syntax = "proto3";

package codex.code_mode.v1;

// Hosts stateful JavaScript execution and delegates nested tool calls to the
// session owner. Large tool inputs and outputs stay off the session event
// stream so independent HTTP/2 streams can make progress concurrently.
service CodeModeHost {
  // Opens a session lease. The first event is always SessionOpened; dropping
  // this stream closes the session and terminates its active cells.
  rpc OpenSession(OpenSessionRequest) returns (stream SessionEvent);
  rpc CloseSession(CloseSessionRequest) returns (CloseSessionResponse);

  // Each subscription owns an independent stream of matching invocations. An
  // empty tool_names filter matches every tool. Each invocation is routed to
  // exactly one matching subscription, even when filters overlap.
  rpc SubscribeToToolCalls(SubscribeToToolCallsRequest)
      returns (stream ToolCall);

  // Each result receives its own HTTP/2 stream, preventing a large response
  // from blocking unrelated tool completions or session control events.
  rpc CompleteToolCall(CompleteToolCallRequest)
      returns (CompleteToolCallResponse);
  rpc AcknowledgeNotification(AcknowledgeNotificationRequest)
      returns (AcknowledgeNotificationResponse);

  // Emits ExecutionStarted immediately, followed by one ExecutionOutcome when
  // the execution yields, completes, or is terminated.
  rpc Execute(ExecuteRequest) returns (stream ExecuteEvent);
  rpc Wait(WaitRequest) returns (WaitResponse);

  // Acknowledges that a canceled wait has retired before another wait starts.
  rpc CancelWait(CancelWaitRequest) returns (CancelWaitResponse);
  rpc Terminate(TerminateRequest) returns (WaitResponse);
}

message OpenSessionRequest {
  optional SessionCellExecutionLimits cell_execution_limits = 1;
}

message SessionCellExecutionLimits {
  optional uint64 max_yield_time_ms = 1;
  optional uint64 max_heap_size_bytes = 2;
}

message SessionEvent {
  oneof event {
    SessionOpened opened = 1;
    ToolCallCancelled tool_call_cancelled = 2;
    Notification notification = 3;
    NotificationCancelled notification_cancelled = 4;
    CellClosed cell_closed = 5;
  }
}

message SessionOpened {
  string session_id = 1;
}

message CloseSessionRequest {
  string session_id = 1;
}

message CloseSessionResponse {}

message SubscribeToToolCallsRequest {
  string session_id = 1;
  repeated ToolName tool_names = 2;
}

message ToolCall {
  string session_id = 1;

  // Correlates callbacks with Execute before ExecutionStarted is received.
  string execution_id = 2;
  string cell_id = 3;
  string invocation_id = 4;
  string runtime_tool_call_id = 5;
  ToolName tool_name = 6;
  ToolKind tool_kind = 7;
  optional bytes input_json = 8;

  // Starts at one and increases independently for each execution.
  uint64 sequence = 9;

  // The host tool invocation span's W3C parent context for this streamed callback.
  // gRPC metadata is fixed when the subscription stream opens, so each call
  // carries its own context in the message.
  optional string traceparent = 10;
}

message CompleteToolCallRequest {
  string session_id = 1;
  string invocation_id = 2;

  oneof outcome {
    ToolCallSucceeded succeeded = 3;
    ToolCallFailed failed = 4;
  }
}

message ToolCallSucceeded {
  bytes output_json = 1;
}

message ToolCallFailed {
  string message = 1;
}

message CompleteToolCallResponse {}

message ToolCallCancelled {
  string invocation_id = 1;

  // Cancellation can arrive before the corresponding ToolCall because session
  // control events and tool subscriptions use independent HTTP/2 streams.
}

message Notification {
  string notification_id = 1;
  string execution_id = 2;
  string cell_id = 3;
  string call_id = 4;
  string text = 5;
}

message NotificationCancelled {
  string notification_id = 1;
}

message AcknowledgeNotificationRequest {
  string session_id = 1;
  string notification_id = 2;
}

message AcknowledgeNotificationResponse {}

message CellClosed {
  string execution_id = 1;
  string cell_id = 2;

  // Last tool-call sequence issued before closure. Clients may retire the cell
  // immediately and reject tool calls delivered after its closure.
  uint64 final_tool_call_sequence = 3;
}

message ExecuteRequest {
  string session_id = 1;

  // Chosen by the client so callbacks can be correlated before cell admission.
  string execution_id = 2;
  string tool_call_id = 3;
  string source = 4;
  repeated ToolDefinition enabled_tools = 5;
  optional uint64 yield_time_ms = 6;
  optional uint64 max_output_tokens = 7;
}

message ExecuteEvent {
  oneof event {
    ExecutionStarted started = 1;
    ExecutionOutcome outcome = 2;
  }
}

message ExecutionStarted {
  string execution_id = 1;
  string cell_id = 2;
}

message WaitRequest {
  string session_id = 1;
  string cell_id = 2;
  string wait_id = 3;
  uint64 yield_time_ms = 4;
}

message WaitResponse {
  oneof state {
    ExecutionOutcome live_cell = 1;
    ExecutionOutcome missing_cell = 2;
  }
}

message CancelWaitRequest {
  string session_id = 1;
  string wait_id = 2;
}

message CancelWaitResponse {}

message TerminateRequest {
  string session_id = 1;
  string cell_id = 2;
}

message ExecutionOutcome {
  string cell_id = 1;
  repeated ContentItem content_items = 2;

  // Elapsed monotonic time from receipt of this Execute, Wait, or Terminate
  // request until its outcome is ready, before serialization and delivery.
  // Includes nested tool waits, but not background time between requests.
  // Always supplied by the host; zero is a valid measurement.
  uint64 code_mode_host_duration_ns = 6;

  oneof outcome {
    ExecutionYielded yielded = 3;
    ExecutionTerminated terminated = 4;
    ExecutionCompleted completed = 5;
  }
}

message ExecutionYielded {}

message ExecutionTerminated {}

message ExecutionCompleted {
  optional string error_text = 1;
}

message ToolDefinition {
  string name = 1;
  ToolName tool_name = 2;
  string description = 3;
  ToolKind kind = 4;
  optional bytes input_schema_json = 5;
  optional bytes output_schema_json = 6;
}

message ToolName {
  string name = 1;
  optional string namespace = 2;
}

enum ToolKind {
  TOOL_KIND_UNSPECIFIED = 0;
  TOOL_KIND_FUNCTION = 1;
  TOOL_KIND_FREEFORM = 2;
}

message ContentItem {
  oneof item {
    TextContent text = 1;
    ImageContent image = 2;
    AudioContent audio = 3;
  }
}

message TextContent {
  string text = 1;
}

message ImageContent {
  string image_url = 1;
  optional ImageDetail detail = 2;
}

message AudioContent {
  string audio_url = 1;
}

enum ImageDetail {
  IMAGE_DETAIL_UNSPECIFIED = 0;
  IMAGE_DETAIL_AUTO = 1;
  IMAGE_DETAIL_LOW = 2;
  IMAGE_DETAIL_HIGH = 3;
  IMAGE_DETAIL_ORIGINAL = 4;
}