What is cmux-workspace?

A set of instructions for working in the current cmux workspace, a terminal environment with workspaces, split panes, and terminal or browser sessions.

Identifying the current workspace, terminal surface, and connection socket. It supports automation across panes and sessions without interfering with unrelated cmux workspaces.

It helps the agent target the workspace that started the task, even when another workspace is currently visible. This reduces the risk of sending commands to the wrong session.

cmux-workspace — Skill for Codex by manaflow-ai

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo

git clone --depth 1 https://github.com/manaflow-ai/cmux-skills

agentmods

npx agentmods add skills/manaflow-ai/cmux-skills/cmux-workspace

Made for: Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/manaflow-ai/cmux-skills/cmux-workspace/github.svg)](https://agentmods.dev/skills/manaflow-ai/cmux-skills/cmux-workspace)

Your own site

<a href="https://agentmods.dev/skills/manaflow-ai/cmux-skills/cmux-workspace"><img src="https://agentmods.dev/badge/skills/manaflow-ai/cmux-skills/cmux-workspace/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/manaflow-ai/cmux-skills/cmux-workspace"><img src="https://agentmods.dev/badge/skills/manaflow-ai/cmux-skills/cmux-workspace.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,492 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

Socket pass 13 Jun 2026
Snyk pass 13 Jun 2026
NVIDIA SkillSpector pass 7 Sept 2026

How audits are shown

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00047	$0.03492
Opus 5	$0.00023	$0.01746
Sonnet 5	$0.00009	$0.00698
Haiku 4.5	$0.00005	$0.00349

Measured 12d ago against content hash bf070d8d77de, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

cmux-workspace scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -fsS "http://127.0.0.1:<printed-port>"

skills/cmux-workspace/SKILL.md · 297 lines

How it starts

The opening of the file, as written. The whole thing — 297 lines — stays where its author put it; the contents beside it link to each section on GitHub.

cmux Workspace

Use this skill when a task should be scoped to the cmux workspace that invoked the agent. A workspace is the sidebar tab-like unit in cmux. It contains split panes, and each pane contains one or more surfaces. A surface is the terminal or browser session the user interacts with.

Default Rule

Scope actions to the current caller workspace unless the user explicitly asks for another workspace, another window, or global state.

Do not assume the visually focused cmux workspace is the right target. An agent can be running in one workspace while the user is looking at another. Prefer the caller environment first:

printf 'workspace=%s\nsurface=%s\nsocket=%s\n' \
  "${CMUX_WORKSPACE_ID:-}" \
  "${CMUX_SURFACE_ID:-}" \
  "${CMUX_SOCKET_PATH:-}"
cmux identify --json

Use CMUX_WORKSPACE_ID as the default workspace anchor and CMUX_SURFACE_ID as the default caller terminal/surface anchor. If those are missing, use cmux identify --json and be explicit that you are using the currently focused cmux context.

Non-Disruptive Automation

The user may be visually focused on a different workspace, window, or app while an agent works in the caller workspace. Treat layout and focus as separate concerns. Never call focus-changing verbs speculatively.

Never call these without an explicit user ask:

select-workspace switches the visible sidebar tab.
focus-pane / focus-panel yanks pane or surface focus.
tab-action with focus-changing actions.

These are user-affecting actions, like clicks. The rule applies even inside the caller's own workspace, since the user may be looking elsewhere.

Build layout additively, in one shot. Prefer commands that create a new pane already populated with the right surface:

# pane and content in one call, no follow-up needed
cmux new-pane --workspace "${CMUX_WORKSPACE_ID}" --type browser --direction right --url "http://127.0.0.1:8765"
cmux new-pane --workspace "${CMUX_WORKSPACE_ID}" --type terminal --direction down

Read the full file on GitHub · 297 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

12d ago First seen · 297 lines · 47 tokens per session scan A bf070d8d77de

Subscribe to this mod's changes

cmux-workspace is a skill published in the GitHub repository manaflow-ai/cmux-skills (31 stars, last pushed 3d ago), licensed MIT. It adds 47 tokens to every session and 3,492 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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