`_meta` field is not included at serialization

[Nemtecl]

Description

When using field_meta it doesn't uses alias at runtime.
When not provided field_meta is always added at serialization

I think by_alias=True is missing when using model_dump

Step to reproduce

With field_meta

connection.sessionUpdate(
    SessionNotification(
        sessionId="random_id",
        update=AgentMessageChunk(
            sessionUpdate="agent_message_chunk",
            content=TextContentBlock(type="text", text="demo"),
            field_meta={"foo": "bar"}
        ),
    )
)

field_meta is not included in the json

Without field_meta

connection.sessionUpdate(
    SessionNotification(
        sessionId="random_id",
        update=AgentMessageChunk(
            sessionUpdate="agent_message_chunk",
            content=TextContentBlock(type="text", text="demo"),
        ),
    )
)

field_meta is always null

[PsiACE]

Thank you for pointing that out. I'll fix it.

[Nemtecl]

@PsiACE Thanks for the fix ! Do you have an idea on when there will be a new version of the package with the fix included 🙏 ?

[PsiACE]

@PsiACE Thanks for the fix ! Do you have an idea on when there will be a new version of the package with the fix included 🙏 ?

Thanks for the note.
I’ll likely update the SDK to ACP 0.6.3 next to keep it aligned with the latest protocol version.
I plan to spend some time preparing the release today, so it should be available within a few hours.

[PsiACE]

I’ve released v0.6.3 — it includes the fix, completes union discriminators (type, sessionUpdate, outcome), and stabilizes StdioMcpServer.type; thanks again for flagging it. @Nemtecl