performance

A method for improving software speed or size by measuring a starting point, making one change, and measuring again.

In plain words
What is it for?
Use it when investigating slow pages, delayed interactions, long-running jobs, large bundles, or other performance concerns.
Why use it?
It helps separate real improvements from guesses and prevents keeping code changes that add complexity without measurable benefit.

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/prabhdeepsingh/claude-plugins/performance
Any agent
npx skills add PrabhdeepSingh/claude-plugins --skill performance
Clone the repo
git clone --depth 1 https://github.com/PrabhdeepSingh/claude-plugins

Made for: Claude Code, Codex.

Per session 99 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,486 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 $0.00099 $0.01486
Opus 5 $0.00049 $0.00743
Sonnet 5 $0.00020 $0.00297
Haiku 4.5 $0.00010 $0.00149

Measured 2d ago against content hash 8a6469143afc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

performance 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.

sonu/skills/performance/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 — the measurement is the work

Most "optimizations" are guesses wearing confidence: a change lands because it should be faster, nobody measures, and the codebase accretes complexity that never bought anything. The discipline that prevents this is not knowing the tricks — it's the loop around them: measure a baseline, change one thing, re-measure the same way, and keep only what provably paid. Code you keep, you maintain forever; make it pay for itself.

How to apply this

Run the loop in order: baseline → identify the bottleneck → one change → verify against the baseline → keep or revert → record the attempt. When invoked directly as /sonu:performance, apply it to $ARGUMENTS — the text typed after the invocation; if that token appears literally or is empty, apply it to the performance concern in the current discussion.


1. Baseline before touching anything

No baseline, no optimization — without a starting number, "faster" is a feeling. Capture the metric that matters to the user (page-load milestones, interaction latency, API p95, job duration, bundle bytes — whatever the complaint names), under stated conditions (dataset size, cache state, hardware/environment), with a fixed budget (sample count, wall-clock, or request count). Write the number down; the verdict in §4 is computed against it.

Profile, don't deduce. The bottleneck is where the time measured goes, not where the code looks slow — profilers, query plans, and waterfall traces exist because intuition about hot paths is reliably wrong. Route by symptom first: slow first render → network and render path; slow interaction → main-thread work; slow API → the server and its queries; then profile inside that region.

2. One change at a time

Land one optimization per measurement cycle. Three optimizations measured together produce one number that can't be attributed — if the total improved, you may be keeping two regressions paid for by one win ([[debugging]]'s one-change rule, applied to speed). Small, separately-verified changes also revert cleanly when §4 says revert.

Read the full file on GitHub · 80 lines

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 · 99 tokens per session scan A 8a6469143afc

Subscribe to this mod's changes

performance is a skill published in the GitHub repository PrabhdeepSingh/claude-plugins (3 stars, last pushed 2d ago), licensed MIT. It adds 99 tokens to every session and 1,486 once invoked, about $0.0005 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 2026-08-31.

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