# Sprint 63 Plan: Learned Adapter Hints (Non-Authoritative)

## Context

The system can learn from historical review outcomes, but learned behavior must
remain bounded by deterministic policy and explicit governance.

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## Goals

1. Introduce learned suggestion layer for adapter decisions
2. Keep learned hints non-authoritative by default
3. Measure whether hints reduce review load and divergence rates
4. Add rollback controls for bad hint generations

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## Steps

### Step 859: Hint feature extraction from decision ledgers (12 tests)
### Step 860: Pair-specific hint model interface (10 tests)
### Step 861: Deterministic fallback contract when hints unavailable (10 tests)
### Step 862: Hint confidence + uncertainty packet format (10 tests)
### Step 863: A/B harness for hint effectiveness (10 tests)
### Step 864: Hint rollback and suppression controls (8 tests)
### Step 865: `whetstone_get_adapter_hints` MCP tool (8 tests)
### Step 866: `whetstone_set_hint_policy` MCP tool (8 tests)
### Step 867: Hint safety guardrails and audit fields (8 tests)
### Step 868: Sprint 63 integration summary + regression (8 tests)

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## Governance Rule

- Learned hints may suggest; deterministic policy decides.