Method switchModel

extensions/cli/src/services/ModelService.ts:181–258

* Switch to a different chat model by index

(modelIndex: number)

   * Switch to a different chat model by index
   */
  async switchModel(modelIndex: number): Promise<ModelServiceState> {
    // Get assistant and authConfig from state, but fall back to instance properties
    // This is needed during initialization when state isn't set yet
    const stateValues = this.getState();
    const assistant = stateValues.assistant || this.assistant;
    const authConfig = stateValues.authConfig || this.authConfig;

    // Debug logging to understand the state
    logger.debug("switchModel: Checking state", {
      hasStateAssistant: !!stateValues.assistant,
      hasStateAuthConfig: !!stateValues.authConfig,
      hasInstanceAssistant: !!this.assistant,
      hasInstanceAuthConfig: !!this.authConfig,
      isInitialized: this.isReady(),
      isReady: this.isReady(),
      modelIndex,
    });

    if (!assistant) {
      logger.error("switchModel: Missing assistant data", {
        assistant: !!assistant,
        authConfig: !!authConfig,
        stateKeys: Object.keys(stateValues),
        currentState: {
          hasLlmApi: !!stateValues.llmApi,
          hasModel: !!stateValues.model,
          hasAssistant: !!stateValues.assistant,
          hasAuthConfig: !!stateValues.authConfig,
        },
      });
      throw new Error("ModelService not initialized - assistant data missing");
    }

    // Get available models from assistant in state
    const availableModels = (assistant.models?.filter(
      (model) =>
        model && (model.roles?.includes("chat") || model.roles === undefined),
    ) || []) as ModelConfig[];

    if (modelIndex < 0 || modelIndex >= availableModels.length) {
      throw new Error(
        `Invalid model index: ${modelIndex}. Available models: 0-${availableModels.length - 1}`,
      );
    }

    const selectedModel = availableModels[modelIndex];
    logger.debug("Switching to model", {
      modelIndex,
      provider: selectedModel.provider,
      name: (selectedModel as any).name || "unnamed",
    });

    try {
      const llmApi = createLlmApi(selectedModel, authConfig);

      if (!llmApi) {
        throw new Error("Failed to initialize LLM with selected model");
      }