Planning Implementation

Bite-Sized Task Granularity: Each step is one atomic action:

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

Plan File Location: docs/plans/YYYY-MM-DD-<feature-name>.md

Plan Header Template:

# [Feature Name] Implementation Plan
**Goal:** [One sentence describing what this builds]
**Architecture:** [2-3 sentences about approach]
**Tech Stack:** [Key technologies/libraries]

Task Structure Template:

### Task N: [Component Name]
**Files:**
- Create: `exact/path/to/file.py`
- Modify: `exact/path/to/existing.py:123-145`

**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

def function(input):
    return expected

Step 4: Run test to verify it passes

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

Step 5: Commit

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

**Principals**:
- Exact file paths always.
- Complete code in plan (not "add validation").
- Exact commands with expected output.
- DRY, YAGNI, TDD.