fix(agent): implement AgentProtocol disposal to prevent memory leaks

packages/core/src/agent/agent-session.ts

@@ -34,6 +34,10 @@ export class AgentSession implements AgentProtocol {
     return this._protocol.abort();
   }
 
+  dispose(): void {
+    this._protocol.dispose?.();
+  }
+
   get events(): readonly AgentEvent[] {
     return this._protocol.events;
   }

packages/core/src/agent/legacy-agent-session.ts

@@ -71,6 +71,7 @@ export class LegacyAgentProtocol implements AgentProtocol {
   private _agentEndEmitted = false;
   private _activeStreamId?: string;
   private _abortController = new AbortController();
+  private _disposalController = new AbortController();
   private _nextStreamIdOverride?: string;
   private _lastToolStatuses = new Map<string, ToolEventStatus>();
 
@@ -106,10 +107,16 @@ export class LegacyAgentProtocol implements AgentProtocol {
       this._config.messageBus.subscribe(
         MessageBusType.TOOL_CALLS_UPDATE,
         this._handleToolCallsUpdate.bind(this),
+        { signal: this._disposalController.signal },
       );
     }
   }
 
+  dispose(): void {
+    this._disposalController.abort();
+    void this.abort();
+  }
+
   get events(): readonly AgentEvent[] {
     return this._events;
   }

packages/core/src/agent/types.ts

@@ -37,6 +37,11 @@ export interface AgentProtocol extends Trajectory {
    */
   abort(): Promise<void>;
 
+  /**
+   * Disposes of the protocol, cleaning up any long-lived resources.
+   */
+  dispose?(): void;
+
   /**
    * AgentProtocol implements the Trajectory interface and can retrieve existing events.
    */