cmux-diagnostics

SKILL.md

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:

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

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: 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.

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.

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.

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.