Agent skill · software engineering · sickn33
cmux
Control cmux workspaces, panes, surfaces, and agent sessions safely from macOS terminal workflows.
Why this skill is useful
Adds specific commands and patterns for managing cmux workspaces and agents that the AI wouldn't reliably generate on its own.
What it needs
Requires cmux installed locally. About 8k tokens when loaded. Last updated 2026-08-07. 44,571 stars on the source repository.
What this skill does
Supporting material availability This catalog copy contains the inline guidance below, but does not include the following supporting paths. They are external prerequisites, not bundled files: <support-root>/references/socket-api.md Obtain the required material from the declared upstream source, or from a user-provided installation of that source. Resolve each path relative to that installation, inspect its contents, and verify any applicable license and execution prerequisites. Do not run a command or claim a referenced procedure was followed until its required file exists. Do not fabricate the missing scripts or treat an unrelated file with the same name as equivalent. Independent steps fully documented here can proceed within the user’s authorized scope; report any dependent step as unavailable. cmux Control When to Use Use when you need to inspect, create, close, or rearrange cmux panes, surfaces, or workspaces. Use when you need to send input to or monitor agents running inside cmux. cmux is a native macOS terminal app for running multiple AI coding agents in parallel. It exposes a CLI (cmux) and a Unix-socket JSON-RPC API (/tmp/cmux.sock) for full topology and browser control. Core Concepts Window — top-level macOS cmux window Workspace — sidebar tab within a window (one git branch / project context) Pane — split region inside a workspace Surface — tab inside a pane (terminal or browser) Handles default to short refs (workspace:2, pane:1, surface:7); UUIDs accepted as input. Add --id-format uuids both for UUID output. Ref syntax — get this right or fail silently Always use PREFIXED refs (pane:38, surface:46). A bare number is treated as an INDEX, not an ID — --surface 46 means "the surface at index 46" (usually nonexistent → silent failure), NOT surface:46. read-screen and capture-pane have NO --pane flag — they target --workspace or --surface only. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills sickn33/cmux--497bb9