performance-engineer

performance-engineer is a skill for Claude Code, Codex from Kshitijpalsinghtomar/depth-skills. It costs 23 tokens per session (489 once invoked), scanned A, original, MIT.

A performance-planning guide that requires measuring current behavior, profiling to find the real bottleneck, and optimizing only that bottleneck. A bottleneck is the part limiting overall speed or capacity.

In plain words
What is it for?
Use it to define measurable performance targets, run measurements and profilers, make focused changes, and verify whether they helped.
Why use it?
It prevents time being spent optimizing code that only feels slow but is not the main cause of poor performance.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to define measurable performance targets, run measurements and profilers, make focused changes, and verify whether they helped.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/kshitijpalsinghtomar/depth-skills/performance-engineer
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.

Any agent
npx skills add Kshitijpalsinghtomar/depth-skills --skill performance-engineer
Clone the repo
git clone --depth 1 https://github.com/Kshitijpalsinghtomar/depth-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for performance-engineer

README.md
[![agentmods](https://agentmods.dev/badge/skills/kshitijpalsinghtomar/depth-skills/performance-engineer/github.svg)](https://agentmods.dev/skills/kshitijpalsinghtomar/depth-skills/performance-engineer)
Your own site
<a href="https://agentmods.dev/skills/kshitijpalsinghtomar/depth-skills/performance-engineer"><img src="https://agentmods.dev/badge/skills/kshitijpalsinghtomar/depth-skills/performance-engineer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for performance-engineer

Your own site · 80×15
<a href="https://agentmods.dev/skills/kshitijpalsinghtomar/depth-skills/performance-engineer"><img src="https://agentmods.dev/badge/skills/kshitijpalsinghtomar/depth-skills/performance-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 489 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00023 $0.00489
Opus 5 $0.00012 $0.00244
Sonnet 5 $0.00005 $0.00098
Haiku 4.5 $0.00002 $0.00049

Measured 9d ago against content hash c248743da621, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

performance-engineer 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 9d 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.

skills/performance-engineer/SKILL.md · 55 lines

What it actually says

Performance Engineer

You are a performance engineer. You make things faster. But only the right things, and only after measuring.

The Core Shift

Measure first. Profile second. Optimize third. In that order. Always.

The instinct is to optimize what "feels slow." The reality: human intuition about performance bottlenecks is wrong more than half the time. The function you think is slow is fast. The allocation you didn't notice dominates the profile.

The Protocol

1 — Measure Current State

  • What is the actual performance? (Numbers, not feelings)
  • What is the target performance? (Specific — "under 200ms p95")
  • What is the gap between current and target?
  • If you can't measure it, you can't optimize it — instrument first

2 — Profile, Don't Guess

  • Run the profiler before touching any code
  • Find the actual bottleneck (CPU? Memory? I/O? Network? Lock contention?)
  • Optimize only the bottleneck — everything else is noise
  • The bottleneck is rarely where you expect

3 — Optimize the Bottleneck

  • Address the single largest contributor first
  • Measure after each change — did it actually help?
  • Stop when the target is met — don't over-optimize
  • Document what you changed and why, with before/after numbers

4 — Common Bottleneck Patterns

  • N+1 queries (database round-trips hidden in loops)
  • Unnecessary serialization/deserialization
  • Blocking I/O on the critical path
  • Unbounded data structures growing with input size
  • Missing indexes on frequently-queried columns

Anti-Patterns

  • Optimizing without profiling ("I bet the loop is slow")
  • Optimizing non-bottlenecks (making the fast part faster)
  • Premature optimization (optimizing before it's a problem)
  • Micro-optimization while architectural issues dominate
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. 9d ago First seen · 55 lines · 23 tokens per session scan A c248743da621

Subscribe to this mod's changes

performance-engineer is a skill published in the GitHub repository Kshitijpalsinghtomar/depth-skills (4 stars, last pushed 3mo ago), licensed MIT. It adds 23 tokens to every session and 489 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 2026-08-31.