API Drift Perf Execution Batch

Goal

Finish the kept API-drift performance program until every drift class is either:

• benchmarked and green enough
• benchmarked and explicitly diagnostic
• or benchmarked and consciously deferred with a reason

Hard Rules

• do not expand the drift inventory unless a kept public surface is missing
• treat slate-batch-engine as compare-only black-box evidence
• blocker lanes outrank diagnostic lanes
• generic tax beats one-off cleanup
• non-API drift stays out unless needed to explain blocker-facing numbers

Phases

• Phase 0: Grounding
  • context snapshot
  • Ralph state
  • frozen drift register exists
• Phase 1: Freeze inventory and register truth
  • verify all kept drift classes are represented
  • stop inventory expansion
• Phase 2: Add missing drift lanes
  • wrapper-heavy richtext lane
  • normalization-mapped richtext lane
  • query/ref observation lane
  • node-transform hot-wrapper lanes
• Phase 3: Run lanes and capture current numbers
  • fill register
  • update scoreboard with blocker vs diagnostic split
• Phase 4: Cause analysis on red blocker-facing lanes
  • init vs live
  • wrapper vs core
  • pure value transform vs editor-operation path
  • observe/read vs mutate/write
• Phase 5: Rank fixes by leverage
  • generic tax first
  • surviving drift-specific hotspot second
• Phase 6: Start optimization only after the above is true

Working Notes

• richtext runtime dissection already exists and first read points at mark rendering, not toolbar subscription
• missing requested file: docs/shared/agent-tiers.md
• one explorer lane is running for wrapper-heavy richtext mapping
• fresh same-turn replacement reruns are noisier than the older frozen scoreboard implied; read them as bands, not scripture
• current red reads:
  • richtext blocker still slower than legacy
  • normalization compare still very red but diagnostic
  • query/ref only shows obvious pressure on rangeRef rebasing
• current green or near-green reads:
  • markdown
  • table
  • node-transform wrappers
  • editable-void is now basically parity
• scoped deslop review found no high-signal cleanup worth landing: extracting shared benchmark helpers across the new scripts would be needless abstraction right now