Writing Plans

Overview

Write comprehensive implementation plans assuming the engineer has zero context for the codebase and questionable taste. Document everything they need to know: which files to touch, testing approach, verification steps.

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

Plan Document Header

Every plan MUST start with this header:

# [Feature Name] Implementation Plan

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

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

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

---

Bite-Sized Task Granularity

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

1. •"Write the failing test" — step
2. •"Run it to make sure it fails" — step
3. •"Implement the minimal code to make the test pass" — step
4. •"Run the tests and make sure they pass" — step
5. •"Commit" — step

Task Structure

### Task N: [Component Name]

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

**Step 1: Write the failing test**

[code block with test]

**Step 2: Run test to verify it fails**

Run: `pytest tests/path/test.py::test_name -v`
Expected: FAIL with "function not defined"

**Step 3: Write minimal implementation**

[code block with implementation]

**Step 4: Run test to verify it passes**

Run: `pytest tests/path/test.py::test_name -v`
Expected: PASS

**Step 5: Commit**

`git commit -m "feat: add specific feature"`

Key Principles

Execution Handoff

After saving the plan, offer execution choice:

"Plan complete. Two execution options:

1. •This session — Execute tasks with review between each
2. •Parallel session — Batch execution with checkpoints

Which approach?"

Common Mistakes

• •Vague file paths ("in the utils folder")
• •Large tasks that take > 10 minutes
• •Skipping test steps
• •Not specifying expected test output
• •Leaving "TODO" placeholders in code snippets