npm run check for format/lint/type-check (not tests). Focused tests via vitest CLI from package root: cd packages/coding-agent && npx tsx ../../node_modules/vitest/dist/cli.js --run test/specific.test.ts. Suite tests (packages/coding-agent/test/suite/) use faux provider (test/suite/harness.ts) — no real APIs or paid tokens. Regressions named <issue-number>-<short-slug>.test.ts go under packages/coding-agent/test/suite/regressions/.
Always update .npmrc min-release-age=7 enforcement; override with --min-release-age=0 for urgent patches.
Related: Development workflow, Debugging