---
name: cmux Diagnostics
slug: cmux-diagnostics
category: DevOps
description: cmux Diagnostics runs read-only checks to diagnose cmux CLI, socket, settings, hook, session restore, and notification issues. Use it when cmux hooks, agent resume, or notifications are not working, or when asking for a health check or support-safe debug summary.
github: "https://github.com/manaflow-ai/cmux/tree/main/skills/cmux-diagnostics"
language: Swift
stars: 26034
forks: 2205
install: "npx degit https://github.com/manaflow-ai/cmux/tree/main/skills/cmux-diagnostics ~/.claude/skills/cmux-diagnostics"
installs_to: ~/.claude/skills/cmux-diagnostics
source_path: skills/cmux-diagnostics/SKILL.md
collection_size: 20
category_size: 798
collection_url: "https://dirskills.com/collections/manaflow-ai/cmux"
added: 2026-08-14T07:12:06.402Z
last_synced: 2026-08-14T07:12:06.402Z
canonical_url: "https://dirskills.com/skills/cmux-diagnostics"
---

# cmux Diagnostics

cmux Diagnostics runs read-only checks to diagnose cmux CLI, socket, settings, hook, session restore, and notification issues. Use it when cmux hooks, agent resume, or notifications are not working, or when asking for a health check or support-safe debug summary.

**Install:**

```bash
npx degit https://github.com/manaflow-ai/cmux/tree/main/skills/cmux-diagnostics ~/.claude/skills/cmux-diagnostics
```

## README

# cmux Diagnostics

Collect and interpret support-safe cmux diagnostics for end users. Default to read-only checks. Never dump hook config files, session stores, prompt logs, tokens, or environment secrets.

## Quick report

Run the bundled read-only script first, from whichever install path exists:

```bash
skills/cmux-diagnostics/scripts/cmux-diagnostics            # cmux checkout
~/.agents/skills/cmux-diagnostics/scripts/cmux-diagnostics  # installed skill
~/.codex/skills/cmux-diagnostics/scripts/cmux-diagnostics   # Codex-only skills.sh install
```

Add `--include-context` only when workspace names, cwd paths, and current cmux identifiers are relevant to the reported issue.

## What to check

1. **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.
2. **Settings health**: `cmux-settings validate` and `cmux-settings get terminal.autoResumeAgentSessions` (from `~/.agents/skills/cmux-settings/scripts/`, or `~/.codex/skills/...` for a `skills.sh` install). When `terminal.autoResumeAgentSessions` is false, cmux restores panes but does not resume saved agent sessions.
3. **Hook installation**: `cmux hooks setup --agent codex`, `--agent opencode`, or bare `cmux hooks setup` (installs supported agents found on PATH, skips missing ones). Run install or uninstall commands only after the user agrees.
4. **Session restore evidence**: `ls -lh ~/.cmuxterm/*-hook-sessions.json 2>/dev/null`. Missing stores usually mean the agent has not run inside cmux since hooks were installed, hooks are disabled, or the integration does not support resume capture.
5. **Notification path**: `cmux notify "cmux diagnostic test"`, only when the user is ready for a visible test notification.

## Interpretation

- `cmux` not found: the CLI is not installed or not on PATH for this shell.
- `cmux ping` fails: the app is closed, unreachable through the current socket path, or automation access is disabled.
- No `CMUX_WORKSPACE_ID` or `CMUX_SURFACE_ID`: the command is running outside a cmux terminal. Some hooks intentionally no-op there.
- Hook config but no session store: run one supported agent inside cmux after installing hooks, then re-check.
- Session store but no agents on restore: check `terminal.autoResumeAgentSessions` and whether the saved executable still exists on PATH.
- Settings validation fails: fix the config first. Invalid config makes later symptoms misleading.

## Rules

- Stay read-only until the user asks to fix something.
- Never print raw hook files, session JSON, prompt logs, shell history, tokens, or API keys. Summarize file presence, size, modified time, and marker presence instead.
- Prefer a narrow fix such as `cmux hooks setup --agent codex` over reinstalling every integration.
- After a fix, rerun the diagnostic script and report the changed lines.