Vitest runner

Run existing Vitest tests and report results. A check-only request does not authorize changing tests, assertions, dependencies, or configuration.

Run

Read repository instructions and package scripts. Check package.json, vitest.config.*, and vite.config.* to confirm Vitest and its test configuration. Use the installed project version; avoid implicit npx downloads. If Vitest is unavailable, report setup needed rather than installing it.

Use the repository test command or these defaults. Always use run; bare vitest can enter watch mode.

Scope	Command
Whole configured suite	npx vitest run --reporter=verbose 2>&1
File or directory	npx vitest run path/to/test.ts 2>&1
Test-name pattern	npx vitest run -t "pattern" 2>&1
Requested coverage	npx vitest run --coverage 2>&1

Capture the process exit code and full output. Report pass/fail, checked scope, passed/failed/skipped counts, and duration. For failures retain the file, full test name, assertion difference, and relevant stack location. Keep complete logs available; show useful excerpts instead of every passing test. Nonzero exit is failure, including discovery or tool failures; partial output is not a passing run.

Recovery

• Vitest missing/node_modules absent: inspect dependencies. Setup may require npm install or npm install -D vitest; use the repository package manager during authorized setup.
• No test files: check file naming (*.test.ts, *.spec.ts, *.test.js) and configured include/exclude globs. Report discovery failure; do not change config to mask it.
• Missing DOM environment: inspect environment for jsdom or happy-dom. Suggest the matching devDependency (npm install -D jsdom or npm install -D happy-dom); @testing-library/jest-dom adds matchers, not an environment.
• Out of memory: diagnose with directory batches such as npx vitest run src/unit/, --pool=forks, or --shard=1/N when supported by the installed version. A full-suite claim requires all batches/shards; a diagnostic subset is not full verification.
• Failing assertions: report the mismatch. When fixing is authorized, determine whether implementation or test is wrong; never weaken assertions merely to make the run green.