---
title: "Browser Use Agent"
description: "EMILY.RPA Browser Use Agent module: describe the goal in natural language and let a large language model operate the browser autonomously."
source: https://docs.emily.tips/en/ai-agent/browser-use-agent
---

# Browser Use Agent

Browser Use Agent uses natural language to describe the task goal and autonomously operates the browser through a large language model (LLM). Note that larger goals make the language model more prone to misjudgment and consume more tokens — it is recommended to break tasks into smaller sub-tasks to reduce failure rates. If you're unfamiliar with how to prompt the language model to achieve task goals, use "**Ask EMILY**" to let the AI generate model-friendly goal prompts.

![](https://docs.emily.tips/img/en/ai-agent-031.png)

## Parameters

**`API KEY`** - OpenAI or Google API key. Supports the **%FILENAME%** variable, or use the prepaid dedicated key **%credit-key%**.

* For OpenAI API Key, refer to [Apply for OpenAI Key](/faq/apply-openai-key)
* For Google API Key, refer to [Apply for Gemini Key](/faq/apply-gemini-key)

**`MODEL`** - Currently supported models:

| Platform  | Models                                                                        | Pricing                                                 | 
| --------- | ----------------------------------------------------------------------------- | ------------------------------------------------------- |
| OpenAI    | gtp-5, gpt-5-mini, gpt-4.1, gpt-4.1-mini, computer-use                       | [OpenAI Website](https://platform.openai.com/docs/models) |
| Google    | gemini-3-pro, gemini-3-flash, gemini-2.5-pro, gemini-2.5-flash, computer-use | [Gemini Website](https://ai.google.dev/gemini-api/docs/pricing) |
| Anthropic | claude-opus-4-6, claude-sonnet-4-6, claude-haiku-4-5, computer-use             | [Anthropic Website](https://docs.anthropic.com/en/docs/about-claude/models) |

**`MAX ACTION`** - Set the maximum number of actions the agent can perform, ranging from 1–100.

**`GUARDRAIL`** - Set the agent's operational scope restrictions:

* `SAME PAGE` - Current page only
* `SAME SITE` - Same domain only
* `NONE` - No restrictions

> Since model usage is billed by consumption, it is recommended to set **`MAX ACTION`** and **`GUARDRAIL`** parameters appropriately to avoid unexpected costs.

**`GOAL`** - Describe the task in natural language. Supports the **%FILENAME%** template.

**`ACTION`** - The next browser action determined and executed by the model. Each step automatically captures a screenshot, saved to the working folder for tracking and review.

## Example

Using a high-speed rail schedule query as an example, the query page defaults to departing from "Nangang" to "Zuoying", with date 2026/04/03 and time 18:00.

![](https://docs.emily.tips/img/en/ai-agent-032.png)

Use natural language to prompt the model: Query trains departing from "Taipei" to "Tainan" 9 AM on 2026/04/04. Then click "**TEST**" to execute.

![](https://docs.emily.tips/img/en/ai-agent-033.png)

Finally, check whether the content in the browser is correct.

![](https://docs.emily.tips/img/en/ai-agent-034.png)