performance-optimization

A performance-optimization guide is a measurement-led process for finding and reducing slowdowns in software, including APIs, interfaces, memory use, builds, and database queries.

In plain words
What is it for?
Use it to profile bottlenecks, establish baseline timings, rank improvements, apply one change at a time, and add monitoring or CI checks.
Why use it?
It prevents time being wasted on guesses by requiring profiling and benchmarks before changes, followed by verification and regression checks.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/jeremydev87/codingbuddy/performance-optimization
Any agent
npx skills add JeremyDev87/codingbuddy --skill performance-optimization
Clone the repo
git clone --depth 1 https://github.com/JeremyDev87/codingbuddy

Made for: Claude Code, Codex.

Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 717 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00021 $0.00717
Opus 5 $0.00010 $0.00358
Sonnet 5 $0.00004 $0.00143
Haiku 4.5 $0.00002 $0.00072

Measured 2d ago against content hash 041482bcded6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

performance-optimization scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

packages/rules/.ai-rules/skills/performance-optimization/SKILL.md · 80 lines

How it starts

The opening of the file, as written. The whole thing — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Performance Optimization

Iron Law: NO OPTIMIZATION WITHOUT PROFILING FIRST

No exceptions - not for "obvious" bottlenecks, "quick wins", or "best practices".

Use for: Slow APIs, UI lag, high memory, slow builds, database queries, any "make it faster" request.

Five Phases

Phase Activity Output
1. Profile Find hot paths with profiler Bottlenecks with % of time
2. Benchmark 5 warm-up + 10 measured runs Baseline with mean, std, p95
3. Prioritize Apply Amdahl's Law ROI-ranked list
4. Optimize ONE change, verify Measured improvement
5. Prevent CI gates, monitoring Regression detection

Phase 1: Profile

  1. Clarify metrics ("It's slow" → p50? p95?)
  2. Select profiler:
    • CPU: perf, py-spy, node --prof, Chrome DevTools
    • Memory: heaptrack, memray, Chrome Memory
    • I/O: strace, iostat, slow query log
    • Distributed: OpenTelemetry, Jaeger, Datadog
    • Serverless: AWS X-Ray, CloudWatch
    • Mobile: Android Profiler, Xcode Instruments
  3. Profile cold AND warm cache
  4. Flame graphs: Wider bars = more time
  5. Time-box: Max 2 hours → Escalate if unclear

Phase 3: Prioritize (Amdahl's Law)

Formula: Speedup = 1 / ((1 - P) + P/S)

Bottleneck % Max Speedup Action
< 5% < 1.05x Skip
5-20% 1.05-1.25x Low priority
20-50% 1.25-2x Medium
> 50% > 2x High priority

Multiple similar %? Optimize easiest first. Re-profile after each.

Phase 4: Optimize

  1. Write benchmark test first
  2. ONE change at a time
  3. Compare statistically
  4. Rollback: Separate commit, feature flags

Phase 5: Prevent

Add CI gate: PERF_BUDGET_MS: 150 → fail build if exceeded

Red Flags - STOP

  • "I know where the bottleneck is" → Profile first
  • "Let's just add caching" → Measure first
  • "One run is enough" → High variance
  • "The fix is obvious" → Return to Phase 1

Read the full file on GitHub · 80 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 80 lines · 21 tokens per session scan A 041482bcded6

Subscribe to this mod's changes

performance-optimization is a skill published in the GitHub repository JeremyDev87/codingbuddy (31 stars, last pushed 4mo ago), licensed MIT. It adds 21 tokens to every session and 717 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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