18. The Agent Class

export class Agent {
  private _state: MutableAgentState;
  private readonly listeners = new Set<(event: AgentEvent) => Promise<void> | void>();
  private readonly steeringQueue: PendingMessageQueue;
  private readonly followUpQueue: PendingMessageQueue;
  private activeRun?: ActiveRun;

  constructor(options: AgentOptions = {}) {
    this._state = createMutableAgentState(options.initialState);
    this.convertToLlm = options.convertToLlm ?? defaultConvertToLlm;
    this.streamFn = options.streamFn ?? streamSimple;
    // ...
  }

  /** Start a new prompt */
  async prompt(input: string): Promise<void> {
    if (this.activeRun) throw new Error("Already processing");
    const messages = this.normalizePromptInput(input);
    await this.runPromptMessages(messages);
  }

  /** Abort the current run */
  abort(): void {
    this.activeRun?.abortController.abort();
  }

  /** Subscribe to agent events */
  subscribe(listener: (event: AgentEvent) => void): () => void {
    this.listeners.add(listener);
    return () => this.listeners.delete(listener);
  }
}