What is cmux-diagnostics?

A read-only health check for cmux, a macOS terminal app, and its connections to coding agents. It collects safe diagnostic information about commands, sockets, settings, hooks, notifications, session restore, browser automation, and agent resuming.

Use it to create a support report, test the cmux command-line tool and socket, inspect relevant settings, and diagnose hooks, notifications, restored sessions, browser automation, or agent-resume problems.

It helps explain why cmux controls or agent-related features are not working without exposing prompt logs, tokens, session stores, or secret configuration.

cmux-diagnostics — Skill for Codex by disler

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 disler/learning-cmux-with-agents --skill cmux-diagnostics

Clone the repo

git clone --depth 1 https://github.com/disler/learning-cmux-with-agents

Made for: 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/disler/learning-cmux-with-agents/cmux-diagnostics/github.svg)](https://agentmods.dev/skills/disler/learning-cmux-with-agents/cmux-diagnostics)

Your own site

<a href="https://agentmods.dev/skills/disler/learning-cmux-with-agents/cmux-diagnostics"><img src="https://agentmods.dev/badge/skills/disler/learning-cmux-with-agents/cmux-diagnostics/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/disler/learning-cmux-with-agents/cmux-diagnostics"><img src="https://agentmods.dev/badge/skills/disler/learning-cmux-with-agents/cmux-diagnostics.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 831 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.

Model	Per session	Once invoked
Fable 5.1	$0.00063	$0.00831
Opus 5	$0.00032	$0.00415
Sonnet 5	$0.00013	$0.00166
Haiku 4.5	$0.00006	$0.00083

Measured 10d ago against content hash 315bab38550d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

cmux-diagnostics 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 10d 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:

cmux-diagnostics — 95% identical, 2 lines differ

ai_docs/cmux-skills/cmux-diagnostics/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.

cmux Diagnostics

Use this skill to collect and interpret support-safe cmux diagnostics for end users. Default to read-only checks. Do not dump hook config files, session stores, prompt logs, tokens, or environment secrets.

Quick Report

Run the bundled read-only diagnostic script first:

# From a cmux checkout
skills/cmux-diagnostics/scripts/cmux-diagnostics

# From an installed skill
~/.agents/skills/cmux-diagnostics/scripts/cmux-diagnostics

# From a Codex-only skills.sh install
~/.codex/skills/cmux-diagnostics/scripts/cmux-diagnostics

Use --include-context only when workspace names, cwd paths, and current cmux identifiers are relevant to the user-reported issue:

skills/cmux-diagnostics/scripts/cmux-diagnostics --include-context

What to Check

CLI and socket health:
```
command -v cmux
cmux ping
cmux capabilities --json
```
If socket commands fail, check whether the agent is running inside a cmux terminal and whether socket automation is enabled.
Settings health:
```
~/.agents/skills/cmux-settings/scripts/cmux-settings validate
~/.agents/skills/cmux-settings/scripts/cmux-settings get terminal.autoResumeAgentSessions
```
If the user installed with skills.sh, use ~/.codex/skills/cmux-settings/scripts/cmux-settings instead. If terminal.autoResumeAgentSessions is false, cmux restores panes but will not automatically resume saved agent sessions.
Hook installation:
```
cmux hooks setup --agent codex
cmux hooks setup --agent opencode
cmux hooks setup
```
Only run install or uninstall commands after the user agrees. cmux hooks setup installs supported agents found on PATH and skips missing agents.
Session restore evidence:
```
ls -lh ~/.cmuxterm/*-hook-sessions.json 2>/dev/null
```
Missing session stores usually means the agent has not run inside cmux since hooks were installed, hooks are disabled, or the agent integration does not support resume capture.

Read the full file on GitHub · 95 lines

Files

What ships with it

2 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.

10d ago First seen · 95 lines · 63 tokens per session scan A 315bab38550d

Subscribe to this mod's changes

cmux-diagnostics is a skill published in the GitHub repository disler/learning-cmux-with-agents (109 stars, last pushed 2mo ago), licensed MIT. It adds 63 tokens to every session and 831 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 2026-08-30.

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