# Sprint 155 Plan: Multi-Language GA Gate and Tiered Rollout

## Context

Sprint 155 defines final release governance for constructive editing with
language-tiered readiness (`ga`, `beta`, `experimental`) and controlled rollout.

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## Goals

1. Define GA criteria and blocking gates per language tier
2. Add policy controls for staged enablement and rollback by tier
3. Publish release certification packets with determinism/reliability evidence
4. Enable safe rollout where some languages are GA while others are not

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## Steps

### Step 1789: Multi-language GA criteria schema (10 tests)
### Step 1790: Language tier policy model (`ga`, `beta`, `experimental`) (10 tests)
### Step 1791: Tiered rollout and rollback control model (10 tests)
### Step 1792: Cross-language release evidence aggregator model (10 tests)
### Step 1793: `whetstone_run_constructive_ga_gate` MCP tool (8 tests)
### Step 1794: `whetstone_get_constructive_rollout_status` MCP tool (8 tests)
### Step 1795: `whetstone_set_language_rollout_tier` MCP tool (8 tests)
### Step 1796: Constructive release certification packet model (8 tests)
### Step 1797: Constructive GA publication bundle (8 tests)
### Step 1798: Sprint 155 integration summary + full-program regression (8 tests)

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## Architecture Gate

- GA decisions must be evidence-backed, deterministic, and policy-driven
- Tier transitions must be explicit, reversible, and auditable
- Non-GA language tiers must not block GA rollout for ready languages
- Max 600 lines per header