diagnose-runtime

diagnose-runtime is a skill for Claude Code, Codex from urmzd/dotfiles. It costs 171 tokens per session (1,738 once invoked), scanned B, original, Apache-2.0.

A method for finding the cause of runtime problems on your own computer, including crashes, errors, hangs, slowdowns, high resource use, and hardware or USB issues. Runtime problems happen while a program is running.

In plain words
What is it for?
Use it to investigate local processes and logs, narrow a failure with input or history checks, examine CPU or memory use, and diagnose serial or USB issues. It stops after a verified diagnosis and recommended fix.
Why use it?
It replaces guesswork with reproduction, isolation, logs or system tracing, a testable explanation, and verification that the problem is actually resolved.

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/urmzd/dotfiles/diagnose-runtime
Any agent
npx skills add urmzd/dotfiles --skill diagnose-runtime
Clone the repo
git clone --depth 1 https://github.com/urmzd/dotfiles

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 diagnose-runtime

README.md
[![agentmods](https://agentmods.dev/badge/skills/urmzd/dotfiles/diagnose-runtime.svg)](https://agentmods.dev/skills/urmzd/dotfiles/diagnose-runtime)
Your own site
<a href="https://agentmods.dev/skills/urmzd/dotfiles/diagnose-runtime"><img src="https://agentmods.dev/badge/skills/urmzd/dotfiles/diagnose-runtime.svg" alt="Measured on agentmods" height="20"></a>
Per session 171 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,738 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 $0.00171 $0.01738
Opus 5 $0.00086 $0.00869
Sonnet 5 $0.00034 $0.00348
Haiku 4.5 $0.00017 $0.00174

Measured 3d ago against content hash 0bc8849e0f95, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

diagnose-runtime scanned grade B with 1 finding 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 3d 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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

| Syscall-level mystery | `sudo dtruss -p <pid>` (macOS) / `strace -p <pid>` (Linux) | every syscall and where it blocks |
dot_agents/skills/diagnose-runtime/SKILL.md · 115 lines

How it starts

The opening of the file, as written. The whole thing — 115 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Diagnose Runtime

Triage a local runtime problem on this machine. The remote counterpart for red pipelines is [[diagnose-ci]]; once the cause is known and you want to apply and re-ship the fix, hand off to [[fix-and-retry]]. This skill stops at a verified diagnosis and a recommended fix.

Method

Work the loop in order. Skipping reproduction is the most common way a "fix" fails to hold.

  1. Reproduce. Get a deterministic trigger before changing anything. Capture the exact command, inputs, and environment. If it is intermittent, note the frequency (1-in-N) and any correlation (load, time, specific input file). An unreproducible bug cannot be verified fixed.
  2. Isolate. Shrink the surface until the failing component is unambiguous: bisect inputs (halve the data, the config, the call graph), bisect history (git bisect), and attach an observer (logs, a tracer, a sampler). Change one variable at a time.
  3. Hypothesize. State the suspected cause as a falsifiable sentence: "the process blocks on a fsync to a full disk", not "I/O is slow". A hypothesis you cannot test is a guess.
  4. Verify. Apply the smallest change that should fix the hypothesized cause, then re-run the reproduction. The bug must disappear when the change is in and return when it is reverted. If it does not, the hypothesis was wrong: go back to step 2 with what you learned.

Pick the tool by symptom

Symptom First reach for What it tells you
Crash / error / panic the error text + Console.app (or log show --last 10m) the actual exception, signal, and stack
Hang / deadlock / spinner sample <pid> 5 then spindump where every thread is stuck right now
High CPU / running hot ps -Ao pid,pcpu,comm -r | head -20 then Activity Monitor (Energy/CPU tab) which process is burning cycles
High memory / swap ps -Ao pid,rss,comm -m | head -20, Activity Monitor (Memory tab) the leaker; watch RSS climb over time
Slow operation sample during the slow window, or time <cmd> CPU-bound vs blocked-on-I/O
Stuck on a file / port lsof -p <pid>, lsof <path>, lsof -i :<port> open handles, who holds the lock/port
Disk / "no space" df -h, du -sh * full volume or inode exhaustion
Serial / USB / device ls /dev/tty.* /dev/cu.*, ioreg -p IOUSB, system_profiler SPUSBDataType whether the OS even sees the device
Syscall-level mystery sudo dtruss -p <pid> (macOS) / strace -p <pid> (Linux) every syscall and where it blocks

Read the full file on GitHub · 115 lines

Files

What ships with it

1 file 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. 3d ago First seen · 115 lines · 171 tokens per session scan B 0bc8849e0f95

Subscribe to this mod's changes

diagnose-runtime is a skill published in the GitHub repository urmzd/dotfiles (3 stars, last pushed 22d ago), licensed Apache-2.0. It adds 171 tokens to every session and 1,738 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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