sysadmin-performance

A skill for diagnosing and tuning slow Debian or Ubuntu Linux computers by measuring CPU, memory, storage, network, and running processes.

In plain words
What is it for?
Use it to investigate slow machines, identify the cause, apply targeted system changes, and compare measurements before and after.
Why use it?
It finds the actual resource bottleneck before suggesting changes, reducing the risk of tuning the wrong part of the system.

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/hermeticormus/linux-sysadmin-skills/sysadmin-performance
Any agent
npx skills add HermeticOrmus/linux-sysadmin-skills --skill sysadmin-performance
Clone the repo
git clone --depth 1 https://github.com/HermeticOrmus/linux-sysadmin-skills

Made for: Claude Code, Codex.

Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 620 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 $0.00056 $0.00620
Opus 5 $0.00028 $0.00310
Sonnet 5 $0.00011 $0.00124
Haiku 4.5 $0.00006 $0.00062

Measured 2d ago against content hash 342cab63ef1f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sysadmin-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.

skills/sysadmin-performance/SKILL.md · 95 lines

How it starts

The opening of the file, as written. The whole thing — 95 lines — stays where its author put it; the contents beside it link to each section on GitHub.

System performance analysis

Analyze and optimize performance on a Debian/Ubuntu Linux machine. Measure before forming an opinion; tune the bottleneck, not a guess. Confirm before any change that alters kernel parameters, kills processes, or disables services.

Performance analysis steps

1. Current-state assessment

CPU:

top -bn1 | head -20
mpstat 1 5

Look at usage patterns, per-process CPU, and load average.

Memory:

free -h
vmstat 1 5

Look at RAM usage, swap usage, and memory pressure.

Disk:

df -h
iostat -x 1 5

Look at free space, I/O performance, and per-disk utilization.

Network:

ifstat 1 5
netstat -s

Look at throughput, packet statistics, and errors or drops.

Processes:

ps aux --sort=-%mem | head -10
ps aux --sort=-%cpu | head -10

Look for resource hogs, zombie processes, and process states.

2. Identify the bottleneck

Common bottlenecks: CPU saturation, memory exhaustion, disk I/O wait, network congestion, process limits. Name which one the measurements point to before tuning.

3. Optimization strategies

For CPU: identify CPU-intensive processes, check for runaway processes, consider nice/renice, review cron jobs, optimize application code.

For memory: check for leaks, review swap usage, adjust swappiness, kill memory hogs, add RAM if genuinely needed.

For disk: check usage, clean up old files, tune the I/O scheduler, consider an SSD, check for a failing disk with smartctl.

For network: check bandwidth, review firewall rules, tune network settings, check for attacks.

4. System tuning

Kernel parameters in /etc/sysctl.conf: vm.swappiness, fs.file-max, net.core parameters.

Service optimization: disable unused services, tune service configs, review startup items.

Resource limits in /etc/security/limits.conf: open-file limits, process limits, memory limits.

5. Monitoring setup

Set up ongoing monitoring: htop for a real-time view, logging for historical data, alerts for issues, and recorded performance baselines.

Read the full file on GitHub · 95 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 · 95 lines · 56 tokens per session scan A 342cab63ef1f

Subscribe to this mod's changes

sysadmin-performance is a skill published in the GitHub repository HermeticOrmus/linux-sysadmin-skills (2 stars, last pushed 3mo ago), licensed MIT. It adds 56 tokens to every session and 620 once invoked, about $0.0003 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.

Related

Other skills, from other repositories