fix: incorrect logic in LlmRequest.append_tools and make BaseTool to call it

PiperOrigin-RevId: 792642882

Author: seanzhougoogle

src/google/adk/models/llm_request.py

@@ -24,6 +24,24 @@
 from ..tools.base_tool import BaseTool
 
 
+def _find_tool_with_function_declarations(
+    llm_request: LlmRequest,
+) -> Optional[types.Tool]:
+  """Find an existing Tool with function_declarations in the LlmRequest."""
+  # TODO: add individual tool with declaration and merge in google_llm.py
+  if not llm_request.config or not llm_request.config.tools:
+    return None
+
+  return next(
+      (
+          tool
+          for tool in llm_request.config.tools
+          if isinstance(tool, types.Tool) and tool.function_declarations
+      ),
+      None,
+  )
+
+
 class LlmRequest(BaseModel):
   """LLM request class that allows passing in tools, output schema and system
 
@@ -81,15 +99,26 @@ def append_tools(self, tools: list[BaseTool]) -> None:
       return
     declarations = []
     for tool in tools:
-      if isinstance(tool, BaseTool):
-        declaration = tool._get_declaration()
-      else:
-        declaration = tool.get_declaration()
+      declaration = tool._get_declaration()
       if declaration:
         declarations.append(declaration)
         self.tools_dict[tool.name] = tool
     if declarations:
-      self.config.tools.append(types.Tool(function_declarations=declarations))
+      if self.config.tools is None:
+        self.config.tools = []
+
+      # Find existing tool with function_declarations and append to it
+      if tool_with_function_declarations := _find_tool_with_function_declarations(
+          self
+      ):
+        if tool_with_function_declarations.function_declarations is None:
+          tool_with_function_declarations.function_declarations = []
+        tool_with_function_declarations.function_declarations.extend(
+            declarations
+        )
+      else:
+        # No existing tool with function_declarations, create new one
+        self.config.tools.append(types.Tool(function_declarations=declarations))
 
   def set_output_schema(self, base_model: type[BaseModel]) -> None:
     """Sets the output schema for the request.

src/google/adk/tools/base_tool.py

@@ -125,30 +125,8 @@ async def process_llm_request(
       tool_context: The context of the tool.
       llm_request: The outgoing LLM request, mutable this method.
     """
-    if (function_declaration := self._get_declaration()) is None:
-      return
-
-    llm_request.tools_dict[self.name] = self
-    if tool_with_function_declarations := _find_tool_with_function_declarations(
-        llm_request
-    ):
-      if tool_with_function_declarations.function_declarations is None:
-        tool_with_function_declarations.function_declarations = []
-      tool_with_function_declarations.function_declarations.append(
-          function_declaration
-      )
-    else:
-      llm_request.config = (
-          types.GenerateContentConfig()
-          if not llm_request.config
-          else llm_request.config
-      )
-      llm_request.config.tools = (
-          [] if not llm_request.config.tools else llm_request.config.tools
-      )
-      llm_request.config.tools.append(
-          types.Tool(function_declarations=[function_declaration])
-      )
+    # Use the consolidated logic in LlmRequest.append_tools
+    llm_request.append_tools([self])
 
   @property
   def _api_variant(self) -> GoogleLLMVariant:
@@ -232,20 +210,3 @@ def from_config(
         else:
           logger.warning("Unsupported parsing for argument: %s.", param_name)
     return cls(**kwargs)
-
-
-def _find_tool_with_function_declarations(
-    llm_request: LlmRequest,
-) -> Optional[types.Tool]:
-  # TODO: add individual tool with declaration and merge in google_llm.py
-  if not llm_request.config or not llm_request.config.tools:
-    return None
-
-  return next(
-      (
-          tool
-          for tool in llm_request.config.tools
-          if isinstance(tool, types.Tool) and tool.function_declarations
-      ),
-      None,
-  )