Agent skill

cmux Contributor Dev Workflow

by disler in disler/learning-cmux-with-agents

Contributor rules for the cmux repo: tagged Debug builds through reload.sh, first-time setup, Xcode project normalization and per-tag sidebar extension points.

MITAuto-check passedDevelopment

Install cmux Contributor Dev Workflow

skills CLI
$ npx skills add disler/learning-cmux-with-agents --skill cmux-dev-workflow -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install disler/learning-cmux-with-agents cmux-dev-workflow --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/disler/learning-cmux-with-agents.git skills-src && mkdir -p .claude/skills && cp -r skills-src/ai_docs/cmux-skills/cmux-dev-workflow .claude/skills/cmux-dev-workflow && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
cmux-dev-workflow
GitHub stars
115
Token cost
~1.5k tokens
SKILL.md length
653 words
Files
5 (incl. references)
Skills in repo
5
Repo updated
First seen
Licence
MIT

At a glance

Contributor rules for the cmux repo: tagged Debug builds through reload.sh, first-time setup, Xcode project normalization and per-tag sidebar extension points.

  • Setting up the cmux repository for the first time
  • SKILL.md covers Tagged local dev, Initial setup, Xcode toolchain and Sidebar extension point (dev…, plus 1 more section
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
  • Building and reloading a tagged Debug app after a code change

What it does

After any code change the agent builds the Debug app with `./scripts/reload.sh` and a short tag. By default the script builds without launching, and `--launch` opens the app. Bare `xcodebuild` and untagged `cmux DEV.app` are off limits, because untagged builds share the default debug socket and bundle ID with other agents, which causes conflicts and stolen focus. CLI or socket testing against a tagged build goes through `scripts/cmux-debug-cli.sh` with `CMUX_TAG` set, never the `/tmp/cmux-cli` symlink, and cmuxd is rebuilt for release with `zig build -Doptimize=ReleaseFast`.

Initial setup runs `./scripts/setup.sh`, which initializes submodules, builds GhosttyKit and installs a pre-commit hook that runs `scripts/normalize-pbxproj.py` on a staged `project.pbxproj` to sort the high-churn sections. CI runs `scripts/check-pbxproj.sh` to enforce the pin. The team is pinned to Xcode 26.x through `.xcode-version`, with `objectVersion = 60`, and changing that needs a team decision. Each tagged dev build also gets its own ExtensionKit sidebar extension point so concurrent builds do not collide. Three reference files go deeper on tagging and normalization.

When your agent uses it

  • Setting up the cmux repository for the first time
  • Building and reloading a tagged Debug app after a code change
  • Editing the Xcode project file without creating noisy diffs
  • Adding or testing a sidebar extension in a tagged build

Example prompts

  • “Set up my cmux checkout and install the pre-commit hook.”
  • “Rebuild the Debug app with the tag sidebar-fix and launch it.”
  • “Why does CI fail on my project.pbxproj change?”
  • “Add a sidebar extension and make sure it works in a tagged dev build.”

Requirements

  • A checkout of the cmux repository
  • Xcode 26.x
  • Zig for building cmuxd

What it can do on your machine

Read from SKILL.md and the folder at commit 6eaacab. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md (its code samples are bash).

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

cmux Contributor Dev Workflow loads about 1.5k tokens when it runs, and up to ~2.8k if it reads all its reference files. Until then it costs about 69 tokens; SKILL.md has 653 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~69
When it runs · the whole SKILL.md, loaded when a task matches
~1.5k
With references · SKILL.md plus every file in references/, read only if the agent opens them
~2.8k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from disler/learning-cmux-with-agents at commit 6eaacab, republished under its MIT licence (© disler). 653 words, ~1,500 tokens.

Download SKILL.mdSave it as .claude/skills/cmux-dev-workflow/SKILL.md (or your agent's skills folder). This skill also uses 4 other files; get the full folder from GitHub.
name
cmux-dev-workflow
description
Contributor workflow rules for cmux setup, Xcode project normalization, tagged sidebar ExtensionKit development, and dev builds. Use when setting up the cmux repo, changing Xcode project files, adding sidebar extensions, or working with tagged debug builds.

cmux Dev Workflow

Tagged local dev

After making code changes, always run the reload script with a tag to build the Debug app:

bash
./scripts/reload.sh --tag <short-tag>

By default, reload.sh builds but does not launch the app. Pass --launch only when you need to open it automatically.

Never run bare xcodebuild or open an untagged cmux DEV.app. Untagged builds share the default debug socket and bundle ID with other agents, causing conflicts and stealing focus.

For CLI or socket dogfood against a tagged Debug app, use the tag-bound helper and set CMUX_TAG:

bash
CMUX_TAG=<tag> scripts/cmux-debug-cli.sh list-workspaces

Do not use /tmp/cmux-cli for tagged dogfood. That symlink points at the most recently reloaded build.

When rebuilding cmuxd for release/bundling, always use ReleaseFast:

bash
cd cmuxd && zig build -Doptimize=ReleaseFast

Initial setup

Run the setup script to initialize submodules, build GhosttyKit, and install the pbxproj normalization pre-commit hook:

bash
./scripts/setup.sh

Xcode toolchain

The team is pinned to Xcode 26.x. .xcode-version records the major; cmux.xcodeproj/project.pbxproj carries objectVersion = 60, which is what Xcode 26 writes by default. (objectVersion 77 is reserved for projects that adopt synchronized folder groups, which cmux does not use yet. Bumping to a different value requires a deliberate team decision.)

scripts/setup.sh installs a tracked pre-commit hook (scripts/git-hooks/pre-commit) that runs scripts/normalize-pbxproj.py on any staged cmux.xcodeproj/project.pbxproj, sorting the high-churn sections so Xcode's nondeterministic reordering never reaches a commit. The hook is idempotent. CI runs scripts/check-pbxproj.sh to enforce both the objectVersion pin and normalization, so anyone who skips the hook (or never ran setup) gets a clear failure on their PR.

.xcode-version is the single source of truth. To bump the pin: edit .xcode-version, open cmux.xcodeproj in the new Xcode (which rewrites objectVersion automatically when it touches the file), and add a case for the new Xcode major in scripts/check-pbxproj.sh mapping it to the objectVersion that major writes.

Sidebar extension point (dev tagging)

Each tagged dev build gets its own ExtensionKit sidebar extension point so concurrent dev builds don't collide. Three build settings drive this:

  • CMUX_SIDEBAR_EXTENSION_POINT_ID (default com.cmuxterm.app.cmux.sidebar): the extension point identifier baked into Info.plist at build time.
  • CMUX_BUNDLE_ID_SUFFIX (default empty): inserted into the app and appex bundle ids so a tagged extension gets a distinct identity that pkd records separately.
  • CMUX_DISPLAY_NAME_SUFFIX (default empty): appended to the appex CFBundleDisplayName. The OS groups sidebar extensions by display name for the enable/disable + availability counts the host reads (AppExtensionIdentity exposes only bundleIdentifier, localizedName, extensionPointIdentifier, id — cmux already keys its own identity off the stable bundleIdentifier, but the OS-level grouping is by name). Two same-named appexes installed side by side (a base build and a tagged build) are treated as one logical extension, so toggling one perturbs the other; a per-tag display name keeps them distinct.
Show full SKILL.md (222 more words)Show less

The host resolves its point id at runtime from the Info.plist key CMUXSidebarExtensionPointIdentifier via CmuxSidebarExtensionPoint.identifier(in:). ./scripts/reload.sh --tag <tag> scopes the host point to com.cmuxterm.app.debug.<tag>.cmux.sidebar. ./scripts/reload-extension.sh --tag <tag> [--host-bundle-id <id>] [--example sample|tabs|both] builds a matching tag-scoped sample extension, passing CMUX_SIDEBAR_EXTENSION_POINT_ID=<host-bundle-id>.cmux.sidebar, CMUX_BUNDLE_ID_SUFFIX=.<tag>, and CMUX_DISPLAY_NAME_SUFFIX=" <tag>". It installs exactly what xcodebuild produced (xcodebuild ad-hoc signs with entitlements intact) — it does NOT re-sign, because a bare codesign --force --sign - strips the appex entitlements and the extension then drops its host XPC connection. pkd ingests the tagged copy because its bundle id is distinct. Verify with pluginkit -m -p <host-bundle-id>.cmux.sidebar.

To author a NEW sample extension that is tag-ready:

  • appex Info.plist: EXAppExtensionAttributes:EXExtensionPointIdentifier = $(CMUX_SIDEBAR_EXTENSION_POINT_ID).
  • add CMUX_SIDEBAR_EXTENSION_POINT_ID (default com.cmuxterm.app.cmux.sidebar), CMUX_BUNDLE_ID_SUFFIX (default empty), and CMUX_DISPLAY_NAME_SUFFIX (default empty) build settings to the app and appex targets in all build configs.
  • PRODUCT_BUNDLE_IDENTIFIER = <appBase>$(CMUX_BUNDLE_ID_SUFFIX) for the app target and <appBase>$(CMUX_BUNDLE_ID_SUFFIX).<leaf> for the appex (suffix before the appex leaf so the appex id stays prefixed by the app id).
  • appex INFOPLIST_KEY_CFBundleDisplayName (or the CFBundleDisplayName Info.plist value) = <Name>$(CMUX_DISPLAY_NAME_SUFFIX).
  • it must be ad-hoc signed by xcodebuild (Info.plist bound, entitlements intact) for pkd to ingest the tagged copy; do not re-sign post-build.

Detailed references

© disler, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 4 other files (references) in ai_docs/cmux-skills/cmux-dev-workflow of disler/learning-cmux-with-agents.

  • SKILL.md
  • agents/openai.yaml
  • references/sidebar-extension-tagging.md
  • references/tagged-builds.md
  • references/xcode-project-normalization.md

Open the folder on GitHubat commit 6eaacab

Compare with similar skills

cmux Contributor Dev Workflow next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

cmux Contributor Dev Workflow compared with similar skills
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cmux Contributor Dev Workflow this skilldisler/learning-cmux-with-agents115—~1.5kAutomated safety check: PassMIT
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Saleor Commit Workflowsaleor/saleor23k—~575Automated safety check: PassBSD-3-Clause
Qt Cpp ReviewSerial-Studio/Serial-Studio7.2k—~4.3kAutomated safety check: PassCustom licence
Qt Qml ReviewSerial-Studio/Serial-Studio7.2k—~3.7kAutomated safety check: PassCustom licence

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Works with

Categories

Questions about cmux Contributor Dev Workflow

What does cmux Contributor Dev Workflow do?

Contributor rules for the cmux repo: tagged Debug builds through reload.sh, first-time setup, Xcode project normalization and per-tag sidebar extension points. sh` and a short tag. By default the script builds without launching, and `--launch` opens the app.

When should I use cmux Contributor Dev Workflow?

cmux Contributor Dev Workflow fits situations like: setting up the cmux repository for the first time; building and reloading a tagged Debug app after a code change; editing the Xcode project file without creating noisy diffs; adding or testing a sidebar extension in a tagged build.

How do I install cmux Contributor Dev Workflow in Claude Code?

Run `npx skills add disler/learning-cmux-with-agents --skill cmux-dev-workflow -a claude-code`. Or copy the skill folder (ai_docs/cmux-skills/cmux-dev-workflow in disler/learning-cmux-with-agents) into .claude/skills/cmux-dev-workflow in your project. Claude Code loads it when a task matches its description.

How do I install cmux Contributor Dev Workflow in Codex?

Run `npx skills add disler/learning-cmux-with-agents --skill cmux-dev-workflow -a codex`. Or copy the skill folder (ai_docs/cmux-skills/cmux-dev-workflow in disler/learning-cmux-with-agents) into .agents/skills/cmux-dev-workflow in your project. Codex loads it when a task matches its description.

Can I use cmux Contributor Dev Workflow in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add disler/learning-cmux-with-agents --skill cmux-dev-workflow -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/cmux-dev-workflow, .gemini/skills/cmux-dev-workflow, .github/skills/cmux-dev-workflow and .opencode/skills/cmux-dev-workflow in your project.

What does cmux Contributor Dev Workflow need to run?

SKILL.md names no scripts, command-line tools or credentials: cmux Contributor Dev Workflow is instructions for the agent only. Our summary lists: A checkout of the cmux repository; Xcode 26.x; Zig for building cmuxd.

Does cmux Contributor Dev Workflow access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is cmux Contributor Dev Workflow safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does cmux Contributor Dev Workflow use?

cmux Contributor Dev Workflow is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does cmux Contributor Dev Workflow use?

About 1.5k tokens (SKILL.md is roughly 6k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 1.3k tokens, read only when the agent opens those files.

What are the alternatives to cmux Contributor Dev Workflow?

Skills that share tags, products or a category with cmux Contributor Dev Workflow: Codebase Knowledge Graph Q&A (Egonex-AI/Understand-Anything, 85k stars), Understand Explain (Egonex-AI/Understand-Anything, 85k stars), Saleor Commit Workflow (saleor/saleor, 23k stars) and Qt Cpp Review (Serial-Studio/Serial-Studio, 7.2k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains cmux Contributor Dev Workflow?

disler (a GitHub user) maintains it in disler/learning-cmux-with-agents, which has 115 GitHub stars. The repository holds 5 skills in this directory. The repository was last updated on June 29, 2026.

Source: disler/learning-cmux-with-agents on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.