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.
npx agentmods add skills/leejuoh/claude-code-zero/cmux-browsernpx skills add LeeJuOh/claude-code-zero --skill cmux-browsergit clone --depth 1 https://github.com/LeeJuOh/claude-code-zeroWrote 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.
[](https://agentmods.dev/skills/leejuoh/claude-code-zero/cmux-browser)<a href="https://agentmods.dev/skills/leejuoh/claude-code-zero/cmux-browser"><img src="https://agentmods.dev/badge/skills/leejuoh/claude-code-zero/cmux-browser.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00057 | $0.01509 |
| Opus 5 | $0.00028 | $0.00754 |
| Sonnet 5 | $0.00011 | $0.00302 |
| Haiku 4.5 | $0.00006 | $0.00151 |
Grade A, and why
cmux-browser scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 149 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Browser Automation with cmux
Use this skill for browser tasks inside cmux webviews. Requires cmux environment ($CMUX_WORKSPACE_ID). Outside cmux, this skill's features are unavailable.
Core Workflow
- Open or target a browser surface.
- Verify navigation with
get urlbefore waiting or snapshotting. - Snapshot (
--interactive) to get fresh element refs. - Act with refs (
click,fill,type,select,press). - Wait for state changes.
- Re-snapshot after DOM/navigation changes.
cmux --json browser open https://example.com
# use returned surface ref, for example: surface:7
cmux browser surface:7 get url
cmux browser surface:7 wait --load-state complete --timeout-ms 15000
cmux browser surface:7 snapshot --interactive
cmux browser surface:7 fill e1 "hello"
cmux --json browser surface:7 click e2 --snapshot-after
cmux browser surface:7 snapshot --interactive
Surface Targeting
# identify current context
cmux identify --json
# open routed to a specific topology target
cmux browser open https://example.com --workspace workspace:2 --window window:1 --json
Notes:
- CLI output defaults to short refs (
surface:N,pane:N,workspace:N,window:N). - UUIDs are still accepted on input; only request UUID output when needed (
--id-format uuids|both). - Keep using one
surface:Nper task unless you intentionally switch.
Wait Support
cmux browser <surface> wait --selector "#ready" --timeout-ms 10000
cmux browser <surface> wait --text "Success" --timeout-ms 10000
cmux browser <surface> wait --url-contains "/dashboard" --timeout-ms 10000
cmux browser <surface> wait --load-state complete --timeout-ms 15000
cmux browser <surface> wait --function "document.readyState === 'complete'" --timeout-ms 10000
Common Flows
Form Submit
cmux --json browser open https://example.com/signup
cmux browser surface:7 get url
cmux browser surface:7 wait --load-state complete --timeout-ms 15000
cmux browser surface:7 snapshot --interactive
cmux browser surface:7 fill e1 "Jane Doe"
cmux browser surface:7 fill e2 "[email protected]"
cmux --json browser surface:7 click e3 --snapshot-after
cmux browser surface:7 wait --url-contains "/welcome" --timeout-ms 15000
cmux browser surface:7 snapshot --interactive
What ships with it
9 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.
- references/authentication.md 3.0 KB
- references/commands.md 4.5 KB
- references/proxy-support.md 805 B
- references/session-management.md 1.8 KB
- references/snapshot-refs.md 1.5 KB
- references/video-recording.md 1.0 KB
- templates/authenticated-session.sh 555 B runs code
- templates/capture-workflow.sh 381 B runs code
- templates/form-automation.sh 360 B runs code
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.
- 3d ago First seen · 149 lines · 57 tokens per session scan A 212950e866cd
cmux-browser is a skill published in the GitHub repository LeeJuOh/claude-code-zero (51 stars, last pushed 4d ago), licensed MIT. It adds 57 tokens to every session and 1,509 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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