# Sprint 142 Plan: Text-to-AST Incremental Synchronization for C++

## Context

Hybrid mode needs fast text editing without losing AST consistency. Sprint 142
adds deterministic incremental text->AST synchronization with C++ priority.

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## Goals

1. Convert C++ text edits into incremental AST updates
2. Preserve node identity/stability where possible
3. Emit structured sync diagnostics when mapping is ambiguous
4. Keep sync deterministic for identical edit streams

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## Steps

### Step 1659: Incremental text edit packet schema (10 tests)
### Step 1660: C++ text-delta parser bridge model (10 tests)
### Step 1661: Node identity preservation policy model (10 tests)
### Step 1662: Incremental sync diagnostics model (10 tests)
### Step 1663: `whetstone_sync_text_to_ast` MCP tool (8 tests)
### Step 1664: `whetstone_get_sync_diagnostics` MCP tool (8 tests)
### Step 1665: `whetstone_get_sync_identity_report` MCP tool (8 tests)
### Step 1666: Sync confidence score model (8 tests)
### Step 1667: Incremental sync report artifact (8 tests)
### Step 1668: Sprint 142 integration summary + regression (8 tests)

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## Architecture Gate

- Incremental sync must be deterministic for identical text deltas
- Identity preservation rules must be explicit and auditable
- Ambiguous mappings must produce structured diagnostics
- Max 600 lines per header