# 🤖 Build resilient AI workflows with automatic GPT and Gemini failover chain

This workflow demonstrates how to create a resilient AI Agent that automatically falls back to a different language model if the primary one fails. This is useful for handling API errors, rate limits, or model outages without interrupting your process.

1. **State Initialization:** The `Agent Variables` node initializes a `fail_count` to 0. This counter tracks how many models have been attempted.
2. **Dynamic Model Selection:** The `Fallback Models` (a LangChain Code node) acts as a router. It receives a list of all connected AI models and, based on the current `fail_count`, selects which one to use for this attempt (0 for the first model, 1 for the second, etc.).
3. **Agent Execution:** The `AI Agent` node attempts to run your prompt using the model selected by the router.
4. **The Fallback Loop:**
   - **On Success:** The workflow completes successfully.
   - **On Error:** If the `AI Agent` node fails, its "On Error" output is triggered. This path loops back to the `Agent Variables` node, which increments the `fail_count` by 1. The process then repeats, causing the `Fallback Models` router to select the _next_ model in the list.
5. **Final Failure:** If all connected models are tried and fail, the workflow will stop with an error.

### Set up steps

**Setup time: ~3-5 minutes**

1. **Configure Credentials:** Ensure you have the necessary credentials (e.g., for OpenAI, Google AI) configured in your n8n instance.
2. **Define Your Model Chain:**
   - Add the AI model nodes you want to use to the canvas (e.g., OpenAI, Google Gemini, Anthropic).
   - Connect them to the **`Fallback Models`** node.
   - **Important:** The order in which you connect the models determines the fallback order. The model nodes first created/connected will be tried first.
3. **Set Your Prompt:** Open the **`AI Agent`** node and enter the prompt you want to execute.
4. **Test:** Run the workflow. To test the fallback logic, you can temporarily disable the `First Model` node or configure it with invalid credentials to force an error.