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# Implementation Summary

**Session ID**: `phase22-session03-legion-enemy-reducer` **Package**: apps/web **Completed**: 2026-07-05 **Duration**: 0.25 hours

***

## Overview

Implemented Phase 22 Legion enemy reduction in the web game projection. The reducer now folds dev-health, task-pressure, and failed-tool events into bounded serializable enemy aggregate state while preserving replay honesty, privacy boundaries, alert-focus priority, and same-reference no-op behavior.

***

## Deliverables

### Files Created

| File                                                                                  | Purpose                                               | Lines |
| ------------------------------------------------------------------------------------- | ----------------------------------------------------- | ----- |
| `.spec_system/specs/phase22-session03-legion-enemy-reducer/spec.md`                   | Session scope, requirements, and implementation plan. | \~199 |
| `.spec_system/specs/phase22-session03-legion-enemy-reducer/tasks.md`                  | Completed 20-task checklist.                          | \~66  |
| `.spec_system/specs/phase22-session03-legion-enemy-reducer/implementation-notes.md`   | Task-by-task implementation evidence.                 | \~475 |
| `.spec_system/specs/phase22-session03-legion-enemy-reducer/code-review.md`            | Code review and repair report.                        | \~79  |
| `.spec_system/specs/phase22-session03-legion-enemy-reducer/security-compliance.md`    | Security and GDPR review report.                      | \~75  |
| `.spec_system/specs/phase22-session03-legion-enemy-reducer/validation.md`             | Validation report with PASS result.                   | \~205 |
| `.spec_system/specs/phase22-session03-legion-enemy-reducer/IMPLEMENTATION_SUMMARY.md` | Closeout summary.                                     | \~70  |

### Files Modified

| File                                        | Changes                                                                                                               |
| ------------------------------------------- | --------------------------------------------------------------------------------------------------------------------- |
| `apps/web/src/lib/gameProjection.ts`        | Added bounded Legion reducer helpers and event folding for skirmishers, ram, gremlins, siege, and wraiths.            |
| `apps/web/tests/gameProjection.test.ts`     | Added reducer tests for enemy folding, replay no-accumulation, focus priority, parser guards, and privacy exclusions. |
| `.spec_system/state.json`                   | Marked Session 03 complete, cleared current session, and appended completion history.                                 |
| `.spec_system/PRD/phase_22/PRD_phase_22.md` | Updated progress tracker to 3/8 sessions complete and set next upcoming session to Session 04.                        |
| `apps/web/package.json`                     | Bumped package version from 0.1.59 to 0.1.60.                                                                         |
| `package-lock.json`                         | Bumped the `apps/web` workspace lockfile version from 0.1.59 to 0.1.60.                                               |

***

## Technical Decisions

1. **Aggregate-only enemy state**: Stored bounded refs, counters, levels, and timestamps instead of raw failure messages, tool previews, prompts, command output, paths, file contents, provider payloads, tokens, or secrets.
2. **Snapshot versus accumulation split**: Treated `ts_errors` and `build_fix` as reconciliation or clear signals while keeping replay traffic from increasing lint pressure or wraith stacks.
3. **Privacy-safe identity handling**: Preserved safe plan, task, and hero ids, but hashed unsafe path-like, token-like, secret-like, or overlong ids before persistence.
4. **Derived focus only**: Routed enemy mutations through existing projection finalization so `alertFocus` remains derived by priority instead of manually maintained.

***

## Test Results

| Metric              | Value                            |
| ------------------- | -------------------------------- |
| Focused tests       | 20 passed, 0 failed              |
| Full tests          | 3179 passed, 1 skipped, 0 failed |
| Package typecheck   | PASS                             |
| Workspace typecheck | PASS                             |
| Biome check         | PASS                             |
| Coverage            | Not collected                    |

***

## Lessons Learned

1. Enemy reducer inputs cross a trust boundary even when they look like ids; unsafe task and hero refs need the same privacy treatment as diagnostic strings.
2. Replay honesty is easier to preserve when each event family is classified as reconciliation, clear, or bounded accumulation before implementation.
3. Keeping `alertFocus` derived through one finalization path avoids priority drift as new Legion branches are added.

***

## Future Considerations

Items for future sessions:

1. Session 04 should bind camps and mission links without introducing a second game state authority.
2. Session 05 should use same-reference reducer no-ops to avoid unnecessary store persistence writes.
3. Session 06 should carry these privacy and replay constraints into browser-local persistence lifecycle behavior.
4. Session 07 should broaden regression coverage across replay, reconnect, mock, and snapshot traffic.

***

## Session Statistics

* **Tasks**: 20 completed
* **Files Created**: 7
* **Files Modified**: 6
* **Tests Added**: Focused reducer coverage expanded to 20 tests
* **Blockers**: 0 resolved


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