# 2025-12-06 P2 Implementation Summary

**Date:** 2025-12-06
**Status:** ✅ P2 Complete
**Objective:** Enhance Security and Documentation

## Executive Summary
This session focused on completing Priority 2 (P2) tasks for the Backend v1.4.3. All P2 objectives were met, including API documentation, secure session management, observability, and API hardening.

**Note:** While P2 features are complete and verified by code review, the `pnpm build` process is currently failing due to pre-existing issues in P0 modules (Casl Ability & Workflow DSL) that were outside the scope of this session. These build errors must be addressed in the next session (P0 Urgent).

## Completed Tasks

### ✅ P2-1: Swagger API Documentation
- **Objective:** Improve API discoverability.
- **Changes:**
  - Configured `SwaggerModule` at `/docs`.
  - Added full documentation for `AuthController`, `CorrespondenceController`, `RfaController`, and `UserController`.
  - Decorated DTOs with `@ApiProperty` for schema clarity.

### ✅ P2-2: Refresh Token Mechanism
- **Objective:** Secure session management implementation (ADR-016).
- **Changes:**
  - Created `RefreshToken` entity (hashed tokens).
  - Implemented `AuthService` logic for:
    - **Token Generation:** Access (15m) + Refresh (7d).
    - **Storage:** Hashed in DB.
    - **Rotation:** Refresh token reuse triggers rotation.
    - **Revocation:** Security mechanism to invalidate stolen token families.
  - Exposed `POST /auth/refresh` endpoint.

### ✅ P2-3: Prometheus Metrics
- **Objective:** System observability.
- **Changes:**
  - Integrated `@willsoto/nestjs-prometheus` and opened `/metrics`.
  - Implemented standard metrics (CPU, Memory).
  - Added custom HTTP metrics (`http_requests_total`, `http_request_duration_seconds`) via `PerformanceInterceptor`.
  - Refactored `MonitoringModule` for modularity.

### ✅ P2-4: Rate Limiting & Security Headers
- **Objective:** API Hardening.
- **Changes:**
  - **Throttler:** Verified global rate limit (100/min) and strict login limit (5/min).
  - **Helmet:** Configured Security Headers with custom CSP to support Swagger UI.
  - **CORS:** Dynamic configuration connected to `ConfigService`.

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## Known Issues (P0 - Urgent)

The following build errors were identified but deferred as they belong to P0 scope:

1.  **AbilityFactory (CASL):** TypeScript mismatch in Permission loops (`CASL integration`).
2.  **WorkflowEngine (DSL):** TypeScript mismatch in Zod Schema validation (`WorkflowParser`).

**Action Plan:** These must be fixed immediately in the next session to restore build stability.

## Artifacts Created
- `specs/09-history/2025-12-06_p2-completion.md` (This file)
- `src/common/auth/entities/refresh-token.entity.ts`
- `src/modules/monitoring/` (Refactored)
