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.

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 creating the implementation plan."

${languageInstruction}

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

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

Every plan MUST start with this header:

```markdown

[Feature Name] Implementation Plan

Goal: [One sentence describing what this builds]

Architecture: [2-3 sentences about approach]

Tech Stack: [Key technologies/libraries]

```

Task Structure

```markdown

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

```python def test_specific_behavior(): result = function(input) assert result == expected ```

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

```python def function(input): return expected ```

Step 4: Run test to verify it passes

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

Remember

• Exact file paths always
• Complete code in plan (not "add validation")
• Exact commands with expected output
• DRY, YAGNI

Arguments: ${args}