writing-plans

name	writing-plans
description	Use when you have a spec or requirements for a multi-step task, before touching code. Writes comprehensive implementation plans with exact file paths, code, tests, and bite-sized tasks. Triggers on "create a plan", "implementation plan", "write a plan", "task breakdown", or when given specs/requirements for a multi-step change.

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. TDD. 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.

Announce at start: "I'm using the writing-plans skill to create the implementation plan."

Save plans to: docs/plans/YYYY-MM-DD-<feature-name>.md

Scope Check

If the spec covers multiple independent subsystems, suggest breaking into separate plans — one per subsystem. Each plan should produce working, testable software on its own.

File Structure

Before defining tasks, map out which files will be created or modified and what each one is responsible for.

• Design units with clear boundaries and well-defined interfaces.
• Prefer smaller, focused files over large ones that do too much.
• Files that change together should live together.
• In existing codebases, follow established patterns.

Bite-Sized Task Granularity

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

• "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

Plan Document Header

# [Feature Name] Implementation Plan

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

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

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

---

Task Structure

### Task N: [Component Name]

**Files:**
- Create: `exact/path/to/file.js`
- Modify: `exact/path/to/existing.js:123-145`
- Test: `tests/exact/path/to/test.js`

- [ ] **Step 1: Write the failing test**
```js
test('specific behavior', () => {
    const result = functionUnderTest(input);
    expect(result).toBe(expected);
});

• Step 2: Run test to verify it fails Run: npm test -- tests/path/test.js Expected: FAIL

• Step 3: Write minimal implementation

export function functionUnderTest(input) {
    return expected;
}

• Step 4: Run test to verify it passes Run: npm test -- tests/path/test.js Expected: PASS

• Step 5: Commit

git add tests/path/test.js src/path/file.js
git commit -m "feat: add specific feature"

## No Placeholders

Every step must contain actual content. These are **plan failures** — never write them:
- "TBD", "TODO", "implement later", "fill in details"
- "Add appropriate error handling" / "add validation" / "handle edge cases"
- "Write tests for the above" (without actual test code)
- "Similar to Task N" (repeat the code)
- Steps that describe what to do without showing how

## Remember
- Exact file paths always
- Complete code in every step
- Exact commands with expected output
- DRY, YAGNI, TDD, frequent commits

## Self-Review

After writing the complete plan:

1. **Spec coverage:** Can you point to a task for each requirement? List any gaps.
2. **Placeholder scan:** Search for red flags from the "No Placeholders" section.
3. **Type consistency:** Do types, signatures, and names match across tasks?

Fix issues inline. If you find a spec requirement with no task, add the task.

## Execution Handoff

After saving the plan:

**"Plan complete and saved to `docs/plans/<filename>.md`.**

To execute, open a new session or continue in this one. Each task in the plan is self-contained and can be implemented independently. Tasks are ordered by dependency — work sequentially or delegate parallel tasks."

Source: Adapted from obra/superpowers writing-plans skill