Agent Fallbacks

When to use

Use an agent fallback as a failsafe when a one step action unexpectedly becomes a multi-step flow.

How it works

act() is attempted for the direct action
If it fails, agent() figures out the new path
Agent completes all needed steps (open menu → click button)

Example scenario

Before: Sign in button was in the header
After: Sign in now requires: Click account menu → Click “Sign in” option A single act("click sign in") can’t handle this change. The agent fallback can discover and execute both steps.

import { Stagehand } from "@browserbasehq/stagehand";

try {
  await stagehand.act("click the 'Sign In' button");
} catch (err) {
  console.log("Agent fallback triggered");

  const agent = stagehand.agent({
    model: "anthropic/claude-sonnet-4-6",
    systemPrompt: "You are a helpful assistant that can use a web browser.",
  });

  const result = await agent.execute({
    instruction: "Find and click Sign In button",
    maxSteps: 10,
  });

  console.log(result.success ? "Agent fallback success" : "Agent fallback failed");

  if (!result.success) throw err;
}

See all available agent models on the models page.

First Steps

The Basics

Configuration

Best Practices

Integrations

Reference

Migration Guides

When to use

How it works

Example scenario

​When to use

​How it works

​Example scenario

When to use

How it works

Example scenario