# Phase 5: State Accumulator

**Purpose:** Append-only event log that tracks every iteration of every loop.
**TS Module:** `src/tier2-primitives/loops/state-accumulator.ts`

## What It Does

- Records every iteration with full phase output and metrics
- Aggregates roll-ups: avg duration, quality, success rate, improvement delta
- Tracks trends: improving, stable, or degrading across iterations
- Produces point-in-time snapshots

## Data Shape

Each iteration records: number, phase, plan, executed, observation, reflection, refinement, metrics (durationMs, successRate, qualityScore, improvementDelta), timestamp.

## Key Rules

- The accumulator is the loop's memory — without it, dreaming has no data
- Take a snapshot before dreaming (pins the state at dream time)
- Load from store when resuming a session