A2Agent integration and compatibility testing

[yibeibingmrishi]

Hi open-vetta maintainers,

I represent A2Agent, an OpenAI- and Anthropic-compatible API gateway. The transport report in #73 suggests a useful diagnostic test case for the existing Responses-compatible adapter, without assuming the upstream failure is a client defect. We would like to verify compatibility with your existing configuration and contribute a focused PR covering:

• A placeholder configuration using the existing custom endpoint settings.
• A mock response.failed/upstream_error fixture matching the reported failure shape, with a normal streaming control.
• Documentation of surfaced errors and supported recovery behavior; any transport change would need a separate agreed scope.

Would you prefer a documentation/test-only PR or a broader integration?

Separately, after successful verification, would you consider including A2Agent wherever you document tested providers? We’ll follow your preferred wording and placement, without implying endorsement.

We can privately provide a test key with US$2 in API credits, plus technical support. This support is not conditional on merging, endorsement, or listing.

Thanks!