This is the overridden Stream.fromSSEResponse static method for the bedrock SDK
When an error event happens it throws APIError.generate with the first parameter (the status code) being undefined
Which ends up creating an error class here
https://github.com/anthropics/anthropic-sdk-typescript/blob/main/src/error.ts#L101-L110
This caused us to have to write a function like this to try to figure out the status code based on the error constructor and the message
/**
* Errors that present as stream messages are inflated into APIErrors without
* status codes. AFAIK this happens only with @anthropic-ai/bedrock-sdk.
*/
const extractStatusFromError = (error: unknown): number | undefined => {
if (typeof error !== 'object' || !(error instanceof Error)) {
return
}
if (
error instanceof AnthropicClient.APIError &&
typeof error.status === 'number'
) {
return error.status
}
// for bedrock errors once streaming has started, the best way to figure out
// the status code is to look at the underlying errors name
// See: https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_InvokeModelWithResponseStream.html#API_runtime_InvokeModelWithResponseStream_ResponseSyntax
//
// NOTE(jordan): the ts typing for this omits the cause property
// @ts-ignore
const causeName = error.cause?.name
if (causeName === 'ValidationException') {
return 400
} else if (causeName === 'InternalServerException') {
return 500
} else if (causeName === 'ModelStreamErrorException') {
return 424
} else if (causeName === 'ThrottlingException') {
return 429
}
if (RE_INTERNAL_SERVER_MESSASGE.test(error.message)) {
return 500
}
if (RE_RATE_LIMIT_MESSAGE.test(error.message)) {
return 429
}
return undefined
}Lastly in the makeRequest method of the anthropics core.ts file we never see errors that happen when we make the request. This may be because we're not actually getting rate limited at the API level, but in general the more requests that could return a response that is not ok when an error happens the better. this is a lot easier to handle than pulling apart the stream for errors
https://github.com/anthropics/anthropic-sdk-typescript/blob/main/src/core.ts#L432-L451