Changelog

All notable changes to the OAC specification are documented here.

v1alpha3 — 2026-05-30

Inference type model requirements replaced with capability and performance requirements (§5.2). The inference.<type>.models label (a space-separated list of required model IDs) is removed. In its place, agents declare structured capability requirements — context (minimum context window in tokens), reasoning, tools, and input/output modality flags (input.vision, input.audio, input.video, output.image, output.audio, output.video) — and open-vocabulary benchmark minimums (bench.<id>). The orchestrator selects from its available models the best fit satisfying all declared requirements; deployment fails if no qualifying model exists.

Session isolation (session.isolation label, §5.7). Declares whether the harness handles multiple concurrent sessions in a single process. When "true", the orchestrator deploys the container as a long-running service; when absent or "false", one container instance is started per session.
Stream message schema (§4.5). A normative protobuf schema for the ConnectRPC stream between harness and orchestrator, with HarnessEnvelope, OrchestratorEnvelope, Event, SessionEnd, and EventResult messages.
session_id field on stream messages. Every message on the stream MUST carry a non-empty session_id. Harnessess declaring session.isolation="true" MUST demultiplex concurrent sessions using this field.
Workspace/session conflict error condition (§7.5). Orchestrators MUST fail deployment if session.isolation="true" and any workspace.* labels are declared together.
session label group added to the label group enumeration (§4.2).

Spec document version now aligned with label version. The document version and the org.openagentcontainers.version label value are the same identifier — there is no separate document versioning scheme (§8.2).
Label version updated from v1 to v1alpha2. The org.openagentcontainers.version label value now uses Kubernetes-style maturity stages to communicate spec stability. The progression is v1alpha1 → … → v1beta1 → … → v1 (stable/GA), with a new major version resuming at v2alpha1 (§8.1).
Orchestrator version acceptance rules. Orchestrators MUST NOT automatically accept a later alpha or beta revision — each accepted version must be explicitly declared.

Initial release.

OCI label namespace (org.openagentcontainers.*) and the explicit version label
Label groups: name, inference, mcp, workspace, orchestrator, events
Conformance classes: Producer, Orchestrator, Harness
Error handling requirements (§7): missing labels, model validation failure, missing schema files, unsatisfiable auth methods, unknown labels, unsupported spec version
Versioning and deprecation policy (§8)
Security considerations: artifact integrity, dependency trust, credential injection, agent identity
Operational considerations: observability, registry compatibility, Kubernetes deployment, registration-time performance
Appendix A examples: minimal artifact and full-featured artifact with MCP, workspace, and event subscription
Appendix B implementation notes: schema file extraction via crane, label parsing guidance