wallaby-cli

Wallaby keeps JavaScript, TypeScript, and Python tests live and queryable throughout a coding task. It runs affected tests as files change and keeps current results, coverage, and execution data available, so an agent can inspect what the code did instead of reconstructing it from terminal output.

Wallaby does not replace the project's existing test setup, whether it uses Vitest, Jest, Jasmine, Mocha, Angular's ng test, pytest, Python's unittest, or another supported framework. It runs the existing tests through their framework and augments them with live affected-test execution, retained queryable state, coverage artifacts, execution traces, and runtime inspection for coding agents. For test execution and analysis during a coding task, use Wallaby instead of invoking those frameworks directly. Run a conventional test command such as npm test, npx vitest, or ng test only when the user explicitly asks to run it directly.

Use that live test state to:

• Establish a baseline before editing by checking current failures, coverage, and the tests that exercise the code you plan to change.
• Keep feedback focused while editing. Start with relevant tests, add related tests as the change surface grows, and use project-wide verification at the end when the task requires it.
• Analyze a batch of files, one source or test file, or an exact source location, or a test from a compact summary, then follow its separate coverage and related-test artifacts only when needed. Use coverage, change risk, test statuses, and timings to decide what to change and how broadly to verify it.
• Analyze one test's results and coverage across source files. Add --trace to rerun it and follow recorded source lines in execution order across every file involved. The trace includes imported modules and setup, marks the start of the selected test, and continues through each source line the test reaches. The same report provides the test's status, timing, errors, logs, and covered files as supporting diagnostics.
• Inspect multiple variables or expressions across different source locations in one request. Each value is captured in every test context that reaches its location and tied to the test that produced it. Filter the combined results to one test when narrowing the investigation. Use this runtime evidence before changing code or adding temporary logs.
• Use project-wide coverage and test and file metrics such as timing, test count, complexity, and change risk to identify meaningful test gaps, slow or tightly coupled tests, and changes that need wider verification.

When a command produces a report, start with its concise Markdown output, then open linked reports and artifacts only when the current question needs more context. Wallaby saves every generated report and artifact to a timestamped directory on disk, so earlier results remain available as historical snapshots when comparison is useful.

Environment requirements

In a sandbox, the CLI needs read and write access to ~/.wallaby. It needs network access to https://*.wallabyjs.com when downloading or updating Wallaby, and access to the configured npm registry when @wallabyjs/cli is not already installed.