UNMAPPED markers

The specification marks with UNMAPPED each rule of A2A it does not hold, in a YAML comment beside the place the rule belongs. ess/ has 41 markers: 40 name a construct ESS lacks (an ESS gap), 1 an open question. Each row links the marker's line and shows its first sentence; the comment there carries the source quote and, for an ESS gap, the refusal ESS gave.

The HTTP+JSON routes ESS cannot serve at A2A's path are on HTTP+JSON routes.

ess/components.yaml

Line	Kind	Marker
10	ESS gap	the binding itself. ESS 0.67.0 binds a command to an HTTP route (ess-http/1), one method and path each, while JSON-RPC sends every method to one endpoint and dispatches on the body's method.
33	ESS gap	no authored scenario holds -32601 or -32602. An act expects one refusal, refused: not_granted; there is none for an input the declaration rejects or for an unknown command, and a scenario naming an undeclared command is refused by name.
59	ESS gap	push delivery. Section 4.3.3: "When a task update occurs, the agent sends an HTTP POST request to the configured webhook URL", and the same section: "Agents MUST attempt delivery at least once for each configured webhook".
74	ESS gap	the stream transport. Section 11.7: "REST streaming uses Server-Sent Events", answering Content-Type: text/event-stream with one data: line per StreamResponse; JSON-RPC streams over SSE too (section 9.4.2), gRPC as a server stream (10.7).

ess/domains/discovery.yaml

Line	Kind	Marker
229	ESS gap	the exactly-one rule of the oneof. ESS 0.67.0 has no externally tagged union (a union without tag: is refused: "missing field tag").
292	ESS gap	the exactly-one rule of the oneof, as for OAuthFlows above.

ess/domains/tasks.yaml

Line	Kind	Marker
58	ESS gap	the exactly-one rule. ESS 0.67.0 validates it as a type invariant (any: [all: [defined(text), not defined(raw), …], …]), but Part is reachable from the typed responses of GetTask, CancelTask, SubscribeToTask and SendMessage, and synthesis then refuses each returning outcome: "ESS-SYNTH-001: … …
120	ESS gap	a2a.proto, Artifact.artifact_id: "It must be unique within a task", and Artifact.parts: "Must contain at least one part." The second validates as a type invariant (parts.count >= 1), but synthesis refuses it: "record invariant on a response type a2a.tasks.Artifact has no executable observer".
363	ESS gap	the natural identity is the struct (task_id, config_id). ESS 0.67.0 refuses both ways to create one: instance: {task_id: input.task_id, id: input.id} gives "invalid type: map, expected a string", and a struct identity published by the creating event gives SYNTH-001 "a struct held by reference has …
404	ESS gap	the per-row boundary (which tasks and configurations this client may see); ESS 0.67.0 grants a whole view to an actor.
428	ESS gap	the summary is the only place ESS 0.67.0 carries the code, and nothing reads it.
579	ESS gap	ESS 0.67.0 answers a command when its outcome commits. Missing construct: an answer deferred until later commands (StartWorking, Complete, RequireInput, …) move the created row into a named set of states.
604	ESS gap	task-not-found, task-terminal, context-mismatch and continued depend on message.taskId, a member of the message input.
656	ESS gap	a2a.proto, SendMessageConfiguration.task_push_notification_config: "Configuration for the agent to send push notifications for task updates.
714	ESS gap	task-not-found, task-terminal, context-mismatch and continued depend on message.taskId, a member of the message input.
785	ESS gap	a2a.proto, SendMessageConfiguration.task_push_notification_config: "Configuration for the agent to send push notifications for task updates.
826	ESS gap	a2a.proto, GetTaskRequest.history_length: "The server MUST NOT return more messages than the provided value, but MAY apply a lower limit." Nothing below bounds the returned task.history by it.
984	ESS gap	nothing emits a2a.tasks.TaskSubscriptionResponse. Subscribing changes no task, and a preserving outcome that emits is refused: "ESS-COMMAND-004: a preserving outcome declares no assignment, event or error".
1025	open question	A2A v1.0.1 is silent on a second create with an id a configuration of the same task already carries; created then adds a second row with that pair.
1029	ESS gap	assigned writes row and config_id as two independent {generated: true} values; ESS 0.67.0 has no construct to generate the id once and reuse it in the stored field and the event payload, so nothing checks they agree.
1057	ESS gap	a task of another tenant, or of one when the request has none (and the reverse), answers TaskNotFound, as GetTask other-tenant says.
1150	ESS gap	the rule is on the configuration's tenant, not the task's. ESS 0.67.0 refuses a when_subject: guard beside this row-set guard: "ESS-COMMAND-009: a2a.tasks.GetTaskPushNotificationConfig selects on a row set (when_related: {entity, where, …}) and on a when_subject guard; one command reads one …
1161	ESS gap	the config answered is not bound to the matched row; a typed response is opaque to ESS 0.67.0, as on ListTaskPushNotificationConfigs.
1200	ESS gap	which rows configs holds. Section 3.1.9: "The operation MUST return all active push notification configurations for the specified task and MAY support pagination".
1275	ESS gap	a task of another tenant, or of one when the request has none (and the reverse), answers TaskNotFound, as GetTask other-tenant says.
1283	ESS gap	a no-op delete emits PushNotificationConfigDeleted; a separate no-op branch (when_related exists: false) is refused, ESS-SYNTH-001 "a step of the scenario changes rows of the selector's entity in a way synthesis does not follow".
1374	ESS gap	section 7.6.1, the agent "MUST include a TaskStatus message explaining the required authorization, unless the details of the authorization have been negotiated out-of-band or via an extension".
1525	ESS gap	the task's stored artifacts should gain input.artifact, or, with append, the parts of the artifact with the same artifact_id should grow (a2a.proto, TaskArtifactUpdateEvent.append: "the content of this artifact should be appended to a previously sent artifact with the same ID").
1596	ESS gap	the exactly-one rule of the oneof. ESS 0.67.0 has no externally tagged union (a union without tag: is refused: "missing field tag"), and an emitting outcome must source every member, the absent ones included: leaving message out of the payload is refused, "ESS-COMMAND-005: emitted payload …
1605	ESS gap	the elements after the first. Section 3.1.2 follows the first Task with "zero or more TaskStatusUpdateEvent or TaskArtifactUpdateEvent objects", and section 3.5.2: "Events MUST be broadcast to all active streams for that task" and "Each stream MUST receive the same events in the same order".
1663	ESS gap	row has no A2A source; dropping it is refused, ESS-COMMAND-001 "acts on the instance named by row, which is no field of an emitted event of it".
1683	ESS gap	"Implementations MUST return tasks sorted by their status timestamp time in descending order".
1689	ESS gap	the cursor paging (page_size, page_token, next_page_token, "MUST use cursor-based pagination").
1698	ESS gap	a view answers no error, so the protocol-negotiation refusals (VersionNotSupportedError -32009, ExtensionSupportRequiredError -32008; section 3.6.2 "agents MUST return a VersionNotSupportedError") are not declared for ListTasks.
1711	ESS gap	wire type is TaskState (TASK_STATE_*); ESS 0.67.0 has no map from it to the lifecycle states the filter compares.
1742	ESS gap	the wire spells the state TASK_STATE_*. ESS 0.67.0 gives a lifecycle state no wire spelling: states: [{name: Submitted, wire: TASK_STATE_SUBMITTED}, …] is refused "invalid type: map, expected a string", so the row carries the lifecycle name.
1766	ESS gap	the per-row boundary within the Agent's reads (which tasks one authenticated caller may see); ESS 0.67.0 grants a whole view to an actor, no subset of rows.
1840	ESS gap	row has no A2A source; dropping it is refused, ESS-SYNTH-001 on DeleteTaskPushNotificationConfig/deleted "published by no immediate, unfiltered, unparameterised, unpaged view carrying its identity".

ess/http.yaml

Line	Kind	Marker
8	ESS gap	the /{tenant}/... additional binding of every operation, for example post: "/{tenant}/message:send" beside post: "/message:send".
31	ESS gap	DELETE carries its inputs outside the path in a JSON body, where section 11.5 says "HTTP methods that do not support request bodies (GET, DELETE) MUST transmit operation request parameters as path parameters or query parameters": query encoding is admitted on get only (ESS-HTTP-020).
56	ESS gap	a2a.proto CancelTask, post "/tasks/{id=*}:cancel", body "*", and SubscribeToTask, get "/tasks/{id=*}:subscribe" (section 11.3.2 writes POST /tasks/{id}:subscribe), keep their derived routes, post /tasks/commands/tasks:cancel and post /tasks/commands/tasks:subscribe.