gridworld-env / OpenEnv /examples /browsergym_example.py
Abhilasha Kakoty
Initial deploy
7078f4d
"""BrowserGym MiniWoB example with Qwen deciding the next action.
This is an inference example for the BrowserGym environment. It uses the OpenAI
client and a vision language model to decide the next action. We use Hugging Face
Inference Providers API to access the model, but you can use any other provider that
is compatible with the OpenAI API.
Prerequisites:
- (Optional) Export the MiniWoB URL if you are hosting the tasks yourself
(must include the `/miniwob/` suffix); the BrowserGym Docker image now
serves the MiniWoB bundle internally on port 8888.
- Export your Hugging Face token for the router:
`export HF_TOKEN=your_token_here`
Usage:
python examples/browsergym_example.py
"""
import os
import re
import base64
import textwrap
from io import BytesIO
from typing import List, Optional, Dict
from openai import OpenAI
import numpy as np
from PIL import Image
from browsergym_env import BrowserGymAction, BrowserGymEnv
API_BASE_URL = "https://router.huggingface.co/v1"
API_KEY = os.getenv("HF_TOKEN") or os.getenv("API_KEY")
MODEL_NAME = "Qwen/Qwen3-VL-30B-A3B-Instruct:novita"
MAX_STEPS = 8
MAX_DOM_CHARS = 3500
TEMPERATURE = 0.2
MAX_TOKENS = 200
FALLBACK_ACTION = "noop()"
DEBUG = True
ACTION_PREFIX_RE = re.compile(
r"^(action|next action)\s*[:\-]\s*",
re.IGNORECASE,
)
ACTION_PATTERN = re.compile(r"[A-Za-z_]+\s*\(.*\)", re.DOTALL)
SYSTEM_PROMPT = textwrap.dedent(
"""
You control a web browser through BrowserGym.
Reply with exactly one action string.
The action must be a valid BrowserGym command such as:
- noop()
- click('<BID>')
- type('selector', 'text to enter')
- fill('selector', 'text to enter')
- send_keys('Enter')
- scroll('down')
Use single quotes around string arguments.
When clicking, use the BrowserGym element IDs (BIDs) listed in the user message.
If you are unsure, respond with noop().
Do not include explanations or additional text.
"""
).strip()
def build_history_lines(history: List[str]) -> str:
if not history:
return "None"
return "\n".join(history[-4:])
def extract_screenshot_uri(observation) -> Optional[str]:
if observation.screenshot is None:
return None
screen_array = np.array(observation.screenshot, dtype=np.uint8)
image = Image.fromarray(screen_array)
buffer = BytesIO()
image.save(buffer, format="PNG")
buffer.seek(0)
data_uri = base64.b64encode(buffer.read()).decode("utf-8")
return f"data:image/png;base64,{data_uri}"
def extract_clickable_elements(observation) -> List[Dict[str, str]]:
"""Collect BrowserGym element IDs that can be clicked."""
metadata = getattr(observation, "metadata", {}) or {}
obs_dict = metadata.get("browsergym_obs", {}) or {}
extra_props = obs_dict.get("extra_element_properties", {}) or {}
clickables: List[Dict[str, str]] = []
for bid, props in extra_props.items():
if not props.get("clickable"):
continue
bbox = props.get("bbox") or []
bbox_str = ", ".join(bbox) if bbox else "?"
clickables.append(
{
"bid": str(bid),
"bbox": bbox_str,
}
)
# Keep a stable ordering for readability
clickables.sort(key=lambda item: item["bid"])
return clickables
def build_user_prompt(step: int, observation, history: List[str]) -> str:
goal = observation.goal or "(not provided)"
url = observation.url or "(unknown)"
error_note = "Yes" if observation.last_action_error else "No"
clickables = extract_clickable_elements(observation)
if clickables:
actions_hint = "\n".join(
f" - {item['bid']} (bbox: {item['bbox']})" for item in clickables
)
else:
actions_hint = " (none detected)"
prompt = textwrap.dedent(
f"""
Step: {step}
Goal: {goal}
Current URL: {url}
Previous steps:
{build_history_lines(history)}
Last action error: {error_note}
Available clickable element IDs: {actions_hint}
Reply with exactly one BrowserGym action string.
"""
).strip()
return prompt
def parse_model_action(response_text: str) -> str:
if not response_text:
return FALLBACK_ACTION
# Prefer the first line that looks like an action string
lines = response_text.splitlines()
for raw_line in lines:
line = raw_line.strip()
if not line:
continue
line = ACTION_PREFIX_RE.sub("", line)
match = ACTION_PATTERN.search(line)
if match:
action = match.group(0).strip()
# Collapse internal whitespace
action = re.sub(r"\s+", " ", action)
# If the model tried to click by natural-language description while we
# only exposed numeric BrowserGym IDs, fallback to the single detected ID.
return action
# Fall back to searching the whole response
match = ACTION_PATTERN.search(response_text)
if match:
action = match.group(0).strip()
action = re.sub(r"\s+", " ", action)
return action
return FALLBACK_ACTION
def main() -> None:
client = OpenAI(base_url=API_BASE_URL, api_key=API_KEY)
env = BrowserGymEnv.from_docker_image(
image="browsergym-env:latest",
env_vars={
"BROWSERGYM_BENCHMARK": "miniwob",
"BROWSERGYM_TASK_NAME": "click-test",
},
)
history: List[str] = []
try:
result = env.reset()
observation = result.observation
print(f"Episode goal: {observation.goal}")
for step in range(1, MAX_STEPS + 1):
if result.done:
print("Environment signalled done. Stopping early.")
break
user_prompt = build_user_prompt(step, observation, history)
user_content = [{"type": "text", "text": user_prompt}]
screenshot_uri = extract_screenshot_uri(observation)
if screenshot_uri:
user_content.append(
{
"type": "image_url",
"image_url": {"url": screenshot_uri},
}
)
messages = [
{
"role": "system",
"content": [{"type": "text", "text": SYSTEM_PROMPT}],
},
{
"role": "user",
"content": user_content,
},
]
try:
completion = client.chat.completions.create(
model=MODEL_NAME,
messages=messages,
temperature=TEMPERATURE,
max_tokens=MAX_TOKENS,
stream=False,
)
response_text = completion.choices[0].message.content or ""
# pylint: disable=broad-except
except Exception as exc: # noqa: BLE001
failure_msg = f"Model request failed ({exc}). Using fallback action."
print(failure_msg)
response_text = FALLBACK_ACTION
action_str = parse_model_action(response_text)
print(f"Step {step}: model suggested -> {action_str}")
result = env.step(BrowserGymAction(action_str=action_str))
observation = result.observation
reward = result.reward or 0.0
error_flag = " ERROR" if observation.last_action_error else ""
history_line = (
f"Step {step}: {action_str} -> reward {reward:+.2f}{error_flag}"
)
history.append(history_line)
print(
" Reward: "
f"{reward:+.2f} | Done: {result.done} | Last action error: "
f"{observation.last_action_error}"
)
if result.done:
print("Episode complete.")
break
else:
print(f"Reached max steps ({MAX_STEPS}).")
finally:
env.close()
if __name__ == "__main__":
main()