BetaManagedAgentsEventParamsOfUserMessage helper omits required Type field

[ryanlitalien]

Bug

The helper function BetaManagedAgentsEventParamsOfUserMessage() in betasessionevent.go does not set the required Type field on BetaManagedAgentsUserMessageEventParams, resulting in a 400 Bad Request with events[0].type: Field required when calling POST /v1/sessions/{id}/events.

Reproduction

client.Beta.Sessions.Events.Send(ctx, sessionID, anthropic.BetaSessionEventSendParams{
    Events: []anthropic.BetaManagedAgentsEventParamsUnion{
        anthropic.BetaManagedAgentsEventParamsOfUserMessage(
            []anthropic.BetaManagedAgentsUserMessageEventParamsContentUnion{{
                OfText: &anthropic.BetaManagedAgentsTextBlockParam{
                    Text: "hello",
                    Type: anthropic.BetaManagedAgentsTextBlockTypeText,
                },
            }},
        ),
    },
})

Returns:

400 Bad Request: {"type":"error","error":{"type":"invalid_request_error","message":"Failed to parse request: events[0].type: Field required"}}

Root cause

The helper only sets Content, not Type:

func BetaManagedAgentsEventParamsOfUserMessage(content []BetaManagedAgentsUserMessageEventParamsContentUnion) BetaManagedAgentsEventParamsUnion {
    var userMessage BetaManagedAgentsUserMessageEventParams
    userMessage.Content = content  // ✅
    // userMessage.Type is never set ❌
    return BetaManagedAgentsEventParamsUnion{OfUserMessage: &userMessage}
}

Compare with the other helpers which DO accept and set their type parameter:

func BetaManagedAgentsEventParamsOfUserInterrupt(type_ ...) { ... userInterrupt.Type = type_ ... }
func BetaManagedAgentsEventParamsOfUserToolConfirmation(result, toolUseID, type_ ...) { ... userToolConfirmation.Type = type_ ... }

Suggested fix

Either set the type automatically (since there's only one valid value):

func BetaManagedAgentsEventParamsOfUserMessage(content []BetaManagedAgentsUserMessageEventParamsContentUnion) BetaManagedAgentsEventParamsUnion {
    var userMessage BetaManagedAgentsUserMessageEventParams
    userMessage.Content = content
    userMessage.Type = BetaManagedAgentsUserMessageEventParamsTypeUserMessage
    return BetaManagedAgentsEventParamsUnion{OfUserMessage: &userMessage}
}

Workaround

Construct the struct directly instead of using the helper:

Events: []anthropic.BetaManagedAgentsEventParamsUnion{
    {
        OfUserMessage: &anthropic.BetaManagedAgentsUserMessageEventParams{
            Content: content,
            Type:    anthropic.BetaManagedAgentsUserMessageEventParamsTypeUserMessage,
        },
    },
},

Version

anthropic-sdk-go v1.34.0

[dinzz005]

Hey bro, are you working on this or shall i fix this??