Adding initial support for LLM Customisation (#132)

* Adding support for LLM Customisation

* Added back model_api_key config

* Fixed README

* Update README.md

Co-authored-by: Miguel <36487034+miguelg719@users.noreply.github.com>

* Update stagehand/llm/client.py

---------

Co-authored-by: Miguel <36487034+miguelg719@users.noreply.github.com>

Author: sanveer-osahan

stagehand/config.py

@@ -20,6 +20,7 @@ class StagehandConfig(BaseModel):
         browserbase_session_id (Optional[str]): Session ID for resuming Browserbase sessions.
         model_name (Optional[str]): Name of the model to use.
         model_api_key (Optional[str]): Model API key.
+        model_client_options (Optional[dict[str, Any]]): Options for the model client.
         logger (Optional[Callable[[Any], None]]): Custom logging function.
         verbose (Optional[int]): Verbosity level for logs (1=minimal, 2=medium, 3=detailed).
         use_rich_logging (bool): Whether to use Rich for colorized logging.
@@ -50,6 +51,9 @@ class StagehandConfig(BaseModel):
     model_api_key: Optional[str] = Field(
         None, alias="modelApiKey", description="Model API key"
     )
+    model_client_options: Optional[dict[str, Any]] = Field(
+        None, alias="modelClientOptions", description="Configuration options for the language model client (i.e. apiKey, baseURL)",
+    )
     verbose: Optional[int] = Field(
         1,
         description="Verbosity level for logs: 0=minimal (ERROR), 1=medium (INFO), 2=detailed (DEBUG)",

stagehand/llm/client.py

@@ -54,7 +54,7 @@ def __init__(
                 setattr(litellm, key, value)
                 self.logger.debug(f"Set global litellm.{key}", category="llm")
             # Handle common aliases or expected config names if necessary
-            elif key == "api_base":  # Example: map api_base if needed
+            elif key == "api_base" or key == "baseURL":
                 litellm.api_base = value
                 self.logger.debug(
                     f"Set global litellm.api_base to {value}", category="llm"

stagehand/main.py

@@ -68,7 +68,11 @@ def __init__(
 
         # Handle non-config parameters
         self.api_url = self.config.api_url
-        self.model_api_key = self.config.model_api_key or os.getenv("MODEL_API_KEY")
+
+        # Handle model-related settings
+        self.model_client_options = self.config.model_client_options or {}
+        self.model_api_key = self.config.model_api_key or self.model_client_options.get("apiKey") or os.getenv("MODEL_API_KEY")
+
         self.model_name = self.config.model_name
 
         # Extract frequently used values from config for convenience
@@ -89,11 +93,6 @@ def __init__(
             self.config.local_browser_launch_options or {}
         )
 
-        # Handle model-related settings
-        self.model_client_options = {}
-        if self.model_api_key and "apiKey" not in self.model_client_options:
-            self.model_client_options["apiKey"] = self.model_api_key
-
         # Handle browserbase session create params
         self.browserbase_session_create_params = make_serializable(
             self.config.browserbase_session_create_params

tests/unit/llm/test_llm_integration.py

@@ -40,6 +40,7 @@ def test_llm_client_with_custom_options(self):
             api_key="test-key",
             default_model="gpt-4o-mini",
             stagehand_logger=StagehandLogger(),
+            api_base="https://test-api-base.com",
         )
 
         assert client.default_model == "gpt-4o-mini"

tests/unit/test_client_api.py

@@ -19,7 +19,7 @@ async def mock_client(self):
             browserbase_session_id="test-session-123",
             api_key="test-api-key",               
             project_id="test-project-id",
-            model_api_key="test-model-api-key",
+            model_client_options={"apiKey": "test-model-api-key"}
         )
         return client
 

tests/unit/test_client_initialization.py

@@ -23,7 +23,7 @@ def test_init_with_direct_params(self):
             browserbase_session_id="test-session",
             api_key="test-api-key",
             project_id="test-project-id",
-            model_api_key="test-model-api-key",
+            model_client_options={"apiKey": "test-model-api-key"},
             verbose=2,
         )
 
@@ -203,3 +203,32 @@ async def mock_create_session():
         # Call _create_session and expect error
         with pytest.raises(RuntimeError, match="Invalid response format"):
             await client._create_session()
+
+    @mock.patch.dict(os.environ, {"MODEL_API_KEY": "test-model-api-key"}, clear=True)
+    def test_init_with_model_api_key_in_env(self):
+        config = StagehandConfig(env="LOCAL")
+        client = Stagehand(config=config)
+        assert client.model_api_key == "test-model-api-key"
+
+    def test_init_with_custom_llm(self):
+        config = StagehandConfig(
+            env="LOCAL",
+            model_client_options={"apiKey": "custom-llm-key", "baseURL": "https://custom-llm.com"}
+        )
+        client = Stagehand(config=config)
+        assert client.model_api_key == "custom-llm-key"
+        assert client.model_client_options["apiKey"] == "custom-llm-key"
+        assert client.model_client_options["baseURL"] == "https://custom-llm.com"
+
+    def test_init_with_custom_llm_override(self):
+        config = StagehandConfig(
+            env="LOCAL",
+            model_client_options={"apiKey": "custom-llm-key", "baseURL": "https://custom-llm.com"}
+        )
+        client = Stagehand(
+            config=config,
+            model_client_options={"apiKey": "override-llm-key", "baseURL": "https://override-llm.com"}
+        )
+        assert client.model_api_key == "override-llm-key"
+        assert client.model_client_options["apiKey"] == "override-llm-key"
+        assert client.model_client_options["baseURL"] == "https://override-llm.com"