[SaladDay]

Summary

Standalone, reusable Environments in the public Agents API. One Session attaches at a time, in sequence.

• Create POST /agents/environments:
  • Idempotency-Key takes 1–256 bytes; an empty key returns 400. A retry with the same key and body returns the same Environment, even after its named Template was deleted. A different body returns 409.
  • A non-empty vault_ids returns 400.
  • The Environment steps are shared with inline Session creation, so there is one preparation path.
• List GET /agents/environments returns the Project's standalone Environments with the official pagination.
• Retrieve: a prepared Environment with no attached Session reads ready.
• Attach is POST /agents/sessions with environment.environment_id:
  • The official not constraint applies, and so does the x_agents_core.environment rejection.
  • Status codes: 404 for a missing, foreign or reclaimed Environment; 409 when it is attached, failed or expired; attaching to a pending Environment is allowed.
  • If the Environment cannot reach the Session's model provider, the request returns 400 model_provider_unreachable (a recorded gap).
  • Two concurrent attaches produce exactly one winner.
• Detach: deleting the Session detaches it. The standalone Environment keeps its compute, workspace and preparation.
• Files on an unattached Environment return 409.
• Lifecycle model, one rule for every path:
  • one definition of ended and active, the environment_liveness view, read by every query that reclaims or admits;
  • one cleanup path: compute through the lifecycle reconcile on Allocation.Ended, placements through one sweep before reservation, workspaces through the deletion sweep;
  • one end rule: an unattached standalone Environment ends when it fails, a reset expires it, or its compute is released while no Session is attached.
• Idle timeout: idle_seconds is one top-level /core/v1 deployment setting for every Provider. With checkpoints an unattached Environment suspends after it and expires at the end of retention; without checkpoints it expires after it.
• Sealed preparation input is bound to the Environment.
• Automations: a target projects the stored environment_id.

Docs are in EN and zh: environments.md (new section "Standalone Environments"), index.md ledger, wire-semantics.md, environment-files.md, sandbox-deployment.md and public-agent-api.md, which gains a prewarm example.

Checks

• go vet ./..., scripts/check-sqlc.py, make openapi (no diff), pnpm --dir website check-translations and pnpm --dir website test pass.
• Tests pass with a database for api, sessions, deployment, deploymentpg, sessionpg, execution and tests/integration, including the official-SDK scenario (official_environments.py), concurrent attaches and creates, and the reset of an unattached Environment. The lifecycle tests fail when their rule is removed.
• Blind review: the final round, against the lifecycle model, found no lifecycle defect; its smaller findings are fixed.

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