cmux-shared-behavior

cmux-shared-behavior is a skill for Codex from disler/learning-cmux-with-agents. It costs 57 tokens per session (252 once invoked), scanned A, original, MIT.

Guidance for keeping one shared implementation path when the same app behavior is available through shortcuts, menus, settings, a command line, or tests.

In plain words
What is it for?
Use it when changing shared behavior, optimistic updates, or regression coverage across multiple user interfaces.
Why use it?
It reduces bugs caused by different entry points implementing the same action differently, especially when an update fails and must be rolled back.

Skill for Codex

Written for Codex: agents/openai.yaml present.

Good fit Use it when changing shared behavior, optimistic updates, or regression coverage across multiple user interfaces.

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Install with agentmods
npx agentmods add skills/disler/learning-cmux-with-agents/cmux-shared-behavior
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add disler/learning-cmux-with-agents --skill cmux-shared-behavior
Clone the repo
git clone --depth 1 https://github.com/disler/learning-cmux-with-agents

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.

agentmods badge for cmux-shared-behavior

README.md
[![agentmods](https://agentmods.dev/badge/skills/disler/learning-cmux-with-agents/cmux-shared-behavior/github.svg)](https://agentmods.dev/skills/disler/learning-cmux-with-agents/cmux-shared-behavior)
Your own site
<a href="https://agentmods.dev/skills/disler/learning-cmux-with-agents/cmux-shared-behavior"><img src="https://agentmods.dev/badge/skills/disler/learning-cmux-with-agents/cmux-shared-behavior/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.

agentmods 80×15 button for cmux-shared-behavior

Your own site · 80×15
<a href="https://agentmods.dev/skills/disler/learning-cmux-with-agents/cmux-shared-behavior"><img src="https://agentmods.dev/badge/skills/disler/learning-cmux-with-agents/cmux-shared-behavior.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 252 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00057 $0.00252
Opus 5 $0.00028 $0.00126
Sonnet 5 $0.00011 $0.00050
Haiku 4.5 $0.00006 $0.00025

Measured 9d ago against content hash 20444b308c01, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

cmux-shared-behavior scanned grade A with 0 findings 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 9d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

ai_docs/cmux-skills/cmux-shared-behavior/SKILL.md · 39 lines

What it actually says

cmux Shared Behavior

Use one shared action/model path when behavior is exposed through multiple entrypoints.

Shared entrypoints

When a behavior is exposed through multiple surfaces, implement one shared action/model path and verify every entrypoint that should invoke it.

Common entrypoints include:

  • keyboard shortcut
  • command palette
  • context menu
  • CLI/socket command
  • settings UI
  • debug menu

Do not patch one surface while leaving the others with duplicated logic.

Optimistic updates

For optimistic UI or CLI updates:

  • keep one mutation path
  • record pending state with a request id or previous snapshot
  • reconcile from the authoritative result
  • handle failure with an explicit rollback or error state

Do not let each entrypoint maintain its own optimistic copy.

Missed-bug coverage

When a user says tests missed a bug, add or adjust behavior-level coverage around the exact repro path before claiming the fix is complete.

Files

What ships with it

1 file 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.

  1. 9d ago First seen · 39 lines · 57 tokens per session scan A 20444b308c01

Subscribe to this mod's changes

cmux-shared-behavior is a skill published in the GitHub repository disler/learning-cmux-with-agents (109 stars, last pushed 2mo ago), licensed MIT. It adds 57 tokens to every session and 252 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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