slate-ar-fast

# Slate AR Fast Handle $ARGUMENTS. Use this when the user says "make it fast", "fastest", "perf", or wants the agent to pick the highest-value Slate v2 performance target. This is an expert override. The normal broad workflow is `slate-ar-perfect <surface>`, which may call this internally. ## Contract Load `slate-ar-status` first. If $ARGUMENTS names a specific target or surface, run `slate-ar-perf` on that target. If the target is missing but specific, `slate-ar-perf` should create the benchmark target and correctness contract. If no target is named, pick the hottest target from current evidence: 1. user-visible behavior latency first; 2. regression versus legacy next; 3. broad architectural fanout next; 4. noisy raw microbenchmarks last. Bare `slate-ar-fast` means fastest-safe loop, not a one-off benchmark probe. Use `autogoal` unless the user explicitly says `probe`, `status`, or asks for a single read-only measurement. The goal should target one primary metric and one correctness contract. If no target is named, choose the hottest target and record why. ## No-Regression Rule Every kept perf packet needs correctness evidence. If selection, typing, copy, paste, undo, IME, focus, cursor placement, or follow-up input regresses, log the packet as `checks_failed` or route to `slate-patch`. If correctness coverage is missing, create or route to the missing oracle before optimizing. Do not make the metric faster by weakening behavior, delaying input, or hiding work behind debounce. ## Stop Rules Stop when one of these is true: - target threshold is met with checks green; - legacy parity is met where legacy is the comparison; - three correctness-green packets improve the primary metric by less than 5%; - the next safe win needs `slate-plan`; - behavior correctness blocks further perf work. ## Handoff Report target, benchmark command, primary metric, baseline/latest/best, checks, kept/discarded/checks-failed packets, and next target.