1. PRE-TASK
   - Verify dependencies complete
   - Review acceptance criteria
   - Create feature branch (optional)
   - Set up task context

2. IMPLEMENT (TDD Cycle)
   - Write failing test (RED)
   - Implement minimal code (GREEN)
   - Refactor for quality (REFACTOR)
   - Repeat until all criteria met

3. VALIDATE
   - All tests passing?
   - All acceptance criteria met?
   - Code quality checks pass?
   - Documentation updated?

4. CHECKPOINT
   - Mark task complete IMMEDIATELY (do NOT batch)
   - Update execution state
   - Report progress
   - Identify blockers

# Write test that fails
def test_user_authentication():
    user = authenticate("user@example.com", "password")
    assert user.is_authenticated
# Run test → FAILS (feature not implemented)

# Implement minimal code to pass
def authenticate(email, password):
    # Simplest implementation
    user = User.find_by_email(email)
    if user and user.check_password(password):
        user.is_authenticated = True
        return user
    return None
# Run test → PASSES

# Improve code quality
def authenticate(email: str, password: str) -> Optional[User]:
    """Authenticate user with email and password."""
    user = User.find_by_email(email)
    if user is None:
        return None

    if not user.check_password(password):
        return None

    user.mark_authenticated()
    return user
# Run test → STILL PASSES

- [ ] All acceptance criteria met
- [ ] All tests passing (unit + integration)
- [ ] Code linted (no warnings)
- [ ] Type checking passes (if applicable)
- [ ] Documentation updated
- [ ] No regression in other components

# Run quality gates
make lint          # Linting passes
make typecheck     # Type checking passes
make test          # All tests pass
make coverage      # Coverage threshold met

{
  "plan_file": "docs/implementation-plan.md",
  "started_at": "2026-01-02T10:00:00Z",
  "last_checkpoint": "2026-01-02T14:30:22Z",
  "current_sprint": "Sprint 1",
  "current_phase": "Phase 1",
  "tasks": {
    "TASK-001": {
      "status": "complete",
      "started_at": "2026-01-02T10:05:00Z",
      "completed_at": "2026-01-02T10:50:00Z",
      "duration_minutes": 45,
      "acceptance_criteria_met": true,
      "tests_passing": true
    },
    "TASK-002": {
      "status": "in_progress",
      "started_at": "2026-01-02T14:00:00Z",
      "progress_percent": 60,
      "blocker": null
    }
  },
  "metrics": {
    "tasks_complete": 15,
    "tasks_total": 40,
    "completion_percent": 37.5,
    "velocity_tasks_per_day": 3.2,
    "estimated_completion_date": "2026-02-15"
  },
  "blockers": []
}

# Daily Standup - [Date]

## Yesterday
- ✅ [Task] ([duration])
- ✅ [Task] ([duration])

## Today
- 🔄 [Task] ([progress]%)
- 📋 [Task] (planned)

## Blockers
- [Blocker] or None

## Metrics
- Sprint progress: [X/Y] tasks ([%]%)
- [Status message]

# Sprint [N] Progress Report

**Dates**: [Start] - [End]
**Goal**: [Sprint objective]

## Completed ([X] tasks)
- [Task list]

## In Progress ([Y] tasks)
- [Task] ([progress]%)

## Blocked ([Z] tasks)
- [Task]: [Blocker description]

## Burndown
- Day 1: [N] tasks remaining
- Day 5: [M] tasks remaining ([status])
- Estimated completion: [Date] ([delta])

## Risks
- [Risk] or None identified

## Blocker: [TASK-XXX] - [Issue]

**Symptom**: [What's happening]

**Impact**: [Which tasks/timeline affected]

**Attempted Solutions**:
1. [Solution 1] - [Result]
2. [Solution 2] - [Result]

**Recommendation**: [Proposed path forward]

**Decision Needed**: [What needs to be decided]

**Verification:** Run `pytest -v` to verify tests pass.
     /\
    /E2E\      Few, slow, expensive
   /------\
  /  INT  \    Some, moderate speed
 /----------\
/   UNIT    \  Many, fast, cheap

**Verification:** Run `pytest -v` to verify tests pass.
Velocity = Tasks completed / Days elapsed
Estimated completion = Tasks remaining / Velocity
On track? = Estimated completion <= Sprint end date