# Tasks: Add Milestone Type to List Milestones Tool

**Input**: Design documents from `/specs/001-schedule-tools/`
**Prerequisites**: plan.md (required), spec.md (required), research.md, data-model.md, contracts/

**Tests**: TDD is mandated by constitution - tests MUST be written and fail before implementation.

**Scope**: Enhancement to existing implementation - add `milestone_type` (start/finish) to milestone query responses per spec clarification.

**Change Summary**: The spec was updated to require that the `list_milestones` tool return both Start Milestones and Finish Milestones with their `milestone_type` field (start/finish for milestones, null otherwise).

## Format: `[ID] [P?] [Story] Description`

- **[P]**: Can run in parallel (different files, no dependencies)
- **[Story]**: Which user story this task belongs to (US4 = Query Project Summary)
- Include exact file paths in descriptions

## Path Conventions

- **Source**: `src/xer_mcp/`
- **Tests**: `tests/`
- **Config**: `pyproject.toml`

---

## Phase 1: Setup (Schema Enhancement)

**Purpose**: Add milestone_type column needed for distinguishing start vs finish milestones

- [x] T001 Update activities table schema to add milestone_type column in src/xer_mcp/db/schema.py

---

## Phase 2: Foundational (Parser Enhancement)

**Purpose**: Parse milestone_type from TASK table and store in database

**⚠️ CRITICAL**: Must complete before milestone queries can return the type

### Tests

- [x] T002 [P] Unit test for TASK handler parsing milestone_type in tests/unit/test_table_handlers.py (verify milestone_type extracted for TT_Mile activities)

### Implementation

- [x] T003 Update TASK table handler to parse milestone_type field in src/xer_mcp/parser/table_handlers/task.py
- [x] T004 Update database loader to store milestone_type when inserting activities in src/xer_mcp/db/loader.py

**Checkpoint**: milestone_type is now parsed and stored - queries can begin

---

## Phase 3: User Story 4 - Add Milestone Type to Queries (Priority: P3)

**Goal**: Return `milestone_type` field in milestone query responses

**Independent Test**: Load XER file, query milestones, verify milestone_type is present and correctly identifies start vs finish milestones

### Tests for User Story 4

> **NOTE: Write these tests FIRST, ensure they FAIL before implementation**

- [x] T005 [P] [US4] Update contract test to verify milestone_type field in list_milestones response in tests/contract/test_list_milestones.py
- [x] T006 [P] [US4] Add test case verifying both start and finish milestones are returned with correct types in tests/contract/test_list_milestones.py

### Implementation for User Story 4

- [x] T007 [US4] Update query_milestones function to SELECT and return milestone_type in src/xer_mcp/db/queries.py
- [x] T008 [US4] Update list_milestones tool docstring to document milestone_type field in src/xer_mcp/tools/list_milestones.py

**Checkpoint**: milestone_type now included in milestone responses

---

## Phase 4: Documentation & Contracts

**Purpose**: Update contracts and documentation to reflect the new field

- [x] T009 [P] Update ActivitySummary schema to include optional milestone_type field in specs/001-schedule-tools/contracts/mcp-tools.json
- [x] T010 [P] Update Activity entity in data-model.md to include milestone_type field in specs/001-schedule-tools/data-model.md
- [x] T011 Update quickstart.md milestone example to show milestone_type in output in specs/001-schedule-tools/quickstart.md

---

## Phase 5: Polish & Validation

**Purpose**: Verify integration and ensure no regressions

- [x] T012 Run all tests to verify no regressions: uv run pytest tests/
- [x] T013 Run ruff check and fix any linting issues: uv run ruff check src/
- [x] T014 Validate list_milestones output matches updated contract schema

---

## Dependencies & Execution Order

### Phase Dependencies

```
Phase 1 (Schema)
    │
    ▼
Phase 2 (Parser)
    │
    ▼
Phase 3 (Queries) ← MAIN WORK
    │
    ▼
Phase 4 (Docs) ← Can run in parallel with Phase 3
    │
    ▼
Phase 5 (Polish)
```

### Task Dependencies Within Phases

```
T001 (Schema)
    │
    ├── T002 (Parser test)
    │
    ▼
T003 (Parser impl) ← depends on T001
    │
    ▼
T004 (Loader) ← depends on T003
    │
    ├── T005, T006 (Contract tests)
    │
    ▼
T007 (Query impl) ← depends on T004
    │
    ▼
T008 (Tool docs)
```

### Parallel Opportunities

**Phase 2 Tests + Phase 3 Tests** (can write all tests in parallel):
```bash
Task T002: "Unit test for TASK handler parsing milestone_type"
Task T005: "Update contract test for list_milestones"
Task T006: "Add test for start/finish milestone types"
```

**Phase 4 Documentation** (can run in parallel):
```bash
Task T009: "Update ActivitySummary schema"
Task T010: "Update Activity entity in data-model.md"
Task T011: "Update quickstart.md example"
```

---

## Implementation Details

### Milestone Type Determination

In Primavera P6, milestones are identified by `task_type = 'TT_Mile'`. The distinction between Start and Finish milestones is typically:

1. **XER Field**: Check for `milestone_type` field in TASK table (values: `MS_Start`, `MS_Finish`)
2. **Fallback**: If field not present, can infer from dates:
   - Start milestone: Has only `target_start_date` (or start = end)
   - Finish milestone: Has only `target_end_date` (or represents completion)

### Schema Change

```sql
-- Add to activities table
milestone_type TEXT  -- 'start', 'finish', or NULL for non-milestones
```

### Query Change

```sql
SELECT task_id, task_code, task_name,
       target_start_date, target_end_date,
       status_code, milestone_type
FROM activities
WHERE task_type = 'TT_Mile'
ORDER BY target_start_date, task_code
```

### Response Format

```json
{
  "milestones": [
    {
      "task_id": "M001",
      "task_code": "MS-START",
      "task_name": "Project Start",
      "milestone_type": "start",
      "target_start_date": "2026-01-15T08:00:00",
      "target_end_date": "2026-01-15T08:00:00",
      "status_code": "TK_Complete"
    },
    {
      "task_id": "M002",
      "task_code": "MS-END",
      "task_name": "Project Complete",
      "milestone_type": "finish",
      "target_start_date": "2026-06-30T17:00:00",
      "target_end_date": "2026-06-30T17:00:00",
      "status_code": "TK_NotStart"
    }
  ]
}
```

---

## Summary

| Phase | Tasks | Focus |
|-------|-------|-------|
| Setup | 1 | Schema update |
| Foundational | 3 | Parser enhancement |
| US4 Implementation | 4 | Milestone type in queries |
| Documentation | 3 | Contracts & docs |
| Polish | 3 | Validation |
| **Total** | **14** | |

### Task Distribution by Type

| Type | Count | IDs |
|------|-------|-----|
| Schema | 1 | T001 |
| Tests | 3 | T002, T005, T006 |
| Implementation | 4 | T003, T004, T007, T008 |
| Documentation | 3 | T009, T010, T011 |
| Validation | 3 | T012, T013, T014 |

### Independent Test Criteria

| Verification | How to Test |
|--------------|-------------|
| milestone_type parsed | Unit test: parse XER with milestones, verify milestone_type extracted |
| milestone_type in response | Contract test: call list_milestones, verify milestone_type field present |
| Start/Finish distinction | Contract test: verify "Project Start" has type="start", "Project Complete" has type="finish" |

### MVP Scope

Complete through T008 for minimal viable milestone_type implementation.

---

## Notes

- [P] tasks = different files, no dependencies on incomplete tasks
- [US4] = User Story 4 (Query Project Summary - milestones)
- Constitution mandates TDD: write tests first, verify they fail, then implement
- milestone_type is stored in database, not computed at query time
- For non-milestone activities, milestone_type should be NULL
- Commit after each task or logical group