// Copyright 2026 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package google.cloud.geminidataanalytics.v1beta;

import "google/api/annotations.proto";
import "google/api/client.proto";
import "google/api/field_behavior.proto";
import "google/protobuf/struct.proto";
import "google/protobuf/timestamp.proto";

option csharp_namespace = "Google.Cloud.GeminiDataAnalytics.V1Beta";
option go_package = "cloud.google.com/go/geminidataanalytics/apiv1beta/geminidataanalyticspb;geminidataanalyticspb";
option java_multiple_files = true;
option java_outer_classname = "DataA2AServiceProto";
option java_package = "com.google.cloud.geminidataanalytics.v1beta";
option php_namespace = "Google\\Cloud\\GeminiDataAnalytics\\V1beta";
option ruby_package = "Google::Cloud::GeminiDataAnalytics::V1beta";

// DataA2AService defines the Agent-to-Agent (A2A) protocol service for Gemini
// Data Analytics.
service DataA2AService {
  option (google.api.default_host) = "geminidataanalytics.googleapis.com";
  option (google.api.oauth_scopes) =
      "https://www.googleapis.com/auth/cloud-platform";

  // Send a message to the agent. This is a blocking call that will return the
  // task once it is completed.
  rpc SendMessage(SendMessageRequest) returns (SendMessageResponse) {
    option (google.api.http) = {
      post: "/v1beta/a2a/{tenant=projects/*/locations/*/agents/*}/v1/message:send"
      body: "*"
      additional_bindings {
        post: "/v1beta/a2a/{tenant=projects/*/locations/*/dataAgents/*}/v1/message:send"
        body: "*"
      }
    };
    option (google.api.method_signature) = "tenant,message";
  }

  // SendStreamingMessage is a streaming call that will return a stream of
  // task update events until the Task is in an interrupted or terminal state.
  rpc SendStreamingMessage(SendMessageRequest) returns (stream StreamResponse) {
    option (google.api.http) = {
      post: "/v1beta/a2a/{tenant=projects/*/locations/*/agents/*}/v1/message:stream"
      body: "*"
      additional_bindings {
        post: "/v1beta/a2a/{tenant=projects/*/locations/*/dataAgents/*}/v1/message:stream"
        body: "*"
      }
    };
    option (google.api.method_signature) = "tenant,message";
  }

  // GetAgentCard returns the agent card for the agent.
  rpc GetAgentCard(GetAgentCardRequest) returns (AgentCard) {
    option (google.api.http) = {
      get: "/v1beta/a2a/{tenant=projects/*/locations/*/agents/*}/v1/card"
      additional_bindings {
        get: "/v1beta/a2a/{tenant=projects/*/locations/*/dataAgents/*}/v1/card"
      }
    };
    option (google.api.method_signature) = "tenant";
  }
}

// The set of states a Task can be in.
enum TaskState {
  // Default unspecified task state.
  TASK_STATE_UNSPECIFIED = 0;

  // Represents the status that acknowledges a task is created.
  TASK_STATE_SUBMITTED = 1;

  // Represents the status that a task is currently in progress.
  TASK_STATE_WORKING = 2;

  // Represents the status that a task is completed. This is a terminal state.
  TASK_STATE_COMPLETED = 3;

  // Represents the status that a task has failed. This is a terminal state.
  TASK_STATE_FAILED = 4;

  // Represents the status that a task was cancelled before it finished.
  // This is a terminal state.
  TASK_STATE_CANCELLED = 5;

  // Represents the status that the task requires information to complete.
  // This is an interrupted state.
  TASK_STATE_INPUT_REQUIRED = 6;

  // Represents the status that a task has been rejected by the agent.
  // This is a terminal state.
  TASK_STATE_REJECTED = 7;

  // Represents the state that some authentication is needed from the upstream
  // client.
  TASK_STATE_AUTH_REQUIRED = 8;
}

// Role indicates the sender of a message.
enum Role {
  // Default unspecified role.
  ROLE_UNSPECIFIED = 0;

  // USER role refers to communication from the client to the server.
  ROLE_USER = 1;

  // AGENT role refers to communication from the server to the client.
  ROLE_AGENT = 2;
}

// Configuration of a send message request.
message SendMessageConfiguration {
  // Optional. The output modes that the agent is expected to respond with.
  repeated string accepted_output_modes = 1
      [(google.api.field_behavior) = OPTIONAL];

  // Optional. A configuration of a webhook that can be used to receive updates.
  PushNotificationConfig push_notification = 2
      [(google.api.field_behavior) = OPTIONAL];

  // Optional. The maximum number of messages to include in the history. If 0,
  // the history will be unlimited.
  int32 history_length = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. If true, the message will be blocking until the task is
  // completed. If false, the task will be returned immediately.
  bool blocking = 4 [(google.api.field_behavior) = OPTIONAL];
}

// A2ATask is the core unit of action for A2A. It has a current status
// and when results are created for the task they are stored in the
// artifact. If there are multiple turns for a task, these are stored in
// history.
message A2ATask {
  // Optional. Unique identifier (e.g. UUID) for the task, generated by the
  // server for a new task.
  string id = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Unique identifier (e.g. UUID) for the contextual collection of
  // interactions (tasks and messages). Created by the A2A server.
  string context_id = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The current status of a Task, including state and a message.
  TaskStatus status = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A set of output artifacts for a Task.
  repeated A2AArtifact artifacts = 4 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The history of interactions from a task.
  repeated A2AMessage history = 5 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A key/value object to store custom metadata about a task.
  google.protobuf.Struct metadata = 6 [(google.api.field_behavior) = OPTIONAL];
}

// A container for the status of a task.
message TaskStatus {
  // Output only. The current state of this task.
  TaskState state = 1 [(google.api.field_behavior) = OUTPUT_ONLY];

  // Optional. A message associated with the status.
  A2AMessage update = 2
      [json_name = "message", (google.api.field_behavior) = OPTIONAL];

  // Output only. Timestamp when the status was recorded.
  google.protobuf.Timestamp timestamp = 3
      [(google.api.field_behavior) = OUTPUT_ONLY];
}

// Part represents a container for a section of communication content.
// Parts can be purely textual, some sort of file (image, video, etc) or
// a structured data blob (i.e. JSON).
message Part {
  // The content payload of the part.
  oneof part {
    // Plain text content.
    string text = 1;

    // File content payload.
    FilePart file = 2;

    // Structured data content payload.
    DataPart data = 3;
  }

  // Optional. Metadata associated with the part.
  google.protobuf.Struct metadata = 4 [(google.api.field_behavior) = OPTIONAL];
}

// FilePart represents the different ways files can be provided.
message FilePart {
  // The file representation payload.
  oneof file {
    // The URI pointing to the file.
    string file_with_uri = 1;

    // The raw bytes of the file.
    bytes file_with_bytes = 2;
  }

  // Optional. The MIME type of the file.
  string mime_type = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The name of the file.
  string name = 4 [(google.api.field_behavior) = OPTIONAL];
}

// DataPart represents a structured blob. This is most commonly a JSON payload.
message DataPart {
  // Optional. The structured data payload.
  google.protobuf.Struct data = 1 [(google.api.field_behavior) = OPTIONAL];
}

// A2AMessage is one unit of communication between client and server.
message A2AMessage {
  // Optional. The unique identifier (e.g. UUID) of the message.
  string message_id = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The context id of the message.
  string context_id = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The task id of the message.
  string task_id = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A role for the message.
  Role role = 4 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Content is the container of the message content.
  repeated Part content = 5 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Any optional metadata to provide along with the message.
  google.protobuf.Struct metadata = 6 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The URIs of extensions that are present or contributed to this
  // Message.
  repeated string extensions = 7 [(google.api.field_behavior) = OPTIONAL];
}

// A2AArtifact is the container for task completed results.
message A2AArtifact {
  // Optional. Unique identifier (e.g. UUID) for the artifact.
  string artifact_id = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A human readable name for the artifact.
  string name = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A human readable description of the artifact, optional.
  string description = 4 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The content of the artifact.
  repeated Part parts = 5 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Optional metadata included with the artifact.
  google.protobuf.Struct metadata = 6 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The URIs of extensions that are present or contributed to this
  // Artifact.
  repeated string extensions = 7 [(google.api.field_behavior) = OPTIONAL];
}

// TaskStatusUpdateEvent is a delta event on a task indicating that a task
// has changed.
message TaskStatusUpdateEvent {
  // Optional. The id of the task that is changed.
  string task_id = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The id of the context that the task belongs to.
  string context_id = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The new status of the task.
  TaskStatus status = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Whether this is the last status update expected for this task.
  bool final = 4 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Optional metadata to associate with the task update.
  google.protobuf.Struct metadata = 5 [(google.api.field_behavior) = OPTIONAL];
}

// TaskArtifactUpdateEvent represents a task delta where an artifact has
// been generated.
message TaskArtifactUpdateEvent {
  // Optional. The id of the task for this artifact.
  string task_id = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The id of the context that this task belongs to.
  string context_id = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The artifact itself.
  A2AArtifact artifact = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Whether this should be appended to a prior one produced.
  bool append = 4 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Whether this represents the last part of an artifact.
  bool last_chunk = 5 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Optional metadata associated with the artifact update.
  google.protobuf.Struct metadata = 6 [(google.api.field_behavior) = OPTIONAL];
}

// Configuration for setting up push notifications for task updates.
message PushNotificationConfig {
  // Optional. A unique identifier (e.g. UUID) for this push notification.
  string id = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Url to send the notification to.
  string url = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Token unique for this task/session.
  string token = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Information about the authentication to send with the
  // notification.
  AuthenticationInfo authentication = 4
      [(google.api.field_behavior) = OPTIONAL];
}

// Defines authentication details, used for push notifications.
message AuthenticationInfo {
  // Optional. Supported authentication schemes - e.g. Basic, Bearer, etc.
  repeated string schemes = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Optional credentials.
  string credentials = 2 [(google.api.field_behavior) = OPTIONAL];
}

// Defines additional transport information for the agent.
message AgentInterface {
  // Optional. The url this interface is found at.
  string url = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The transport supported at this url.
  string transport = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Tenant to be set in the request when calling the agent.
  string tenant = 3 [(google.api.field_behavior) = OPTIONAL];
}

// AgentCard conveys key information about an agent.
message AgentCard {
  // Optional. The version of the A2A protocol this agent supports.
  string protocol_version = 16 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A human readable name for the agent.
  string name = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A description of the agent's domain of action/solution space.
  string description = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A URL to the address the agent is hosted at.
  string url = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The transport of the preferred endpoint. If empty, defaults to
  // JSONRPC.
  string preferred_transport = 14 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Announcement of additional supported transports.
  repeated AgentInterface additional_interfaces = 15
      [(google.api.field_behavior) = OPTIONAL];

  // Optional. The service provider of the agent.
  AgentProvider provider = 4 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The version of the agent.
  string version = 5 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A url to provide additional documentation about the agent.
  string documentation_url = 6 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A2A Capability set supported by the agent.
  AgentCapabilities capabilities = 7 [(google.api.field_behavior) = OPTIONAL];

  // The security scheme details used for authenticating with this agent.
  map<string, SecurityScheme> security_schemes = 8;

  // Security requirements for contacting the agent.
  repeated Security security = 9;

  // Optional. The set of interaction modes that the agent supports across all
  // skills.
  repeated string default_input_modes = 10
      [(google.api.field_behavior) = OPTIONAL];

  // Optional. The mime types supported as outputs from this agent.
  repeated string default_output_modes = 11
      [(google.api.field_behavior) = OPTIONAL];

  // Optional. Skills represent a unit of ability an agent can perform.
  repeated AgentSkill skills = 12 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Whether the agent supports providing an extended agent card when
  // the user is authenticated.
  bool supports_authenticated_extended_card = 13
      [(google.api.field_behavior) = OPTIONAL];

  // Optional. JSON Web Signatures computed for this AgentCard.
  repeated AgentCardSignature signatures = 17
      [(google.api.field_behavior) = OPTIONAL];

  // Optional. An optional URL to an icon for the agent.
  string icon_url = 18 [(google.api.field_behavior) = OPTIONAL];
}

// Represents information about the service provider of an agent.
message AgentProvider {
  // Optional. The provider's reference url.
  string url = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The provider's organization name.
  string organization = 2 [(google.api.field_behavior) = OPTIONAL];
}

// Defines the A2A feature set supported by the agent.
message AgentCapabilities {
  // Optional. If the agent will support streaming responses.
  bool streaming = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. If the agent can send push notifications to the client's webhook.
  bool push_notifications = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Extensions supported by this agent.
  repeated AgentExtension extensions = 3
      [(google.api.field_behavior) = OPTIONAL];
}

// A declaration of an extension supported by an Agent.
message AgentExtension {
  // Optional. The URI of the extension.
  string uri = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A description of how this agent uses this extension.
  string description = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Whether the client must follow specific requirements of the
  // extension.
  bool required = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Optional configuration for the extension.
  google.protobuf.Struct params = 4 [(google.api.field_behavior) = OPTIONAL];
}

// AgentSkill represents a unit of action/solution that the agent can perform.
message AgentSkill {
  // Optional. Unique identifier of the skill within this agent.
  string id = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A human readable name for the skill.
  string name = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A human readable description of the skill details and behaviors.
  string description = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A set of tags for the skill to enhance
  // categorization/utilization.
  repeated string tags = 4 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A set of example queries that this skill is designed to address.
  repeated string examples = 5 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Possible input modalities supported.
  repeated string input_modes = 6 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Possible output modalities produced.
  repeated string output_modes = 7 [(google.api.field_behavior) = OPTIONAL];

  // Security schemes necessary for the agent to leverage this skill.
  repeated Security security = 8;
}

// AgentCardSignature represents a JWS signature of an AgentCard.
message AgentCardSignature {
  // Required. The protected JWS header for the signature. Base64url-encoded.
  string protected = 1 [(google.api.field_behavior) = REQUIRED];

  // Required. The computed signature, base64url-encoded.
  string signature = 2 [(google.api.field_behavior) = REQUIRED];

  // Optional. The unprotected JWS header values.
  google.protobuf.Struct header = 3 [(google.api.field_behavior) = OPTIONAL];
}

// StringList is a wrapper for a repeated list of strings.
message StringList {
  // The list of strings.
  repeated string list = 1;
}

// Security requirements for contacting the agent.
message Security {
  // Map of scheme names to lists of scopes or configurations.
  map<string, StringList> schemes = 1;
}

// SecurityScheme defines a security scheme for contacting the agent.
message SecurityScheme {
  // The security scheme definition.
  oneof scheme {
    // API key security scheme.
    APIKeySecurityScheme api_key_security_scheme = 1;

    // HTTP authentication security scheme.
    HTTPAuthSecurityScheme http_auth_security_scheme = 2;

    // OAuth2 security scheme.
    OAuth2SecurityScheme oauth2_security_scheme = 3;

    // OpenID Connect security scheme.
    OpenIdConnectSecurityScheme open_id_connect_security_scheme = 4;

    // Mutual TLS security scheme.
    MutualTlsSecurityScheme mtls_security_scheme = 5;
  }
}

// APIKeySecurityScheme defines an API key security scheme.
message APIKeySecurityScheme {
  // Optional. Description of this security scheme.
  string description = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Location of the API key, valid values are "query", "header", or
  // "cookie".
  string location = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Name of the header, query or cookie parameter to be used.
  string name = 3 [(google.api.field_behavior) = OPTIONAL];
}

// HTTPAuthSecurityScheme defines an HTTP authentication security scheme.
message HTTPAuthSecurityScheme {
  // Optional. Description of this security scheme.
  string description = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The name of the HTTP Authentication scheme to be used in the
  // Authorization header.
  string scheme = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. A hint to the client to identify how the bearer token is
  // formatted.
  string bearer_format = 3 [(google.api.field_behavior) = OPTIONAL];
}

// OAuth2SecurityScheme defines an OAuth2 security scheme.
message OAuth2SecurityScheme {
  // Optional. Description of this security scheme.
  string description = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. An object containing configuration information for the flow types
  // supported.
  OAuthFlows flows = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. URL to the oauth2 authorization server metadata.
  string oauth2_metadata_url = 3 [(google.api.field_behavior) = OPTIONAL];
}

// OpenIdConnectSecurityScheme defines an OpenID Connect security scheme.
message OpenIdConnectSecurityScheme {
  // Optional. Description of this security scheme.
  string description = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Well-known URL to discover the OpenID Connect provider metadata.
  string open_id_connect_url = 2 [(google.api.field_behavior) = OPTIONAL];
}

// MutualTlsSecurityScheme defines a Mutual TLS security scheme.
message MutualTlsSecurityScheme {
  // Optional. Description of this security scheme.
  string description = 1 [(google.api.field_behavior) = OPTIONAL];
}

// OAuthFlows contains configuration information for supported OAuth flows.
message OAuthFlows {
  // The supported OAuth flow configuration.
  oneof flow {
    // Authorization code flow.
    AuthorizationCodeOAuthFlow authorization_code = 1;

    // Client credentials flow.
    ClientCredentialsOAuthFlow client_credentials = 2;

    // Implicit flow.
    ImplicitOAuthFlow implicit = 3;

    // Resource owner password credentials flow.
    PasswordOAuthFlow password = 4;
  }
}

// AuthorizationCodeOAuthFlow defines an authorization code OAuth flow.
message AuthorizationCodeOAuthFlow {
  // Optional. The authorization URL to be used for this flow.
  string authorization_url = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The token URL to be used for this flow.
  string token_url = 2 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The URL to be used for obtaining refresh tokens.
  string refresh_url = 3 [(google.api.field_behavior) = OPTIONAL];

  // The available scopes for the OAuth2 security scheme.
  map<string, string> scopes = 4;
}

// ClientCredentialsOAuthFlow defines a client credentials OAuth flow.
message ClientCredentialsOAuthFlow {
  // Optional. The token URL to be used for this flow.
  string token_url = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The URL to be used for obtaining refresh tokens.
  string refresh_url = 2 [(google.api.field_behavior) = OPTIONAL];

  // The available scopes for the OAuth2 security scheme.
  map<string, string> scopes = 3;
}

// ImplicitOAuthFlow defines an implicit OAuth flow.
message ImplicitOAuthFlow {
  // Optional. The authorization URL to be used for this flow.
  string authorization_url = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The URL to be used for obtaining refresh tokens.
  string refresh_url = 2 [(google.api.field_behavior) = OPTIONAL];

  // The available scopes for the OAuth2 security scheme.
  map<string, string> scopes = 3;
}

// PasswordOAuthFlow defines a password OAuth flow.
message PasswordOAuthFlow {
  // Optional. The token URL to be used for this flow.
  string token_url = 1 [(google.api.field_behavior) = OPTIONAL];

  // Optional. The URL to be used for obtaining refresh tokens.
  string refresh_url = 2 [(google.api.field_behavior) = OPTIONAL];

  // The available scopes for the OAuth2 security scheme.
  map<string, string> scopes = 3;
}

// Request message for SendMessage and SendStreamingMessage.
message SendMessageRequest {
  // Required. The message to send to the agent.
  A2AMessage message = 1 [(google.api.field_behavior) = REQUIRED];

  // Optional. Configuration for the send request.
  SendMessageConfiguration configuration = 2
      [(google.api.field_behavior) = OPTIONAL];

  // Optional. Optional metadata for the request.
  google.protobuf.Struct metadata = 3 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Optional tenant, provided as a path parameter.
  string tenant = 4 [(google.api.field_behavior) = OPTIONAL];
}

// Request message for GetAgentCard.
message GetAgentCardRequest {
  // Optional. Optional tenant, provided as a path parameter.
  string tenant = 1 [(google.api.field_behavior) = OPTIONAL];
}

// Response message for SendMessage.
message SendMessageResponse {
  // The response payload.
  oneof payload {
    // Completed task.
    A2ATask task = 1;

    // Single message response.
    A2AMessage msg = 2 [json_name = "message"];
  }
}

// The stream response for a message.
message StreamResponse {
  // The stream response payload.
  oneof payload {
    // Completed task event.
    A2ATask task = 1;

    // Message event.
    A2AMessage msg = 2 [json_name = "message"];

    // Task status update event.
    TaskStatusUpdateEvent status_update = 3;

    // Task artifact update event.
    TaskArtifactUpdateEvent artifact_update = 4;
  }
}