swift-testing-pro: Helping Coding Assistants Write Better Tests with Swift Testing

Who It Is For

swift-testing-pro is for people who are writing tests with Swift Testing and want a coding assistant to add tests according to those conventions. The official page names Claude Code, Codex, Cursor, and Gemini, while using "like" to indicate that similar tools are included as well, so do not read this list as an exclusive allowlist. It is not an XCTest migration guide, nor is it a standalone test-running app.

A better starting point is to have Node already installed on the machine (so that npx works), an existing project that uses Swift Testing, and a willingness to review suggestions before asking the assistant to change test files. If npx is unavailable, the official page explicitly says that Node has not been installed yet. The benefit is limited for people who only want to write tests by hand or do not plan to install the skill for their assistant. The page does not specify a required Swift or Xcode version.

A First Attempt in 3 Minutes

Prerequisites: Node is installed and the current project can use Swift Testing. The official installation for all supported agents uses only this command; do not present other entry points alongside it:

npx skills add https://github.com/twostraws/swift-testing-agent-skill --skill swift-testing-pro

This command installs swift-testing-pro in a skill location that the current agent can read. If npx: command not found appears, install Node first; do not switch to an unverified alternative command.

After installation, start with a request that can be checked: ask the assistant to use swift-testing-pro to inspect the existing tests and only point out where Swift Testing could improve them; do not change files yet. Writing tests is an operation with side effects, so allow it to write to disk only after you confirm the suggestions. In Claude Code, the official trigger syntax is /swift-testing-pro; the other named agents invoke the same skill name through their own skill-trigger mechanism.

A success signal is that the assistant discusses Swift Testing tests through this skill and does not change the repository before you approve. The official page provides no example test code, required APIs, or pass criteria; the evidence goes only as far as "helping write better Swift Testing tests".

Reference page: https://github.com/twostraws/swift-testing-agent-skill

Use Cases

Case one: ask the skill to improve Swift Testing tests. The official capability is to help a coding assistant write better tests with Swift Testing. Point it to an existing test file or type, request analysis and suggestions only at first, and then decide whether to write the changes. Do not ask it to invent assertion APIs that do not appear on this page. If the project still uses another testing framework, the page gives no migration steps; the evidence stops at Swift Testing.

Case two: trigger it with a slash command in Claude Code. The official trigger is /swift-testing-pro. After installation, enter this command and run a read-only comparison against the currently open test or type to confirm that Claude Code recognizes the skill. This is not a second installation path, only a trigger method. The page does not list parameters for the slash command; when there are no parameters, append one sentence describing the target to inspect.

Usage Boundaries

The capability stops at "writing better tests with Swift Testing". For a first installation, accept only the npx skills add command above. Claude Code, Codex, Cursor, and Gemini are named examples, not a closed allowlist. Without Node there is no npx; the official page explains npx: command not found as meaning that Node is not installed. The page also offers a Claude Code marketplace installation, but do not use that route for the first attempt, to avoid presenting two primary paths side by side. Confirm before writing tests. No uninstall instructions, XCTest comparison table, or minimum system version is provided.