# Sprint 129 Plan: Debug Constraints, Budgets, and Recovery Advice

## Context

Sprint 128 added deterministic recipes and traces. Sprint 129 adds policy constraints,
budget estimation, and recovery advice to make step-by-step debugging safer for
small agents operating with strict limits.

---

## Goals

1. Add deterministic constraint and budget models
2. Add deterministic recovery and stop-reason models
3. Add MCP tools to retrieve constraints, budgets, recovery, and stop reasons
4. Keep outputs machine-readable and deterministic

---

## Steps

### Step 1529: Debug policy constraint model (10 tests)
### Step 1530: Debug action budget model (10 tests)
### Step 1531: Debug recovery advisor model (8 tests)
### Step 1532: Debug stop-reason classifier model (8 tests)
### Step 1533: `whetstone_get_debug_constraints` MCP tool (8 tests)
### Step 1534: `whetstone_estimate_debug_budget` MCP tool (8 tests)
### Step 1535: `whetstone_get_recovery_advice` MCP tool (8 tests)
### Step 1536: `whetstone_classify_debug_stop_reason` MCP tool (8 tests)
### Step 1537: Debug guidance packet model (8 tests)
### Step 1538: Sprint 129 integration summary + regression (8 tests)

---

## Architecture Gate

- Constraint outputs must be deterministic by mode
- Budget outputs must be deterministic for equal inputs
- Recovery and stop-reason packets must be explicit and machine-readable
- Max 600 lines per header