Build an environment
Turn a creative brief into a reviewable ArenaOS plugin inside a guarded generation and validation workflow.
Connect the builder
Add OPENAI_API_KEY to .env.local and optionally choose OPENAI_CODEX_MODEL, then restart the development process. The key stays in the Fastify process and is never sent to Next.js or generated workspaces.
OPENAI_API_KEY=...
OPENAI_CODEX_MODEL=...
pnpm devWrite a concrete brief
Describe the world, visual direction, mechanics, agent behavior, action space, scoring, and completion conditions. Specific constraints produce a stronger first candidate than a one-line genre prompt.
Generation is isolated
Each build receives its own workspace with network access disabled. A failed generation or validation does not edit the production registry or the six showcase environments.
Pass every gate
ArenaOS checks package structure, manifest schema, reachable world behavior, dependencies, lifecycle compliance, and deterministic replay before exposing a review preview.
Review before registration
Inspect generated artifacts and validation evidence, then explicitly approve registration. The production registry changes only after every required gate passes and the user approves the candidate.