perf-profile

perf-profile is a skill for Claude Code, Codex from OutlineDriven/odin-codex-plugin. It costs 0 tokens per session (1,077 once invoked), scanned A, original, Apache-2.0.

A performance investigation guide for finding which parts of a program use the most time or memory, using measurements such as flame graphs, allocation tracking, and latency profiles.

In plain words
What is it for?
Use it to locate performance bottlenecks, compare cold-start and steady-state costs, investigate slow requests or memory growth, and verify that an optimization really helped.
Why use it?
It replaces guesswork with evidence when an application misses its speed, throughput, or memory target, or when a benchmark gets worse.

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/outlinedriven/odin-codex-plugin/perf-profile
Any agent
npx skills add OutlineDriven/odin-codex-plugin --skill perf-profile
Clone the repo
git clone --depth 1 https://github.com/OutlineDriven/odin-codex-plugin

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 perf-profile

README.md
[![agentmods](https://agentmods.dev/badge/skills/outlinedriven/odin-codex-plugin/perf-profile.svg)](https://agentmods.dev/skills/outlinedriven/odin-codex-plugin/perf-profile)
Your own site
<a href="https://agentmods.dev/skills/outlinedriven/odin-codex-plugin/perf-profile"><img src="https://agentmods.dev/badge/skills/outlinedriven/odin-codex-plugin/perf-profile.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,077 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 $0.00000 $0.01077
Opus 5 $0.00000 $0.00539
Sonnet 5 $0.00000 $0.00215
Haiku 4.5 $0.00000 $0.00108

Measured 5d ago against content hash c3b66bcdd461, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

perf-profile 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 5d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

skills/perf-profile/SKILL.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Performance is a contract with reality. Intuition about hot paths is wrong more often than right. Capture, locate, hypothesize, optimize, re-measure, prove the regression with a benchmark — then defend the win with an invariant.

When to Apply / NOT

Apply: latency or throughput SLO violation; memory pressure (RSS growth, GC churn); benchmark regression; pre-optimization scoping; cold-start vs steady-state cost split; cache locality / branch-prediction concerns.

NOT apply: defect with wrong outputs; architectural redesign; micro-optimization without budget pressure; untested code (write tests first).

Anti-patterns

  • Optimize without profile: intuition-driven changes.
  • Single-run benchmarks: variance dominates. Use hyperfine --warmup 3 --min-runs 10.
  • Profile in debug build: optimizer-disabled binaries lie.
  • Confuse flat profile with call-graph: self-time vs total-time tell different stories.
  • Ignoring tail latency: p50 stays flat while p99 explodes.
  • Cherry-picking the win: re-measure end-to-end.
  • Allocation blind spot: CPU profiler hides GC.
  • Forgetting the regression guard.

Workflow (language-neutral)

  1. Define budget — restate target metric: latency p95 < X ms, throughput > Y rps, RSS < Z MB.
  2. Establish baseline — run unoptimized workload under hyperfine plus profiler. Save raw artifacts.
  3. Capture profile — sampled CPU profile → flamegraph; allocation profile if memory-bound; latency histogram for tail.
  4. Locate hotspot — top self-time function or widest plateau. Cross-check with allocation profile.
  5. Hypothesize — one falsifiable claim with predicted delta.
  6. Optimize minimally — smallest change targeting the hypothesis.
  7. Re-profile — capture same metric; differential flamegraph.
  8. Prove the winhyperfine 'baseline' 'optimized' --warmup 3 --min-runs 10.
  9. Guard the win — add CI benchmark with regression bound.

Reading Flamegraphs

  • Wide plateau on top: hot self-time function — primary target.
  • Narrow towers: deep call chains — examine for over-abstraction.
  • Repeated motifs: same callee under many parents — candidate for inlining or caching.
  • Missing frames: rebuild with -fno-omit-frame-pointer / RUSTFLAGS=-C force-frame-pointers=yes.
  • Differential flamegraph (hotspot --diff): red = added cost, blue = removed.

Read the full file on GitHub · 66 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. 5d ago First seen · 66 lines · 0 tokens per session scan A c3b66bcdd461

Subscribe to this mod's changes

perf-profile is a skill published in the GitHub repository OutlineDriven/odin-codex-plugin (15 stars, last pushed 1mo ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 1,077 tokens. 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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