| name | cmux-diagnostics |
| description | Run end-user cmux diagnostics. Use when cmux hooks, notifications, session restore, settings, browser automation, socket access, CLI control, or agent resume behavior is not working, or when the user asks for a cmux health check, doctor report, or support-safe debug summary. |
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
~/.agents/skills/cmux-diagnostics/scripts/cmux-diagnostics
~/.codex/skills/cmux-diagnostics/scripts/cmux-diagnostics
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.
