
describe('specificBehavior', () => {
  it('should return expected result', () => {
    const result = myFunction(input);
    expect(result).toBe(expected);
  });
});
```

Step 2: Run test to verify it fails

Run: pnpm run test tests/path/file.spec.ts Expected: FAIL with "myFunction is not defined"

Step 3: Write minimal implementation

export function myFunction(input: string): string {
  return expected;
}

Step 4: Run test to verify it passes

Run: pnpm run test tests/path/file.spec.ts Expected: PASS

Step 5: Commit (if Commits = Yes)

Use @committing skill

### Template Non-TDD

```markdown
### Task N: [Component Name]

**Files:**
- Create: `exact/path/to/file.ts`
- Modify: `exact/path/to/existing.ts:123-145`

**Step 1: Implement the functionality**

```typescript
export function myFunction(input: string): string {
  return expected;
}

Step 2: Verify

Run: [Verification method from plan header] Expected: [Expected result]

Step 3: Commit (if Commits = Yes)

Use @committing skill

## Remember
- Exact file paths always
- Complete code in plan (not "add validation")
- Exact commands with expected output
- Reference relevant skills with @ syntax
- DRY, YAGNI, verification before commit
- If Commits = Yes: frequent commits after each task

## Execution Handoff

After saving the plan, offer execution choice:

**"Plan complete. Two execution options:**

**1. Subagent-Driven (this session)** - I dispatch fresh subagent per task, review between tasks, fast iteration

**2. Parallel Session (separate)** - Open new session with executing-plans, batch execution with checkpoints

**Which approach?"**

**If Subagent-Driven chosen:**
- **REQUIRED SUB-SKILL:** Use subagent-driven-development
- Stay in this session
- Fresh subagent per task + code review

**If Parallel Session chosen:**
- **REQUIRED SUB-SKILL:** New session uses executing-plans