Update to specification from 61d1e3a6f9a5d497b117b746e8547156e15f1e43

[a2a-bot]

Commit: a2aproject/A2A@61d1e3a

[gemini-code-assist]

Summary of Changes

Hello @a2a-bot, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request updates the A2A protocol specification, resulting in a comprehensive refresh of the generated Python protobuf and gRPC code. The changes focus on enhancing the API's structure and clarity by renaming methods and fields, introducing new functionalities like task listing, and refining data models with explicit required fields and improved documentation. This update ensures the codebase aligns with the latest protocol definition and improves overall API usability.

Highlights

• API Method Changes: Introduced a new ListTasks method for retrieving tasks with filtering and pagination. Existing methods TaskSubscription, CreateTaskPushNotificationConfig, and GetAgentCard have been renamed to SubscribeToTask, SetTaskPushNotificationConfig, and GetExtendedAgentCard respectively, improving clarity and consistency.
• Data Model Refinements: Several fields across various messages have been renamed for better semantics (e.g., push_notification to push_notification_config, mime_type to media_type, content to parts, transport to protocol_binding). Many fields are now explicitly marked as required, enforcing stricter data integrity.
• New Data Fields and Optionality: Added new fields such as reference_task_ids in Message, supported_interfaces in AgentCard, and state_transition_history in AgentCapabilities. Several fields have also been made optional, providing more flexibility in data representation.
• Internal Python Protobuf Optimization: The __slots__ attribute has been removed from most Python protobuf message classes in the generated a2a_pb2.py and a2a_pb2.pyi files, which can impact memory usage and attribute access performance.
• Specification Version Update: The underlying specification version referenced in src/a2a/types.py has been updated to v0.3.0, indicating a new release of the A2A protocol definition.

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[gemini-code-assist]

Code Review

This pull request updates the generated Python code to align with a new version of the A2A specification (commit 61d1e3a6f9a5...). The changes are mostly in auto-generated files (a2a_pb2.py, a2a_pb2.pyi, a2a_pb2_grpc.py, types.py) and correctly reflect many specification updates.

Critical Issues:
This PR is incomplete and will break the build. The gRPC service definition has changed, with several methods being renamed (e.g., TaskSubscription to SubscribeToTask, GetAgentCard to GetExtendedAgentCard) and new methods added (ListTasks). However, the client and server code that uses these definitions (src/a2a/client/transports/grpc.py and src/a2a/server/request_handlers/grpc_handler.py) have not been updated. This will cause runtime errors. All call sites and service implementations must be updated to match the new service definition.

Other Feedback:

• Performance: I've identified a potential performance regression in the generated a2a_pb2.pyi file related to the removal of __slots__, which I've detailed in a specific comment.
• Configuration: For future maintainability, it would be good practice to also update the configuration files used for code generation (buf.gen.yaml and scripts/generate_types.sh) to point to the specific specification version (61d1e3a6f9a5... or v0.3.0) used for this update. This ensures that regenerating the code in the future will produce consistent results.

[gemini-code-assist]

The __slots__ attribute for this class (and many others in this file, such as Task, TaskStatus, and Message) has been changed from a tuple of field names to an empty tuple (). This change effectively disables the __slots__ optimization, causing each message instance to use a __dict__ for its attributes. This will increase the memory footprint of each message object, which could be a performance concern, especially if many protobuf objects are being created in memory.

Was this change in the code generation process intentional? If it's an unintended side effect of a tool update, it would be beneficial to investigate and restore the __slots__ definitions to maintain memory efficiency.