# Phase 6: Convergence Check

**Purpose:** The loop doesn't run forever. It runs until it converges.
**TS Module:** `src/tier2-primitives/loops/convergence-check.ts`

## What It Does

Detects when to stop the loop:

1. **Max iterations** reached → hard stop
2. **Diminishing returns** → improvement delta below threshold for N iterations
3. **Quality plateau** → quality score flat for N iterations and already acceptable
4. **Target achieved** → quality and success rate both above 0.95

## Signals

| Signal | Meaning | Action |
|--------|---------|--------|
| `continuing` | Loop should keep running | Let it run |
| `diminishing_returns` | Delta below threshold | Exit — more iterations won't help |
| `quality_plateau` | Quality flat and acceptable | Exit with current state |
| `target_achieved` | Quality > 0.95 and success > 0.95 | Exit — goal fully met |

## Key Rules

- Set `convergenceThreshold` based on task difficulty (0.05 for standard, 0.02 for precise)
- In the rubric engine, convergence is replaced by rubric-guided exit conditions
- A plateau with low quality signals "restart approach" — not "exit successful"