chore: Remove redundant attribute descriptions from docstrings

The attributes are already defined as fields in the Pydantic models, making the docstring descriptions unnecessary.

PiperOrigin-RevId: 806091305

src/google/adk/events/event.py

@@ -11,6 +11,7 @@
 # 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 datetime import datetime
@@ -31,18 +32,6 @@ class Event(LlmResponse):
 
   It is used to store the content of the conversation, as well as the actions
   taken by the agents like function calls, etc.
-
-  Attributes:
-    invocation_id: Required. The invocation ID of the event. Should be non-empty
-      before appending to a session.
-    author: Required. "user" or the name of the agent, indicating who appended
-      the event to the session.
-    actions: The actions taken by the agent.
-    long_running_tool_ids: The ids of the long running function calls.
-    branch: The branch of the event.
-    id: The unique identifier of the event.
-    timestamp: The timestamp of the event.
-    get_function_calls: Returns the function calls in the event.
   """
 
   model_config = ConfigDict(

src/google/adk/models/base_llm.py

@@ -11,6 +11,7 @@
 # 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 abc import abstractmethod
@@ -29,11 +30,7 @@ if TYPE_CHECKING:
 
 
 class BaseLlm(BaseModel):
-  """The BaseLLM class.
+  """The BaseLLM class."""
-
-  Attributes:
-    model: The name of the LLM, e.g. gemini-2.5-flash or gemini-2.5-pro.
-  """
 
   model_config = ConfigDict(
       # This allows us to use arbitrary types in the model. E.g. PIL.Image.

src/google/adk/sessions/session.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import annotations
+
 from typing import Any
 
 from pydantic import alias_generators
@@ -23,17 +25,7 @@ from ..events.event import Event
 
 
 class Session(BaseModel):
-  """Represents a series of interactions between a user and agents.
+  """Represents a series of interactions between a user and agents."""
-
-  Attributes:
-    id: The unique identifier of the session.
-    app_name: The name of the app.
-    user_id: The id of the user.
-    state: The state of the session.
-    events: The events of the session, e.g. user input, model response, function
-      call/response, etc.
-    last_update_time: The last update time of the session.
-  """
 
   model_config = ConfigDict(
       extra='forbid',