feat: A2A streaming execution

[Lancetnik]

Summary

This PR consolidates remote service functionality under the a2a namespace and introduces streaming support for agent execution. The changes improve code organization, enable real-time response streaming, and remove deprecated remote service implementations.

Changes

1. Remote Services Consolidation (eb8dff96e6)

• Removed the deprecated autogen/remote module (856 lines removed)
  • Deleted autogen/remote/agent.py and autogen/remote/runtime.py
  • Removed all associated tests from test/remote/
• Moved remote service files from autogen/remote/ to autogen/a2a/remote/
  • agent_service.py, errors.py, httpx_client_factory.py, protocol.py, retry.py
• Updated imports across the codebase to use the new a2a.remote namespace
• Cleaned up pyproject.toml and .github/CODEOWNERS to reflect the new structure

2. Streaming Service Support (72132ca1be)

• Refactored AgentService.__call__() to return an AsyncGenerator[ServiceResponse, None] instead of a single response
• Updated AutogenAgentExecutor.execute() to handle streaming responses:
  • Processes responses incrementally as they're generated
  • Publishes working status updates in real-time
  • Handles input requirements immediately when detected
• Enhanced protocol with ServiceResponse model supporting:
  • Streaming messages (message field)
  • Context updates (context field)
  • Input requirements (input_required field)
• Added utility functions in utils.py:
  • make_working_message() - for streaming status updates
  • make_input_required_message() - for human-in-the-loop scenarios
  • make_artifact() - for final artifact creation
• Expanded test coverage in test/a2a/test_executor.py (175 new lines)
• Cleaned up test/a2a/test_parsing.py (removed 63 lines of redundant code)

3. AgentService Streaming Execution Refinement (f99fc6362d)

• Simplified AgentService streaming logic (9 insertions, 15 deletions)
• Improved code clarity and maintainability in the streaming execution flow

Benefits

1. Better Code Organization: All A2A-related remote functionality is now consolidated under autogen/a2a/remote/
2. Real-time Updates: Clients can now receive incremental updates as agents process requests
3. Improved UX: Streaming enables better user experience with immediate feedback
4. Reduced Codebase: Removed ~700 lines of deprecated code and tests
5. Cleaner Architecture: Simplified service interface with async generators

Testing

• Existing tests updated to work with new streaming interface
• New comprehensive tests added in test/a2a/test_executor.py
• All tests passing with the new streaming implementation

Migration Notes

• Code using autogen.remote should migrate to autogen.a2a.remote
• AgentService now returns an async generator - consumers should iterate over responses
• AutogenAgentExecutor automatically handles streaming, no changes needed for executor users

Files Changed

• 25 files changed: 167 insertions(+), 863 deletions(-)
• Key files:
  • autogen/a2a/remote/agent_service.py - Streaming implementation
  • autogen/a2a/agent_executor.py - Streaming executor integration
  • autogen/a2a/remote/protocol.py - Enhanced protocol models
  • autogen/a2a/utils.py - New utility functions
  • test/a2a/test_executor.py - Expanded test coverage

[Lancetnik]

Need to verify changes correctness with real-world samples before merge

[Lancetnik]

https://github.com/a2aproject/a2a-inspector

[codecov]

Codecov Report

❌ Patch coverage is 81.81818% with 10 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
autogen/a2a/remote/agent_service.py	64.28%	5 Missing ⚠️
autogen/a2a/remote/__init__.py	77.77%	2 Missing ⚠️
autogen/a2a/utils.py	83.33%	1 Missing and 1 partial ⚠️
autogen/a2a/agent_executor.py	90.90%	0 Missing and 1 partial ⚠️

Files with missing lines	Coverage Δ
autogen/a2a/__init__.py	83.33% <100.00%> (ø)
autogen/a2a/client.py	66.07% <100.00%> (-1.39%)	⬇️
autogen/a2a/errors.py	100.00% <100.00%> (ø)
autogen/a2a/httpx_client_factory.py	82.60% <100.00%> (ø)
autogen/a2a/remote/errors.py	66.66% <ø> (ø)
autogen/a2a/remote/httpx_client_factory.py	91.30% <ø> (ø)
autogen/a2a/remote/protocol.py	100.00% <100.00%> (ø)
autogen/a2a/remote/retry.py	46.15% <ø> (ø)
autogen/a2a/agent_executor.py	87.17% <90.90%> (+0.33%)	⬆️
autogen/a2a/remote/__init__.py	77.77% <77.77%> (ø)
... and 2 more

... and 19 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.