Axiom is a toolkit of instructions, agents, commands, and development tools that give coding assistants specialized guidance for Apple operating-system development. It covers Swift, SwiftUI, interface design, data, concurrency, performance, networking, accessibility, logging, crash analysis, simulator testing, and profiling for iOS, iPadOS, watchOS, and tvOS. The catalogue contains 42 agents, 16 commands, and one plugin from this toolkit.
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 CharlesWiltgen/Axiom --skill axiom-testinggit clone --depth 1 https://github.com/CharlesWiltgen/AxiomWrote 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/charleswiltgen/axiom/axiom-testing)<a href="https://agentmods.dev/skills/charleswiltgen/axiom/axiom-testing"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-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/charleswiltgen/axiom/axiom-testing"><img src="https://agentmods.dev/badge/skills/charleswiltgen/axiom/axiom-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
- NVIDIA SkillSpector pass
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 | $0.00038 | $0.02470 |
| Opus 5.5 | $0.00015 | $0.00988 |
| Sonnet 5.5 | $0.00008 | $0.00494 |
| Haiku 4.5 | $0.00004 | $0.00247 |
Grade A, and why
axiom-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 10d 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 — 174 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Testing
You MUST use this skill for ANY testing-related question, including writing tests, debugging test failures, making tests faster, or choosing between testing approaches.
Bundled tools on Claude Code: if command -v <tool> finds nothing (hooks off or --bare), use <plugin-root>/tools/<tool> in place of the bare name; <plugin-root> is two levels above this skill's Base directory for this skill: path.
Can't launch Axiom agents? Where this router sends you to an agent, follow its procedure inline. Over MCP,
axiom_get_agentreturns it; elsewhere, read its file below, which needs only file search and read.Available here:
skills/test-failure-analyzer.md,skills/testing-auditor.md.For any other agent, over MCP
axiom_get_agentreturns it too; run its xclog, xcsym and xcprof steps with theaxiom_xclog_*,axiom_xcsym_*andaxiom_xcprof_*tools. Elsewhere, search Axiom's skills forskills/<agent>.md; if there is none, do that work yourself with this suite's skills, using any Axiom tool on yourPATH.
Quick Reference
| Symptom / Task | Reference |
|---|---|
| Writing unit tests, Swift Testing (@Test, #expect) | See skills/swift-testing.md |
| Making tests run without simulator | See skills/swift-testing.md |
| Parameterized tests, tags, traits | See skills/swift-testing.md |
| Migrating from XCTest to Swift Testing | See skills/swift-testing.md |
Warning-severity issues / cancelling a test — Issue.record(severity:), Test.cancel (OS27) |
See skills/swift-testing.md |
| Testing async/await functions | See skills/testing-async.md |
| confirmation for callbacks | See skills/testing-async.md |
| @MainActor tests, parallel execution | See skills/testing-async.md |
| Writing UI tests, XCUITest | See skills/ui-testing.md |
Driving VoiceOver from a UI test, asserting spoken output (OS27) |
See skills/ui-testing.md Pattern 7 |
Testing App Intents through the system, AppIntentsTesting (OS27) |
See skills/ui-testing.md Pattern 8, then axiom-integration (skills/app-intents-ref.md) |
| Condition-based waiting patterns | See skills/ui-testing.md |
| Recording UI Automation (Xcode 26) | See skills/ui-testing.md |
| Network conditioning, multi-factor testing | See skills/ui-testing.md |
| Testing resizable apps: dimension matrix, RTL/pseudoloc launch args, live-resize passes | See skills/ui-testing.md |
| Test Face ID/Touch ID, orientation, or simulator state from CI — devicectl | See skills/ui-testing.md |
| XCUIElement queries, waiting strategies | See skills/xctest-automation.md |
| Accessibility identifiers, test plans | See skills/xctest-automation.md |
| CI/CD test execution | See skills/xctest-automation.md |
| Record/Replay/Review workflow (Xcode 26) | See skills/ui-recording.md |
| Test plan multi-configuration replay | See skills/ui-recording.md |
| Enhancing recorded tests for stability | See skills/ui-recording.md |
Testing a generative AI feature — output isn't deterministic, so #expect(result == expected) doesn't hold (OS27) |
See axiom-ai (skills/foundation-models-evaluations.md) for the discipline, then axiom-ai (skills/foundation-models-evaluations-ref.md) for the API |
What ships with it
7 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.
- 10d ago Changed 861872a63339
- 12d ago Changed · +2 lines cf9df8a31f5c
- 13d ago Changed · +2 lines 2367a1cdd55a
- 1mo ago Changed 82f04e1560de
- 1mo ago Changed · +1 lines 4264df996d55
- 1mo ago First seen · 169 lines · 38 tokens per session scan A c11544545215
axiom-testing is a skill published in the GitHub repository CharlesWiltgen/Axiom (1,229 stars, last pushed 5d ago), licensed MIT. It adds 38 tokens to every session and 2,470 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-06.
Other skills, from other repositories
test-master
Generates test files, creates mocking strategies, analyzes code coverage, designs test architectures, and produces test plans and defect reports across functional, performance, and security testing disciplines. Use when writing unit tests, integration tests, or E2E tests; creating test strategies or automation…
designing-tests
Designs and implements testing strategies for any codebase. Use when adding tests, improving coverage, setting up testing infrastructure, debugging test failures, or when asked about unit tests, integration tests, or E2E testing.
testing-blocks
Use this when you have made AEM Edge Delivery Services code changes to blocks, scripts, or styles and need to validate them before opening a pull request. Covers unit testing for utilities and logic, browser testing with Playwright, linting, and guidance on what to test and how.
JMeter Load Testing
Load and performance testing skill using Apache JMeter, covering test plans, thread groups, assertions, listeners, timers, and distributed testing.
06-test
Write and iterate developer-side tests until they pass, or validate a user journey end to end in the browser during implementation. Use when the user wants to add coverage, find what's untested, or walk a flow while building it. Do NOT use for independent acceptance QA or reviewer evidence, auditing test health, or…
testing-patterns
Testing strategy: pyramid, AAA, mocks/fakes/stubs, flaky tests, coverage. Triggers: test, fixture, mock, stub, e2e, TDD, Playwright, Cypress, flaky, coverage, property-based.