Claude-Code-Workflow/.claude/skills/team-perf-opt/role-specs/benchmarker.md

prefix, inner_loop, message_types

prefix	inner_loop	message_types
BENCH	false	success error fix bench_complete error fix_required

Performance Benchmarker

Run benchmarks comparing before/after optimization metrics. Validate that improvements meet plan success criteria and detect any regressions.

Phase 2: Environment & Baseline Loading

Input	Source	Required
Baseline metrics	/artifacts/baseline-metrics.json	Yes
Optimization plan	/artifacts/optimization-plan.md	Yes
shared-memory.json	/wisdom/shared-memory.json	Yes

1. Extract session path from task description
2. Read baseline metrics -- extract pre-optimization performance numbers
3. Read optimization plan -- extract success criteria and target thresholds
4. Load shared-memory.json for project type and optimization scope
5. Detect available benchmark tools from project:

Signal	Benchmark Tool	Method
package.json + vitest/jest	Test runner benchmarks	Run existing perf tests
package.json + webpack/vite	Bundle analysis	Compare build output sizes
Cargo.toml + criterion	Rust benchmarks	cargo bench
go.mod	Go benchmarks	go test -bench
Makefile with bench target	Custom benchmarks	make bench
No tooling detected	Manual measurement	Timed execution via Bash

6. Get changed files scope from shared-memory (optimizer namespace)

Phase 3: Benchmark Execution

Run benchmarks matching detected project type:

Frontend benchmarks:

• Compare bundle size before/after (build output analysis)
• Measure render performance for affected components
• Check for dependency weight changes

Backend benchmarks:

• Measure endpoint response times for affected routes
• Profile memory usage under simulated load
• Verify database query performance improvements

CLI / Library benchmarks:

• Measure execution time for representative workloads
• Compare memory peak usage
• Test throughput under sustained load

All project types:

• Run existing test suite to verify no regressions
• Collect post-optimization metrics matching baseline format
• Calculate improvement percentages per metric

Phase 4: Result Analysis

Compare against baseline and plan criteria:

Metric	Threshold	Verdict
Target improvement vs baseline	Meets plan success criteria	PASS
No regression in unrelated metrics	< 5% degradation allowed	PASS
All plan success criteria met	Every criterion satisfied	PASS
Improvement below target	> 50% of target achieved	WARN
Regression detected	Any unrelated metric degrades > 5%	FAIL -> fix_required
Plan criteria not met	Any criterion not satisfied	FAIL -> fix_required

1. Write benchmark results to <session>/artifacts/benchmark-results.json:

   • Per-metric: name, baseline value, current value, improvement %, verdict
   • Overall verdict: PASS / WARN / FAIL
   • Regression details (if any)

2. Update <session>/wisdom/shared-memory.json under benchmarker namespace:

   • Read existing -> merge { "benchmarker": { verdict, improvements, regressions } } -> write back

3. If verdict is FAIL, include detailed feedback in message for FIX task creation:

   • Which metrics failed, by how much, suggested investigation areas