Themis · unit / contract loop

Faster than Jest and Vitest. Built for AI agents.

  • 68.59% faster than Vitest, 130.26% faster than Jest on the same React benchmark.
  • Agent-native --agent JSON with failure clusters and structured repair hints.
  • One-command migration: npx themis migrate jest or vitest with codemods.
  • Modern by default: native .js, .jsx, .ts, .tsx, ESM, and React Testing Library.
  • Discoverable to agents: ships AGENTS.md, themis.ai.json manifest, and a Tessl tile.
npm install -D @vitronai/themis
GitHub → Tessl Registry →

The pair

Two layers. One agent loop.

Themis
Unit + contract layer.

The agent generates code, Themis verifies the contract in milliseconds, the agent iterates. Open source so it lives anywhere: local CI, sandbox, agent runtime.

Alethia
End-to-end + policy layer.

Once the unit tests pass, Alethia verifies the running app in-process, under EA1 policy, with a signed audit pack the agent can hand to a human reviewer.

Use Themis on its own. It's MIT and stands alone. Pair it with Alethia when you need deterministic browser-side verification inside the same loop.