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Overview

You can customize the system prompt in two ways:

  1. Extend the default system prompt with additional instructions
  2. Override the default system prompt entirely

Custom system prompts allow you to modify the agent’s behavior at a fundamental level. Use this feature carefully as it can significantly impact the agent’s performance and reliability.

To add additional instructions to the default system prompt:

from browser_use import Agent
from langchain_openai import ChatOpenAI

# Add your custom instructions
extend_system_message = """
REMEMBER the most important RULE:
ALWAYS open first a new tab and go first to url wikipedia.com no matter the task!!!
"""

# Create agent with extended system prompt
agent = Agent(
    task="Your task here",
    llm=ChatOpenAI(model='gpt-4'),
    extend_system_message=extend_system_message
)

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Override System Prompt

Not recommended! If you must override the default system prompt, make sure to test the agent yourself.

Anyway, to override the default system prompt:

# Define your complete custom prompt
override_system_message = """
You are an AI agent that helps users with web browsing tasks.

[Your complete custom instructions here...]
"""

# Create agent with custom system prompt
agent = Agent(
    task="Your task here",
    llm=ChatOpenAI(model='gpt-4'),
    override_system_message=override_system_message
)

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