# Handoff Report: Milestone M2 Progression Service Drop-in Fixes

- **Agent**: `explorer_m2_progression_1_gen2`
- **Archetype / Role**: `teamwork_preview_explorer`
- **Working Directory**: `c:\Projects\FreeExile\.agents\teamwork\explorer_m2_progression_1_gen2`
- **Target File**: `server/world/level_progression_service.py`
- **Recipient**: `orchestrator_4` (`6f4a2aa2-4315-4660-8cb7-8352a7220c95`)
- **Date**: 2026-10-01T03:15:00Z
- **Handoff Type**: Hard

---

## 1. Observation

1. **Defect 1 — Level 100 Cumulative EXP Overflow**:
   - Location: `server/world/level_progression_service.py:253`.
   - Code: `cumulative_exp=player.cumulative_exp + exp_awarded,`
   - Test Command:
     ```powershell
     python -c "from server.world.level_progression_service import LevelProgressionService; s = LevelProgressionService(); s.set_player_state('test', level=99, current_exp=s.get_delta_exp(99) - 10); s.award_monster_exp('test', 100, 100, 1000000); info = s.get_level_info('test'); b100 = s.get_benchmark(100); print('diff:', info.cumulative_exp - b100.cumulative_exp)"
     ```
   - Verbatim Output: `diff: 999990`.
   - Benchmark: `b100.cumulative_exp` evaluates to `24,285,477,315`. Excess EXP in the level-up strike overflows past the benchmark ceiling.

2. **Defect 2 — Level 100 Death Listener & Counter Silencing**:
   - Location: `server/world/level_progression_service.py:298-300`.
   - Code:
     ```python
     player = self.get_player_state(player_id)
     if player.level >= 100:
         return self._build_death_result(player, 0, 0.0, player.current_exp)
     ```
   - Test Command:
     ```powershell
     python -c "from server.world.level_progression_service import LevelProgressionService; s = LevelProgressionService(); s.set_player_state('p100', level=100); calls = []; s.add_death_penalty_listener(lambda r: calls.append(r)); s.apply_death_penalty('p100'); print('deaths:', s.get_level_info('p100').deaths_count, 'events:', len(calls))"
     ```
   - Verbatim Output: `deaths: 0 events: 0`.
   - Premature early return prevented state persistence (`deaths_count = player.deaths_count + 1`) and bypassed `for listener in self._death_listeners: listener(result)`.

3. **Defect 3 — Negative EXP Injection**:
   - Location: `server/world/level_progression_service.py:151-158, 170-181`.
   - Test Command:
     ```powershell
     python -c "from server.world.level_progression_service import LevelProgressionService; s = LevelProgressionService(); s.set_player_state('p', level=10, current_exp=100); s.award_monster_exp('p', 10, base_exp=-100); print(s.get_level_info('p').current_exp)"
     ```
   - Verbatim Output: `0` (or negative if starting below 100). `raw_exp` lacked `max(0, ...)` boundary clamping.

4. **Validation of Proposed Drop-in Implementation (`proposed_level_progression_service.py`)**:
   - Tool Command: `python .agents/teamwork/explorer_m2_progression_1_gen2/verify_fixes.py`
   - Verbatim Output:
     ```text
     [TEST 1 PASS] b100.cumulative_exp == 24285477315
     [TEST 2 PASS] Level 100 cumulative EXP strictly clamped with ZERO overflow
     [TEST 3 PASS] Level 100 death listener notified and deaths_count incremented
     [TEST 4 PASS] Negative EXP sanitized to 0
     [TEST 5 PASS] Total lines = 340 <= 350 (Soft Cap)
       Function __init__: 11 lines (OK)
       Function get_benchmark: 3 lines (OK)
       Function get_canonical_benchmark: 3 lines (OK)
       Function get_delta_exp: 6 lines (OK)
       Function get_death_penalty_ratio: 11 lines (OK)
       Function calculate_level_gap_multiplier: 10 lines (OK)
       Function get_player_state: 19 lines (OK)
       Function set_player_state: 30 lines (OK)
       Function get_level_info: 3 lines (OK)
       Function add_level_up_listener: 3 lines (OK)
       Function add_death_penalty_listener: 3 lines (OK)
       Function award_monster_exp: 25 lines (OK)
       Function _resolve_award_args: 20 lines (OK)
       Function _ensure_player_for_award: 14 lines (OK)
       Function _build_level_100_award_result: 16 lines (OK)
       Function _compute_level_advancement: 14 lines (OK)
       Function _apply_exp_gain: 47 lines (OK)
       Function _dispatch_level_up: 18 lines (OK)
       Function apply_death_penalty: 25 lines (OK)
       Function _build_death_result: 13 lines (OK)
     [TEST 6 PASS] All functions <= 50 lines (AST Check)
     ALL 6 CHECKS PASSED PERFECTLY!
     ```
   - Regression Unit Tests (`run_unit_tests.py`): `33 passed in 0.17s`.
   - Regression E2E Tests (`run_e2e_tests.py`): `22 passed in 0.12s`.
   - Strict Static Type Check: `python -m mypy --explicit-package-bases --follow-imports=silent .agents/teamwork/explorer_m2_progression_1_gen2/proposed_level_progression_service.py` -> `Success: no issues found in 1 source file`.

---

## 2. Logic Chain

1. **Level 100 Cumulative EXP Clamp (From Observation 1 & 4)**:
   - When a character advances to Level 100, `curr_lvl >= 100`.
   - Clamping `cumulative_exp = min(self.get_canonical_benchmark(100).cumulative_exp, cumulative_exp)` and setting `exp_to_next_level = 0, current_exp = 0` guarantees that `cumulative_exp` can never exceed `24,285,477,315` regardless of how much excess EXP was generated by the fatal blow.
   - Performing identical clamping in `set_player_state()` guarantees that administrative or testing restoration cannot introduce benchmark overflow.
2. **Level 100 Death Listener & Counter (From Observation 2 & 4)**:
   - In `apply_death_penalty()`, removing the early return allows execution to proceed to lines 301-322.
   - For `level == 100`, `get_death_penalty_ratio(100)` returns `0.0`, and `get_delta_exp(100)` returns `0`.
   - `nominal_loss = 0`, `exp_lost = 0`, `new_exp = 0`.
   - `self._players[player_id]` is updated with `deaths_count = player.deaths_count + 1`, and `_death_listeners` is notified with `DeathPenaltyResult(level=100, exp_lost=0, penalty_ratio=0.0, ...)`.
   - Telemetry, death broadcast loggers, and hardcore permadeath migration listeners now operate consistently across all levels (1 to 100).
3. **EXP Non-Negative Sanitization (From Observation 3 & 4)**:
   - Clamping `base_exp` and `raw_exp` to `max(0, ...)` eliminates negative experience inputs, preventing unintended experience loss during kill awards.
4. **Hygiene & Line Budget (From Observation 4)**:
   - The refactored file has **340 lines**, strictly under the 350-line soft cap and 500-line hard cap.
   - The longest function (`_apply_exp_gain`) is 47 lines, strictly complying with the $\le 50$ lines AST restriction.

---

## 3. Caveats

1. **Read-Only Explorer Constraint**: In accordance with the Teamwork explorer protocol, no source files were directly edited. All remediations are provided as complete drop-in files (`proposed_level_progression_service.py`) and a unified diff patch (`patch_level_progression_service.patch`) for immediate application by the worker.
2. **Combat Engine Separation**: Reviewers noted corpse-hitting overkill and phantom evasion issues in `server/world/combat_engine.py`. Those concerns are isolated to `combat_engine.py` and do not impair the correctness of the fixes for `server/world/level_progression_service.py`.

---

## 4. Conclusion

The exact drop-in code fixes for `server/world/level_progression_service.py` have been fully formulated, tested, and validated. They:
1. Guarantee zero overflow past `24,285,477,315` EXP for Level 100.
2. Enable death listener dispatch and death counter incrementing for Level 100 characters with 0 EXP penalty.
3. Sanitize negative base experience to 0.
4. Strictly satisfy the 340-line count budget ($\le 350$ soft cap) and function AST length limit ($\le 50$ lines).

The implementation is immediately ready for worker application.

---

## 5. Verification Method

To independently verify the drop-in fix when applied to `server/world/level_progression_service.py`:

1. **Verify Level 100 Cumulative EXP Cap (Zero Overflow)**:
   ```powershell
   python -c "from server.world.level_progression_service import LevelProgressionService; s = LevelProgressionService(); s.set_player_state('t', level=99, current_exp=s.get_delta_exp(99) - 10); s.award_monster_exp('t', 100, 100, 1000000); info = s.get_level_info('t'); b100 = s.get_canonical_benchmark(100); assert info.cumulative_exp == b100.cumulative_exp == 24285477315; assert info.exp_to_next_level == 0; print('ZERO OVERFLOW VERIFIED')"
   ```
   *Expected*: `ZERO OVERFLOW VERIFIED`.

2. **Verify Level 100 Death Listener & Telemetry**:
   ```powershell
   python -c "from server.world.level_progression_service import LevelProgressionService; s = LevelProgressionService(); s.set_player_state('t', level=100); events = []; s.add_death_penalty_listener(lambda r: events.append(r)); res = s.apply_death_penalty('t'); assert s.get_level_info('t').deaths_count == 1; assert len(events) == 1; assert res.exp_lost == 0; assert res.penalty_ratio == 0.0; print('DEATH TELEMETRY VERIFIED')"
   ```
   *Expected*: `DEATH TELEMETRY VERIFIED`.

3. **Verify Negative EXP Sanitization**:
   ```powershell
   python -c "from server.world.level_progression_service import LevelProgressionService; s = LevelProgressionService(); s.set_player_state('t', level=10, current_exp=100); res = s.award_monster_exp('t', 10, base_exp=-100); assert res.exp_awarded == 0; assert s.get_level_info('t').current_exp == 100; print('NEGATIVE EXP SANITIZED')"
   ```
   *Expected*: `NEGATIVE EXP SANITIZED`.

4. **Verify Line Budget and Function Caps**:
   ```powershell
   python -c "import ast; p = r'server/world/level_progression_service.py'; lines = open(p, encoding='utf-8').readlines(); assert len(lines) <= 350, f'File lines {len(lines)} > 350'; tree = ast.parse(''.join(lines)); [assert_(node.end_lineno - node.lineno + 1 <= 50, f'{node.name} > 50') for node in ast.walk(tree) if isinstance(node, ast.FunctionDef)]; print('HYGIENE LIMITS VERIFIED')"
   ```
   *Expected*: `HYGIENE LIMITS VERIFIED`.

5. **Run Full Test Suite**:
   ```powershell
   pytest tests/unit/test_level_progression_service.py -v
   pytest tests/e2e/test_level_progression_e2e.py -k "test_f03 or test_f04 or test_f05" -v
   python -m mypy --explicit-package-bases --follow-imports=silent server/world/level_progression_service.py
   python tools/lint/check_code_and_doc_hygiene.py --strict
   ```