Use the A2A Python SDK for client support for A2A Remote clients. This enables A2A based agents that use gRPC or RESTful interfaces, as well as the jsonrpc support. This also simplifies creation of clients and provides simpler mechanisms to inject credentials and observability into the remote agent interactions.
PiperOrigin-RevId: 804711466
This change introduces type descriptions for the functions which convert between A2A and GenAI `Part`s. It then allows passing instances of those functions to the various A2A-related functions/classes, effectively allowing users to inject their own logic for how part conversion should occur.
The benefit of this pattern is that users can create decorators around the core `Part` conversion logic, which allows them to intercept the cases they care about while delegating the ones they do not to the core converter. This is a pattern we use a lot in the A2A Python SDK.
One example where this type of logic is useful is for extensions: this allows extension logic to, for example, interpret an A2A DataPart into a FunctionResponse using extension-specific logic.
PiperOrigin-RevId: 803186799
Before this change, other agent's reply with thought will still be inserted in the outgoing LlmRequest due to the wrong `else` statement for calling all other type of part.
This commit also refactors test_contents.py to be behavior-oriented tests, instead of implementation-oriented, and add more test cases to cover expected scenarios.
The tests are divided into the following files with different focus:
- test_contents.py: covers the basic logic of event filter;
- test_contents_branch.py: covers the behavior related to branch, which takes effect when ParallelAgent is used.
- test_contents_other_agent.py: covers the retelling behavior to include other agents' reply as context for the current agent.
- test_contents_function.py: covers the function_call/function_response rearrangement logic mainly for `LongRunningFunctionTool`.
PiperOrigin-RevId: 802759821