Protobuf is the source of truth for the agent contract; transports are thin callers of the domain

(PR #9, ADR-0021; maintainer ruling). The decision that the REST/JSON surface is generated from the protobuf definitions is narrowed to the agent contract: protobuf remains the source of truth for everything agents and the control plane exchange, and the human surface is hand-shaped HTTP handlers over the shared domain layer instead of a generated façade. The reason is that the operator-surface semantics settled in the M3 design (browser sessions and cookies, problem documents, conditional requests, blast-radius guards) are properties of the transport that a generated façade cannot express, and expressing them around a generator costs more than writing the handlers. Drift protection moves from a shared schema to shared domain functions: the command line and the surface call the same functions, and a handler that holds domain logic is the reviewable defect. The principle that the console uses only the public surface carries into ADR-0021 unchanged, where decision 1 states it for the surface's own record. The surface design rules bullet is corrected in the same ruling: the earlier text mandated bulk endpoints, cursor pagination everywhere, and an asynchronous job pattern in which a fan-out mutation returns a job identifier, which contradicts the settled M3 design; the bulk mode change returns a recorded intent with no job resource and convergence is observed through the read model (applied against latest), generic bulk operations are out of version 1, and aggregate reads return bounded rollups computed server-side. The decision and consequence bullets are corrected in place; prior text is in git history. On the adr-review finding that this reversal called for supersession, the maintainer ruled that the record's core survives (one source of truth per contract; the transports are thin callers of it) and that amendment in place is the mechanism, as it was for ADR-0002 and ADR-0009; the earlier ruling's word "superseded" was loose language for the replacement of one clause, and a separate record would only restate ADR-0021 decision 5. The two specific points the finding raised are fixed here: the title is corrected from "Protobuf is the API source of truth; gRPC for agents, REST/JSON façade for everyone else" to the current one, since a title, like a body, states the current decision and the number is the permanent citation key (docs/adr/README.md); and the mechanics are stated in this note rather than left to the ruling's wording.

(PR #25, conformance-audit absorption). The core decision stands. The surface design rule that unbounded reads paginate by cursor gains a recorded exception, because the shipped surface returns five collections whole: rulesets, services, address groups, provisioning tokens, and operator tokens. They are configuration an operator authors by hand, bounded in practice by that authoring, and the contract describes them as complete lists; the reads that grow with an estate (workloads, flow windows, rollups, gaps) are paginated or bounded as the rule requires. Cursor pagination for the configuration collections is recorded backlog, to be taken before any of them could grow past a single response.