fix: fix parameter schema generation for gemini

this fixes https://github.com/google/adk-python/issues/1055
and https://github.com/google/adk-python/issues/881

PiperOrigin-RevId: 766288394

src/google/adk/tools/openapi_tool/openapi_spec_parser/__init__.py

@@ -20,7 +20,6 @@ from .operation_parser import OperationParser
 from .rest_api_tool import AuthPreparationState
 from .rest_api_tool import RestApiTool
 from .rest_api_tool import snake_to_lower_camel
-from .rest_api_tool import to_gemini_schema
 from .tool_auth_handler import ToolAuthHandler
 
 __all__ = [
@@ -30,7 +29,6 @@ __all__ = [
     'OpenAPIToolset',
     'OperationParser',
     'RestApiTool',
-    'to_gemini_schema',
     'snake_to_lower_camel',
     'AuthPreparationState',
     'ToolAuthHandler',

src/google/adk/tools/openapi_tool/openapi_spec_parser/openapi_spec_parser.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import annotations
+
 import copy
 from typing import Any
 from typing import Dict
@@ -23,8 +25,8 @@ from pydantic import BaseModel
 
 from ....auth.auth_credential import AuthCredential
 from ....auth.auth_schemes import AuthScheme
+from ..._gemini_schema_util import _to_snake_case
 from ..common.common import ApiParameter
-from ..common.common import to_snake_case
 from .operation_parser import OperationParser
 
 
@@ -112,7 +114,7 @@ class OpenApiSpecParser:
         # If operation ID is missing, assign an operation id based on path
         # and method
         if "operationId" not in operation_dict:
-          temp_id = to_snake_case(f"{path}_{method}")
+          temp_id = _to_snake_case(f"{path}_{method}")
           operation_dict["operationId"] = temp_id
 
         url = OperationEndpoint(base_url=base_url, path=path, method=method)

src/google/adk/tools/openapi_tool/openapi_spec_parser/operation_parser.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import annotations
+
 import inspect
 from textwrap import dedent
 from typing import Any
@@ -25,9 +27,9 @@ from fastapi.openapi.models import Operation
 from fastapi.openapi.models import Parameter
 from fastapi.openapi.models import Schema
 
+from ..._gemini_schema_util import _to_snake_case
 from ..common.common import ApiParameter
 from ..common.common import PydocHelper
-from ..common.common import to_snake_case
 
 
 class OperationParser:
@@ -189,7 +191,7 @@ class OperationParser:
     operation_id = self._operation.operationId
     if not operation_id:
       raise ValueError('Operation ID is missing')
-    return to_snake_case(operation_id)[:60]
+    return _to_snake_case(operation_id)[:60]
 
   def get_return_type_hint(self) -> str:
     """Returns the return type hint string (like 'str', 'int', etc.)."""

src/google/adk/tools/openapi_tool/openapi_spec_parser/rest_api_tool.py

@@ -12,45 +12,36 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import annotations
+
 from typing import Any
 from typing import Dict
 from typing import List
 from typing import Literal
 from typing import Optional
-from typing import Sequence
 from typing import Tuple
 from typing import Union
 
 from fastapi.openapi.models import Operation
 from google.genai.types import FunctionDeclaration
-from google.genai.types import Schema
 import requests
 from typing_extensions import override
 
 from ....auth.auth_credential import AuthCredential
 from ....auth.auth_schemes import AuthScheme
-from ....tools.base_tool import BaseTool
+from ..._gemini_schema_util import _to_gemini_schema
+from ..._gemini_schema_util import _to_snake_case
+from ...base_tool import BaseTool
 from ...tool_context import ToolContext
 from ..auth.auth_helpers import credential_to_param
 from ..auth.auth_helpers import dict_to_auth_scheme
 from ..auth.credential_exchangers.auto_auth_credential_exchanger import AutoAuthCredentialExchanger
 from ..common.common import ApiParameter
-from ..common.common import to_snake_case
 from .openapi_spec_parser import OperationEndpoint
 from .openapi_spec_parser import ParsedOperation
 from .operation_parser import OperationParser
 from .tool_auth_handler import ToolAuthHandler
 
-# Not supported by the Gemini API
-_OPENAPI_SCHEMA_IGNORE_FIELDS = (
-    "title",
-    "default",
-    "format",
-    "additional_properties",
-    "ref",
-    "def",
-)
-
 
 def snake_to_lower_camel(snake_case_string: str):
   """Converts a snake_case string to a lower_camel_case string.
@@ -70,117 +61,6 @@ def snake_to_lower_camel(snake_case_string: str):
   ])
 
 
-# TODO: Switch to Gemini `from_json_schema` util when it is released
-# in Gemini SDK.
-def normalize_json_schema_type(
-    json_schema_type: Optional[Union[str, Sequence[str]]],
-) -> tuple[Optional[str], bool]:
-  """Converts a JSON Schema Type into Gemini Schema type.
-
-  Adopted and modified from Gemini SDK. This gets the first available schema
-  type from JSON Schema, and use it to mark Gemini schema type. If JSON Schema
-  contains a list of types, the first non null type is used.
-
-  Remove this after switching to Gemini `from_json_schema`.
-  """
-  if json_schema_type is None:
-    return None, False
-  if isinstance(json_schema_type, str):
-    if json_schema_type == "null":
-      return None, True
-    return json_schema_type, False
-
-  non_null_types = []
-  nullable = False
-  # If json schema type is an array, pick the first non null type.
-  for type_value in json_schema_type:
-    if type_value == "null":
-      nullable = True
-    else:
-      non_null_types.append(type_value)
-  non_null_type = non_null_types[0] if non_null_types else None
-  return non_null_type, nullable
-
-
-# TODO: Switch to Gemini `from_json_schema` util when it is released
-# in Gemini SDK.
-def to_gemini_schema(openapi_schema: Optional[Dict[str, Any]] = None) -> Schema:
-  """Converts an OpenAPI schema dictionary to a Gemini Schema object.
-
-  Args:
-      openapi_schema: The OpenAPI schema dictionary.
-
-  Returns:
-      A Pydantic Schema object.  Returns None if input is None.
-      Raises TypeError if input is not a dict.
-  """
-  if openapi_schema is None:
-    return None
-
-  if not isinstance(openapi_schema, dict):
-    raise TypeError("openapi_schema must be a dictionary")
-
-  pydantic_schema_data = {}
-
-  # Adding this to force adding a type to an empty dict
-  # This avoid "... one_of or any_of must specify a type" error
-  if not openapi_schema.get("type"):
-    openapi_schema["type"] = "object"
-
-  for key, value in openapi_schema.items():
-    snake_case_key = to_snake_case(key)
-    # Check if the snake_case_key exists in the Schema model's fields.
-    if snake_case_key in Schema.model_fields:
-      if snake_case_key in _OPENAPI_SCHEMA_IGNORE_FIELDS:
-        # Ignore these fields as Gemini backend doesn't recognize them, and will
-        # throw exception if they appear in the schema.
-        # Format: properties[expiration].format: only 'enum' and 'date-time' are
-        # supported for STRING type
-        continue
-      elif snake_case_key == "type":
-        schema_type, nullable = normalize_json_schema_type(
-            openapi_schema.get("type", None)
-        )
-        # Adding this to force adding a type to an empty dict
-        # This avoid "... one_of or any_of must specify a type" error
-        pydantic_schema_data["type"] = schema_type if schema_type else "object"
-        pydantic_schema_data["type"] = pydantic_schema_data["type"].upper()
-        if nullable:
-          pydantic_schema_data["nullable"] = True
-      elif snake_case_key == "properties" and isinstance(value, dict):
-        pydantic_schema_data[snake_case_key] = {
-            k: to_gemini_schema(v) for k, v in value.items()
-        }
-      elif snake_case_key == "items" and isinstance(value, dict):
-        pydantic_schema_data[snake_case_key] = to_gemini_schema(value)
-      elif snake_case_key == "any_of" and isinstance(value, list):
-        pydantic_schema_data[snake_case_key] = [
-            to_gemini_schema(item) for item in value
-        ]
-      # Important:  Handle cases where the OpenAPI schema might contain lists
-      # or other structures that need to be recursively processed.
-      elif isinstance(value, list) and snake_case_key not in (
-          "enum",
-          "required",
-          "property_ordering",
-      ):
-        new_list = []
-        for item in value:
-          if isinstance(item, dict):
-            new_list.append(to_gemini_schema(item))
-          else:
-            new_list.append(item)
-        pydantic_schema_data[snake_case_key] = new_list
-      elif isinstance(value, dict) and snake_case_key not in ("properties"):
-        # Handle dictionary which is neither properties or items
-        pydantic_schema_data[snake_case_key] = to_gemini_schema(value)
-      else:
-        # Simple value assignment (int, str, bool, etc.)
-        pydantic_schema_data[snake_case_key] = value
-
-  return Schema(**pydantic_schema_data)
-
-
 AuthPreparationState = Literal["pending", "done"]
 
 
@@ -273,7 +153,7 @@ class RestApiTool(BaseTool):
         parsed.operation, parsed.parameters, parsed.return_value
     )
 
-    tool_name = to_snake_case(operation_parser.get_function_name())
+    tool_name = _to_snake_case(operation_parser.get_function_name())
     generated = cls(
         name=tool_name,
         description=parsed.operation.description
@@ -306,7 +186,7 @@ class RestApiTool(BaseTool):
   def _get_declaration(self) -> FunctionDeclaration:
     """Returns the function declaration in the Gemini Schema format."""
     schema_dict = self._operation_parser.get_json_schema()
-    parameters = to_gemini_schema(schema_dict)
+    parameters = _to_gemini_schema(schema_dict)
     function_decl = FunctionDeclaration(
         name=self.name, description=self.description, parameters=parameters
     )