A2A SDK interoperability validation across Rust, C#, Go, Python, Java, and JavaScript

[muscariello]

Summary

Create a CSIT interoperability program for the A2A SDKs so we can validate mixed-language compatibility across the official implementations published under a2aproject.

Why

This work is broader than the Rust SDK alone. It belongs in CSIT because the objective is cross-repository, repeatable, system-level validation of interoperability between independent SDK implementations.

The target SDK repositories are:

• agntcy/a2a-rs
• a2aproject/a2a-dotnet
• a2aproject/a2a-go
• a2aproject/a2a-python
• a2aproject/a2a-java
• a2aproject/a2a-js

Related upstream repos that may help scope or automate this work:

• a2aproject/A2A
• a2aproject/a2a-tck
• a2aproject/a2a-samples

Scope

• define an interoperability matrix covering Rust client <-> non-Rust server and non-Rust client <-> Rust server flows
• identify the shared transports that should be validated first across SDKs
• validate agent card compatibility and protocol negotiation behavior across implementations
• validate core unary flows such as send_message, get_task, list_tasks, and cancel_task
• validate streaming flows such as send_streaming_message and subscribe_to_task
• validate metadata and ServiceParams propagation where transports support it
• validate representative error mapping and failure behavior across SDK pairings
• document spec ambiguities or implementation mismatches discovered during testing
• add repeatable automation and fixtures so interoperability checks can run in CI or release validation

Per-SDK tracking

• Rust: a2aproject/a2a-rs
• C# / .NET: a2aproject/a2a-dotnet
• Go: a2aproject/a2a-go
• Python: a2aproject/a2a-python
• Java: a2aproject/a2a-java
• JavaScript: a2aproject/a2a-js

Acceptance Criteria

• CSIT contains a documented interoperability matrix for the target SDKs
• at least one shared transport and the core unary plus streaming flows are validated for each supported SDK pairing in scope
• incompatibilities are either fixed, explicitly tracked, or escalated to spec or upstream SDK issues
• contributors can rerun the interoperability checks from repo documentation and automation without reconstructing the environment manually

Notes

This epic should drive follow-up task issues in CSIT for individual SDK pairings, transport coverage, fixture setup, and CI automation.

[muscariello]

Created child issues for the first SDK-pairing split:

• Validate A2A Rust <-> C# / .NET interoperability in CSIT #162 Rust <-> C# / .NET
• Validate A2A Rust <-> Go interoperability in CSIT #163 Rust <-> Go
• Validate A2A Rust <-> Python interoperability in CSIT #164 Rust <-> Python
• Validate A2A Rust <-> Java interoperability in CSIT #165 Rust <-> Java
• Validate A2A Rust <-> JavaScript interoperability in CSIT #166 Rust <-> JavaScript