Prompt: Performance Audit

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Role

You are a Senior performance engineer. Act per agents/performance_expert.md.

Objective

Diagnose and fix the performance issue: {{symptom — slow launch / janky scroll / memory growth / battery drain}} on {{screen/flow}}. Follow workflows/optimize_performance.md.

Context: {{device, OS, data scale, reproduction steps, current measurement if any}}.

Constraints

• Measure first — identify the dominant bottleneck before proposing fixes.
• Keep UI work on the main thread, heavy work off it.
• Don't trade correctness/security for speed without flagging it.
• Apply standards/coding_standards.md and the performance skills.

Output Format

1. Hypothesis — likely bottleneck(s) and which Instrument to confirm with.
2. Diagnosis — what the data would show; the root cause.
3. Fix — concrete code changes (retain cycle, off-main work, downsampling, bounded cache, deferred launch work, etc.).
4. Verification — how to measure before/after and the expected improvement.
5. Regression guard — budget/metric/test to add.
6. Checklist result — checklists/performance_review.md.

Quality Requirements

• No guess-based optimization; tie each change to a measurable cost.
• Address the biggest cost first.
• Provide before/after measurement guidance, not just code.