Computer Use Agents

Patterns

Perception-Reasoning-Action Loop

The fundamental architecture of computer use agents: observe screen, reason about next action, execute action, repeat. This loop integrates vision models with action execution through an iterative pipeline.

Key components:

1. PERCEPTION: Screenshot captures current screen state
2. REASONING: Vision-language model analyzes and plans
3. ACTION: Execute mouse/keyboard operations
4. FEEDBACK: Observe result, continue or correct

Critical insight: Vision agents are completely still during "thinking" phase (1-5 seconds), creating a detectable pause pattern.

When to use: ['Building any computer use agent from scratch', 'Integrating vision models with desktop control', 'Understanding agent behavior patterns']

from anthropic import Anthropic
from PIL import Image
import base64
import pyautogui
import time

class ComputerUseAgent:
    """
    Perception-Reasoning-Action loop implementation.
    Based on Anthropic Computer Use patterns.
    """

    def __init__(self, client: Anthropic, model: str = "Codex-sonnet-4-20250514"):
        self.client = client
        self.model = model
        self.max_steps = 50  # Prevent runaway loops
        self.action_delay = 0.5  # Seconds between actions

    def capture_screenshot(self) -> str:
        """Capture screen and return base64 encoded image."""
        screenshot = pyautogui.screenshot()
        # Resize for token efficiency (1280x800 is good balance)
        screenshot = screenshot.resize((1280, 800), Image.LANCZOS)

        import io
        buffer = io.BytesIO()
        screenshot.save(buffer, format="PNG")
        return base64.b64encode(buffer.getvalue()).decode()

    def execute_action(self, action: dict) -> dict:
        """Execute mouse/keyboard action on the computer."""
        action_type = action.get("type")

        if action_type == "click":
            x, y = action["x"], action["y"]
            button = action.get("button", "left")
            pyautogui.click(x, y, button=button)
            return {"success": True, "action": f"clicked at ({x}, {y})"}

        elif action_type == "type":
            text = action["text"]
            pyautogui.typewrite(text, interval=0.02)
            return {"success": True, "action": f"typed {len(text)} chars"}

        elif action_type == "key":
            key = action["key"]
            pyautogui.press(key)
            return {"success": True, "action": f"pressed {key}"}

        elif action_type == "scroll":
            direction = action.get("direction", "down")
            amount = action.get("amount", 3)
            scroll = -amount if direction == "down" else amount
            pyautogui.scroll(scroll)
            return {"success": True, "action": f"scrolled {dir