native-app-performance

native-app-performance is a skill for Claude Code, Codex from steipete/agent-scripts. It costs 20 tokens per session (502 once invoked), scanned A, original, MIT.

A command-line workflow for measuring native app performance with Apple’s xctrace tools, extracting timing samples, and ranking code hotspots.

In plain words
What is it for?
Recording performance traces, analyzing time samples, symbolizing stack traces, and finding the busiest parts of a native app.
Why use it?
It shows where an app spends time during a slow operation without requiring the graphical Instruments app.

Skill for Claude CodeCodex

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

Good fit Recording performance traces, analyzing time samples, symbolizing stack traces, and finding the busiest parts of a native app.

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Install with agentmods
npx agentmods add skills/steipete/agent-scripts/native-app-performance
About the project

Agent Scripts is a repository of shared instructions, reusable skills, helper scripts, and local safeguards for coding-agent workflows across multiple workspaces. It is for maintaining common agent behavior and portable development utilities between repositories.

steipete/agent-scripts · 7,379 stars · on GitHub · steipete.me

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 steipete/agent-scripts --skill native-app-performance
Clone the repo
git clone --depth 1 https://github.com/steipete/agent-scripts

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 native-app-performance

README.md
[![agentmods](https://agentmods.dev/badge/skills/steipete/agent-scripts/native-app-performance/github.svg)](https://agentmods.dev/skills/steipete/agent-scripts/native-app-performance)
Your own site
<a href="https://agentmods.dev/skills/steipete/agent-scripts/native-app-performance"><img src="https://agentmods.dev/badge/skills/steipete/agent-scripts/native-app-performance/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 native-app-performance

Your own site · 80×15
<a href="https://agentmods.dev/skills/steipete/agent-scripts/native-app-performance"><img src="https://agentmods.dev/badge/skills/steipete/agent-scripts/native-app-performance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 20 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 502 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00020 $0.00502
Opus 5.5 $0.00008 $0.00201
Sonnet 5.5 $0.00004 $0.00100
Haiku 4.5 $0.00002 $0.00050

Measured 1mo ago against content hash 0c8a67d976b2, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

native-app-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 1mo ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/extract_time_samples.py, scripts/record_time_profiler.sh, scripts/top_hotspots.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/native-app-performance/SKILL.md · 64 lines

What it actually says

Native App Performance (CLI-only)

Goal: record Time Profiler via xctrace, extract samples, symbolicate, and propose hotspots without opening Instruments.

Quick start (CLI)

  1. Record Time Profiler (attach):
# Start app yourself, then attach
xcrun xctrace record --template 'Time Profiler' --time-limit 90s --output /tmp/App.trace --attach <pid>
  1. Record Time Profiler (launch):
xcrun xctrace record --template 'Time Profiler' --time-limit 90s --output /tmp/App.trace --launch -- /path/App.app/Contents/MacOS/App
  1. Extract time samples:
scripts/extract_time_samples.py --trace /tmp/App.trace --output /tmp/time-sample.xml
  1. Get load address for symbolication:
# While app is running
vmmap <pid> | rg -m1 "__TEXT" -n
  1. Symbolicate + rank hotspots:
scripts/top_hotspots.py --samples /tmp/time-sample.xml \
  --binary /path/App.app/Contents/MacOS/App \
  --load-address 0x100000000 --top 30

Workflow notes

  • Always confirm you’re profiling the correct binary (local build vs /Applications). Prefer direct binary path for --launch.
  • Ensure you trigger the slow path during capture (menu open/close, refresh, etc.).
  • If stacks are empty, capture longer or avoid idle sections.
  • xcrun xctrace help record and xcrun xctrace help export show correct flags.

Included scripts

  • scripts/record_time_profiler.sh: record via attach or launch.
  • scripts/extract_time_samples.py: export time-sample XML from a trace.
  • scripts/top_hotspots.py: symbolicate and rank top app frames.

Gotchas

  • ASLR means you must use the runtime __TEXT load address from vmmap.
  • If using a new build, update the --binary path; symbols must match the trace.
  • CLI-only flow: no need to open Instruments if stacks are symbolicated via atos.
Files

What ships with it

3 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. 1mo ago First seen · 64 lines · 20 tokens per session scan A 0c8a67d976b2

Subscribe to this mod's changes

native-app-performance is a skill published in the GitHub repository steipete/agent-scripts (7,379 stars, last pushed yesterday), licensed MIT. It adds 20 tokens to every session and 502 once invoked, about $0.0001 per session on Opus 5.5. 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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