Add automatic CUA_API_KEY environment variable support for Computer and CloudProvider

Previously, users had to explicitly read the CUA_API_KEY environment variable
and pass it to the Computer/CloudProvider constructor. This change makes the
API key parameter optional and automatically reads from the CUA_API_KEY
environment variable if not provided.

Changes:
- CloudProvider.__init__: Made api_key parameter optional, reads from CUA_API_KEY env var
- Computer.__init__: Added fallback to CUA_API_KEY env var for api_key parameter
- Updated documentation examples to show simplified usage without explicit api_key
- Updated cloud_api_examples.py to demonstrate the new simpler pattern

This provides a cleaner API while maintaining backward compatibility with
explicit api_key parameter passing.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

docs/content/docs/computer-sdk/cloud-vm-management.mdx

@@ -17,16 +17,16 @@ All examples require a CUA API key. You can obtain one from the [Dashboard](http
   <Tab value="Python">
 
 ```python
-import os
 import asyncio
 from computer.providers.cloud.provider import CloudProvider
 
 async def main():
-    api_key = os.getenv("CUA_API_KEY") or "your-api-key"
+    # CloudProvider automatically reads CUA_API_KEY from environment
+    # You can also pass api_key explicitly: CloudProvider(api_key="your-api-key")
     # Optional: point to a different API base
     # os.environ["CUA_API_BASE"] = "https://api.cua.ai"
 
-    provider = CloudProvider(api_key=api_key, verbose=False)
+    provider = CloudProvider(verbose=False)
     async with provider:
         vms = await provider.list_vms()
         for vm in vms:
@@ -88,15 +88,14 @@ Provide the sandbox name you want to start.
   <Tab value="Python">
 
 ```python
-import os
 import asyncio
 from computer.providers.cloud.provider import CloudProvider
 
 async def main():
-    api_key = os.getenv("CUA_API_KEY") or "your-api-key"
+    # CloudProvider automatically reads CUA_API_KEY from environment
     name = "my-vm-name"  # e.g., "m-linux-96lcxd2c2k"
 
-    provider = CloudProvider(api_key=api_key)
+    provider = CloudProvider()
     async with provider:
         resp = await provider.run_vm(name)
         print(resp)  # { "name": name, "status": "starting" }
@@ -137,15 +136,14 @@ Stops the sandbox asynchronously.
   <Tab value="Python">
 
 ```python
-import os
 import asyncio
 from computer.providers.cloud.provider import CloudProvider
 
 async def main():
-    api_key = os.getenv("CUA_API_KEY") or "your-api-key"
+    # CloudProvider automatically reads CUA_API_KEY from environment
     name = "my-vm-name"
 
-    provider = CloudProvider(api_key=api_key)
+    provider = CloudProvider()
     async with provider:
         resp = await provider.stop_vm(name)
         print(resp)  # { "name": name, "status": "stopping" }
@@ -186,15 +184,14 @@ Restarts the sandbox asynchronously.
   <Tab value="Python">
 
 ```python
-import os
 import asyncio
 from computer.providers.cloud.provider import CloudProvider
 
 async def main():
-    api_key = os.getenv("CUA_API_KEY") or "your-api-key"
+    # CloudProvider automatically reads CUA_API_KEY from environment
     name = "my-vm-name"
 
-    provider = CloudProvider(api_key=api_key)
+    provider = CloudProvider()
     async with provider:
         resp = await provider.restart_vm(name)
         print(resp)  # { "name": name, "status": "restarting" }
@@ -235,15 +232,14 @@ Query the computer-server running on the sandbox. Useful for checking details li
   <Tab value="Python">
 
 ```python
-import os
 import asyncio
 from computer.providers.cloud.provider import CloudProvider
 
 async def main():
-    api_key = os.getenv("CUA_API_KEY") or "your-api-key"
+    # CloudProvider automatically reads CUA_API_KEY from environment
     name = "my-vm-name"
 
-    provider = CloudProvider(api_key=api_key)
+    provider = CloudProvider()
     async with provider:
         info = await provider.get_vm(name)
         print(info)

examples/cloud_api_examples.py

@@ -9,14 +9,13 @@ from computer.providers.cloud.provider import CloudProvider
 
 
 async def main() -> None:
-    api_key = os.getenv("CUA_API_KEY")
-    if not api_key:
-        raise RuntimeError("CUA_API_KEY environment variable is not set")
+    # CloudProvider will automatically read CUA_API_KEY from environment if not provided
+    # You can still pass api_key explicitly if needed: CloudProvider(api_key="your_key")
     api_base = os.getenv("CUA_API_BASE")
     if api_base:
         print(f"Using API base: {api_base}")
 
-    provider = CloudProvider(api_key=api_key, verbose=True)
+    provider = CloudProvider(verbose=True)
     async with provider:
 
         # List all VMs

libs/python/computer/computer/computer.py

@@ -98,13 +98,17 @@ class Computer:
             host: Host to use for VM provider connections (e.g. "localhost", "host.docker.internal")
             storage: Optional path for persistent VM storage (Lumier provider)
             ephemeral: Whether to use ephemeral storage
-            api_key: Optional API key for cloud providers
+            api_key: Optional API key for cloud providers (defaults to CUA_API_KEY environment variable)
             experiments: Optional list of experimental features to enable (e.g. ["app-use"])
         """
 
         self.logger = Logger("computer", verbosity)
         self.logger.info("Initializing Computer...")
 
+        # Fall back to environment variable for api_key if not provided
+        if api_key is None:
+            api_key = os.environ.get("CUA_API_KEY")
+
         if not image:
             if os_type == "macos":
                 image = "macos-sequoia-cua:latest"

libs/python/computer/computer/providers/cloud/provider.py

@@ -31,18 +31,21 @@ class CloudProvider(BaseVMProvider):
 
     def __init__(
         self,
-        api_key: str,
+        api_key: Optional[str] = None,
         verbose: bool = False,
         api_base: Optional[str] = None,
         **kwargs,
     ):
         """
         Args:
-            api_key: API key for authentication
+            api_key: API key for authentication (defaults to CUA_API_KEY environment variable)
             name: Name of the VM
             verbose: Enable verbose logging
         """
-        assert api_key, "api_key required for CloudProvider"
+        # Fall back to environment variable if api_key not provided
+        if api_key is None:
+            api_key = os.getenv("CUA_API_KEY")
+        assert api_key, "api_key required for CloudProvider (provide via parameter or CUA_API_KEY environment variable)"
         self.api_key = api_key
         self.verbose = verbose
         self.api_base = (api_base or DEFAULT_API_BASE).rstrip("/")