Proctmux Config

Use this skill to produce accurate proctmux.yaml files for proctmux users. Assume the reader is an external consumer who has the proctmux binary and project files, but no access to internal proctmux project files.

Before writing or changing a config, read references/proctmux-yaml.md. It contains a standalone option reference, defaults, lifecycle semantics, discovery behavior, and legacy fields that are currently ignored. Do not tell the user to inspect proctmux internals.

Workflow

1. Identify the user's goal: new config, process entry, lifecycle behavior, keybindings, layout/style, discovery, or troubleshooting.
2. If an existing config is available, inspect it first and preserve unrelated entries. Do not rewrite the whole file unless the user asks for a full replacement.
3. Use active option names only. Avoid legacy ignored fields unless you are explicitly removing or explaining them.
4. Prefer the smallest config that expresses the requested behavior. Defaults cover most UI and lifecycle settings.
5. For each process, choose either shell or cmd:
   • Use shell for pipes, redirects, globs, variable expansion, compound commands, or shell builtins.
   • Use cmd for direct executable + argument lists where shell interpolation is not needed.
   • If both are set, proctmux gives shell precedence, so avoid setting both.
6. When adding stop/restart behavior, document the effective signal and timeout. stop is a POSIX signal number, and stop_timeout_ms controls escalation to SIGKILL.
7. When adding on_kill, make it idempotent. It runs only for user-initiated stops/restarts, with the process cwd and env, and has a 30 second hook timeout.
8. Validate from the user's perspective: the config should be usable with proctmux -f path/to/proctmux.yaml, or discovered automatically when named proctmux.yaml, proctmux.yml, procmux.yaml, or procmux.yml.
9. Return YAML in a fenced yaml block unless editing a repository file directly. If editing directly, summarize the changed file and the relevant options used.

Validation Checklist

Check generated configs against these constraints:

• Top-level active keys are general, layout, style, keybinding, shell_cmd, log_file, stdout_debug_log_file, and procs.
• general.procs_from_make_targets and general.procs_from_package_json are per-source discovery toggles; configless startup enables both automatically.
• procs is a map from display label to process config. Labels may contain spaces when quoted.
• List-valued fields must be YAML sequences of strings, not comma-separated strings.
• Boolean fields should be YAML booleans (true/false).
• Integer fields should be decimal numbers.
• layout.processes_list_width should be between 1 and 100; values <= 0 or > 100 reset to the default 30.
• style color values currently support ANSI-style names and numeric ANSI color indexes; do not assume arbitrary hex colors are rendered by the TUI.
• shell_cmd is the global command prefix used for process shell strings. Effective default is ["sh", "-c"].
• terminal_rows and terminal_cols apply to each process PTY and default to 24 and 80 when omitted or non-positive.
• Unknown fields are ignored with warnings; do not rely on ignored legacy fields for behavior.

Common Patterns

Node app with PATH additions

procs:
  web:
    shell: "npm run dev"
    cwd: "."
    add_path: ["./node_modules/.bin"]
    autostart: true
    categories: ["frontend"]

Direct command without shell interpolation

procs:
  worker:
    cmd: ["python", "-m", "myapp.worker"]
    env:
      WORKER_CONCURRENCY: "4"
    categories: ["worker"]

Lifecycle cleanup

procs:
  stack:
    shell: "docker compose up"
    stop: 2
    stop_timeout_ms: 10000
    on_kill: ["docker", "compose", "down"]

Output Style

When the user asks for a new file, provide a complete proctmux.yaml with short comments only where they clarify a non-obvious choice. When the user asks to modify an existing config, show only the relevant diff or edit the file directly if you have workspace access.

When explaining options, cite the exact YAML path, such as procs.web.stop_timeout_ms or layout.hide_process_list_when_unfocused.