# Sprint 67 Plan: Refactoring-Aware Transpilation and Round-Trip Stability

## Context

Teams will refactor after transpilation. Sprint 67 ensures round-trip stability and
controlled drift when code evolves post-port.

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## Goals

1. Track semantic drift after manual refactors
2. Enable safe re-projection from changed targets
3. Detect round-trip instability early
4. Preserve migration traceability across iterations

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## Steps

### Step 899: Semantic drift detector between revisions (12 tests)
### Step 900: Round-trip stability checker (source->target->source/IR) (10 tests)
### Step 901: Drift severity classifier (10 tests)
### Step 902: Refactor intent annotation model (10 tests)
### Step 903: Reprojection safety policy (10 tests)
### Step 904: Traceability chain generator (origin->current) (8 tests)
### Step 905: `whetstone_check_semantic_drift` MCP tool (8 tests)
### Step 906: `whetstone_generate_reprojection_plan` MCP tool (8 tests)
### Step 907: Drift audit report artifact (8 tests)
### Step 908: Sprint 67 integration summary + regression (8 tests)

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## Stability Rule

- High-severity drift blocks automatic re-projection.