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 skills add disler/learning-cmux-with-agents --skill cmux-testinggit clone --depth 1 https://github.com/disler/learning-cmux-with-agentsWrote 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/disler/learning-cmux-with-agents/cmux-testing)<a href="https://agentmods.dev/skills/disler/learning-cmux-with-agents/cmux-testing"><img src="https://agentmods.dev/badge/skills/disler/learning-cmux-with-agents/cmux-testing/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.
<a href="https://agentmods.dev/skills/disler/learning-cmux-with-agents/cmux-testing"><img src="https://agentmods.dev/badge/skills/disler/learning-cmux-with-agents/cmux-testing.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00044 | $0.01153 |
| Opus 5 | $0.00022 | $0.00576 |
| Sonnet 5 | $0.00009 | $0.00231 |
| Haiku 4.5 | $0.00004 | $0.00115 |
Grade A, and why
cmux-testing 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.
How it starts
The opening of the file, as written. The whole thing — 47 lines — stays where its author put it; the contents beside it link to each section on GitHub.
cmux Testing
Regression test commit policy
When adding a regression test for a bug fix, use a two-commit structure so CI proves the test catches the bug:
- Commit 1: Add the failing test only (no fix). CI should go red.
- Commit 2: Add the fix. CI should go green.
This makes it visible in the GitHub PR UI that the test genuinely fails without the fix.
Test quality policy
- Do not add tests that only verify source code text, method signatures, AST fragments, or grep-style patterns.
- Do not add tests that read checked-in metadata or project files such as
Resources/Info.plist,project.pbxproj,.xcconfig, or source files only to assert that a key, string, plist entry, or snippet exists. - Tests must verify observable runtime behavior through executable paths (unit/integration/e2e/CLI), not implementation shape.
- For metadata changes, prefer verifying the built app bundle or the runtime behavior that depends on that metadata, not the checked-in source file.
- If a behavior cannot be exercised end-to-end yet, add a small runtime seam or harness first, then test through that seam.
- If no meaningful behavioral or artifact-level test is practical, skip the fake regression test and state that explicitly.
Test framework
Swift Testing is the current Apple-supported primitive for tests on this codebase (shipped with Swift 6 / Xcode 16, supported on the macOS versions we target). Use it for everything that is not a UI test.
- Default to Swift Testing for all unit and integration tests.
import Testing, annotate tests with@Test, group with@Suite, assert with#expect(...)andtry #require(...). Do not write new tests withimport XCTestunless they are UI tests. - UI tests stay on XCTest / XCUITest. Swift Testing does not support UI testing (no
XCUIApplicationintegration). Files undercmuxUITests/continue to useXCTestCase+XCUIApplication. Do not migrate them and do not try to bridge Swift Testing into UI tests. - New test targets start on Swift Testing. Every new Swift package's
Tests/<Name>Tests/directory (e.g.Packages/macOS/CmuxSettings/Tests/CmuxSettingsTests/) should ship with Swift Testing from the first commit. Xcode 16 auto-detects the framework based on theimport Testingstatement; no extraPackage.swiftconfiguration is required. - Migration guide when touching an existing XCTest test. Convert in place:
XCTestCasesubclass becomes a@Suite struct(orfinal classif you need a reference type); eachfunc testFoo()becomes@Test func foo();XCTAssertEqual(a, b)becomes#expect(a == b);XCTAssertTrue(cond)becomes#expect(cond);XCTUnwrap(x)becomestry #require(x);XCTFail("msg")becomesIssue.record("msg").setUp()becomesinit()on the suite;tearDown()becomesdeinit. Async setup isasync init(). Do not bulk-rewrite untouched tests; migrate incrementally as a side effect of editing the file. - Parameterized tests use
@Test(arguments: [...]). Prefer this over duplicate test methods. - Parallelization and shared state. Swift Testing runs tests in parallel by default, including across suites. If a suite genuinely needs ordering or guards shared mutable state, annotate it with
.serializedinstead of adding locks or sleeps. - Tags with
@Test(.tags(.something))(or on a@Suite) let CI and local runs filter selectively.
What ships with it
4 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.
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.
- 9d ago First seen · 47 lines · 44 tokens per session scan A 070f7b29026f
cmux-testing is a skill published in the GitHub repository disler/learning-cmux-with-agents (109 stars, last pushed 2mo ago), licensed MIT. It adds 44 tokens to every session and 1,153 once invoked, about $0.0002 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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