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

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.