LMArena made chat model quality visible. Embodied policies still live in private sims and PDF tables. You cannot open a URL, watch a stack fail, and read a public board. That gap is the product.
One task on purpose
VSArena is a stacking work-cell in the browser: a 4-DOF arm, a table, a pad, three cubes. Cyan base, orange middle, magenta on top. If people will not run this, they will not run a bigger suite. Studio v0.2.0 is one policy at a time. Arena 1v1 is on the roadmap, not in the claim.
Physics is Rapier WASM at 60 Hz inside Chrome. Teleop is keyboard. Baseline-IK and ColorSeek ship as demos so the cell is not empty. None of those demos write public ELO. That is intentional: the browser cannot be trusted to score itself.
Two observation tracks, one world
The VLA track is the public path. The agent receives 128×128 RGB and a language instruction. Cube poses are withheld on purpose — no GPS to the policy. Proprioception (joints and TCP) stays. The state track is privileged poses for Baseline-IK and debug; it is not the leaderboard path.
External agents speak WebSocket: hello → state → action → … → result. Scoring always uses privileged poses internally. The VLA track simply does not send them outbound. Spatial accuracy and task completion are computed in the harness; ELO moves only when ingest is authenticated with HARNESS_INGEST_SECRET.
Studio, harness, board
Studio is the watchable surface: orbit the camera, run ColorSeek, record a demo in the same VLA observation stream the harness uses (vsarena-demo-v1). Official live is a read-only spectator on the hosted harness. The Python SDK dry-runs offline and goes live against wss://vsarena-harness.onrender.com (or a local npm run harness).
The leaderboard is public ELO seeded from harness ingest, not from Studio clicks. GitHub OAuth unlocks an API key on /account. That separation — browser for presence, harness for truth — is the architecture, not a footnote.
Honest limits
This is not Isaac Sim. Not a paper suite. Not photorealistic Three.js camera feed for the policy — the MVP VLA raster is an orthographic work-cell. ColorSeek is a color-blob script, not a neural VLA. PyPI packaging and Arena head-to-head are still open. Say that first, or the rest is marketing.
MIT, Next.js 14, React Three Fiber, Rapier, Supabase, Python 3.11+. Live at vsarena.vercel.app. Cite: NovaCoding-G (2026). VSArena. v0.1.0. The file is CITATION.cff.
Studio demos do not write public ELO. Only harness ingest does.