> ## Documentation Index
> Fetch the complete documentation index at: https://laminar.sh/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Debugger with Browser Use
This guide is an end-to-end setup for running a `browser-use` agent with the Laminar Debugger so you can rerun from checkpoints.
## 1) Install prerequisites
Install `uv` if you do not already have it:
```bash theme={null}
pip install -U uv
```
Create a virtual environment and install dependencies:
```bash theme={null}
uv venv --python 3.11
source .venv/bin/activate
uv pip install lmnr browser-use python-dotenv
```
Install the Browser Use Chromium bundle:
```bash theme={null}
uvx browser-use install
```
If your Browser Use LLM provider needs extra packages or env vars, follow the provider setup in Browser Use docs.
## 2) Set environment variables
Create a `.env` file in your project root:
```bash theme={null}
LMNR_PROJECT_API_KEY=your_laminar_project_api_key
```
If you are using **ChatBrowserUse** (recommended), add:
```bash theme={null}
BROWSER_USE_API_KEY=your_browser_use_api_key
```
If you prefer **Claude**, add:
```bash theme={null}
ANTHROPIC_API_KEY=your_anthropic_api_key
CLAUDE_MODEL=your_claude_model_name
```
## 3) Create the entrypoint
```python theme={null}
import os
import asyncio
from dotenv import load_dotenv
from browser_use import Agent, ChatBrowserUse, ChatAnthropic
from lmnr import observe, Laminar
load_dotenv()
Laminar.initialize(project_api_key=os.getenv("LMNR_PROJECT_API_KEY"))
@observe(rollout_entrypoint=True)
async def main(prompt: str):
provider = os.getenv("LLM_PROVIDER", "chatbrowseruse")
if provider == "anthropic":
llm = ChatAnthropic(model=os.getenv("CLAUDE_MODEL"), temperature=0.0)
else:
llm = ChatBrowserUse()
agent = Agent(task=prompt, llm=llm)
history = await agent.run()
print(history.final_result())
if __name__ == "__main__":
asyncio.run(
main(
"go to ycombinator.com, summarize 3 startups from the summer 2025 batch."
# "go to laminar.sh, summarize the pricing page."
)
)
```
Notes:
* The `rollout_entrypoint=True` flag marks this function for debugger sessions.
* Keep the CLI running while you iterate; the debugger will rerun using the latest code on disk.
## 4) Start a debugger session
```bash theme={null}
npx lmnr-cli@latest dev path/to/entrypoint.py
```
If the file exposes multiple debugger entrypoints, pass `--function main`.
> \[Screenshot: terminal output with debugger session link]
## 5) Open the debugger in Laminar
Open **Debugger** in your project, select the session, provide input arguments as JSON, and click **Run**.
## 6) Make a change and rerun (Debugger workflow)
Use the Debugger to iterate without restarting your local process.
1. Open the trace in **Transcript** or **Tree** view.
2. Click the checkpoint icon on a span and choose **Run from here**.
3. Expand **System Prompts** and toggle **Override System Prompt** on for the Browser Automation Agent.
4. Edit the prompt in place, then click **Run** again to rerun with the updated instructions.
Notes:
* Keep the CLI running while you iterate; the debugger reruns using the latest code on disk.
* If you changed dependencies, restart the CLI.