Process isolation — remote execution, external comparison
Generated code runs in Nebius Sandbox, outside the website's control plane and the development machine. The comparison plan remains outside the candidate runtime.
The execution request supplies no inherited environment, requests disabled networking, and sets a 20-second runtime limit and 64 KiB limit per output stream.
Boundary: candidate and observation runner currently share a Python process inside Sandbox. Independent comparison is implemented; independently trusted observation is the next boundary to establish.
One correction. A finite repair protocol.
One initial proposal. At most one correction after a completed, bound failure. The same contract governs both attempts. A second failure terminates the loop; uncertain effects are not automatically repeated.
The application controls continuation, bounding iterative generation and token consumption. Attempt reservations constrain admission; they are not an account-wide billing guarantee.
Cryptographic binding. Evaluate the identified artifact.
SHA-256 digests identify the contract, proposal and uploaded files. Bundle snapshots, digest verification, upload byte counts and returned run identifiers reject payload changes and mismatched records at those checks.
A changed contract creates a different evaluation. Hash binding establishes artifact consistency; it does not authenticate candidate-reported behavior or attest execution.
Deterministic gates. Model confidence grants no authority.
Application code checks proposal schema, function name and signature, result structure and run binding. Incomplete, malformed or unbound execution results receive no passing verdict.
Passing declared checks permits review and export. Deployment remains a separate human decision.