refactor: bind the tool declaration once in get_tools_info

Co-authored-by: George Weale <gweale@google.com>
PiperOrigin-RevId: 957382413

src/google/adk/utils/agent_info.py

@@ -46,10 +46,11 @@ async def get_tools_info(tools: list[ToolUnion]) -> list[Any]:
       final_tools.extend(tools_res)
     else:
       final_tools.append(FunctionTool(tool))
+  declarations = (tool._get_declaration() for tool in final_tools)
   return [
-      types.Tool(function_declarations=[tool._get_declaration()])
-      for tool in final_tools
-      if tool._get_declaration()
+      types.Tool(function_declarations=[declaration])
+      for declaration in declarations
+      if declaration
   ]
 
 

tests/unittests/utils/test_agent_info.py

@@ -0,0 +1,98 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+from typing import Optional
+
+from google.adk.tools.base_tool import BaseTool
+from google.adk.tools.base_toolset import BaseToolset
+from google.adk.utils.agent_info import get_tools_info
+from google.genai import types
+import pytest
+
+
+class _CountingTool(BaseTool):
+  """A tool that records how many times its declaration was requested."""
+
+  def __init__(self, name: str, *, declared: bool = True):
+    super().__init__(name=name, description=f'{name} description')
+    self.declaration_calls = 0
+    self._declared = declared
+
+  def _get_declaration(self) -> Optional[types.FunctionDeclaration]:
+    self.declaration_calls += 1
+    if not self._declared:
+      return None
+    return types.FunctionDeclaration(
+        name=self.name, description=self.description
+    )
+
+
+class _CountingToolset(BaseToolset):
+
+  def __init__(self, tools: list[BaseTool]):
+    super().__init__()
+    self._tools = tools
+
+  async def get_tools(self, readonly_context=None) -> list[BaseTool]:
+    return self._tools
+
+  async def close(self) -> None:
+    pass
+
+
+@pytest.mark.asyncio
+async def test_get_tools_info_calls_get_declaration_once_per_tool():
+  declared = _CountingTool('declared_tool')
+  undeclared = _CountingTool('undeclared_tool', declared=False)
+  in_toolset = _CountingTool('toolset_tool')
+
+  tools_info = await get_tools_info(
+      [declared, undeclared, _CountingToolset([in_toolset])]
+  )
+
+  assert declared.declaration_calls == 1
+  assert undeclared.declaration_calls == 1
+  assert in_toolset.declaration_calls == 1
+  assert tools_info == [
+      types.Tool(
+          function_declarations=[
+              types.FunctionDeclaration(
+                  name='declared_tool', description='declared_tool description'
+              )
+          ]
+      ),
+      types.Tool(
+          function_declarations=[
+              types.FunctionDeclaration(
+                  name='toolset_tool', description='toolset_tool description'
+              )
+          ]
+      ),
+  ]
+
+
+@pytest.mark.asyncio
+async def test_get_tools_info_wraps_plain_callable():
+  def echo(text: str) -> str:
+    """Echoes the text."""
+    return text
+
+  tools_info = await get_tools_info([echo])
+
+  assert len(tools_info) == 1
+  declaration = tools_info[0].function_declarations[0]
+  assert declaration.name == 'echo'
+  assert declaration.description == 'Echoes the text.'