Question about getting usage from stream response

[hyperlink]

Hello!

I have a question about and would appreciate any help.

According to Anthropic's docs the message delta is supposed to have a usage with the message_delta event.

event: message_delta data: {"type": "message_delta", "delta": {"stop_reason": "end_turn", "stop_sequence":null, "usage":{"output_tokens": 15}}}

When I look the usage (on .messageDelta type) it appears to always be nil.

Any ideas why that would happen?

[fumito-ito]

Hi @hyperlink. Thanks for the feedback.

When I look the usage (on .messageDelta type) it appears to always be nil.

I have checked your point, and the Anthropic documentation explains that the response to a message_delta event has the following type.

event: message_delta
data: {"type": "message_delta", "delta": {"stop_reason": "end_turn", "stop_sequence":null, "usage":{"output_tokens": 15}}}

However, when I checked the actual response, I found the following

event: message_delta
data: {"type": "message_delta", "delta": {"stop_reason": "end_turn", "stop_sequence":null}, "usage":{"output_tokens": 15}}

The difference between the two is whether usage is under delta or not. Perhaps the documentation is wrong, but we are reserving our response at this time to contact Anthropic.

[hyperlink]

Yes @fumito-ito I also see the same the console. Appears to be a bug in their documentation!

[hyperlink]

I reported the issue to Anthropic's support. I have it fixed locally and I'll try to create a PR.

[fumito-ito]

Fixed by #8