Sonnet 3.7 not working

• name: openrouter/anthropic/claude-3.7-sonnet
  edit_format: diff
  extra_params:
  model: openai/claude-3.7-sonnet
  api_key: n/a
  api_base: http://localhost:3000/v1

• name: openrouter/anthropic/claude-3.7-sonnet-thought
  edit_format: diff
  extra_params:
  model: openai/claude-3.7-sonnet-thought
  api_key: n/a
  api_base: http://localhost:3000/v1

• name: claude-3-7-sonnet-20250219
  edit_format: diff
  extra_params:
  model: openai/claude-3.7-sonnet
  api_key: n/a
  api_base: http://localhost:3000/v1

• name: claude-3-7-sonnet-20250219-thought
  edit_format: diff
  extra_params:
  model: openai/claude-3.7-sonnet-thought
  api_key: n/a
  api_base: http://localhost:3000/v1

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This doesn't work. Getting error: litellm.APIError: APIError: OpenAIException - Error code: 500 - {'error': 'Streaming error'}

SEARCH/REPLACE block

ERROR: Error in streaming mode: {"name":"Error","message":"Request Failed: 400 {"error":{"message":"Model is not supported for this request.","param":"model","code":"model_not_supported","type":"invalid_request_error"}}\n"}

[nazzysar]

+1, same issue. Tried various different naming variations, and it does not work.

[bitnom]

This issue is due to a change github made. A few hours after the Sonnet 3.7 release, copilot's premium model servers were taken offline for maintenance, temporarily disabling the new models for everyone. Once I realized they were back online I ran a test and encountered this same issue.

Hypothesis

A change to the vscode LM API is now requiring additional parameter(s) or steps, effectively restricting premium model usage to the copilot extension. It could be more benign than this but it's my first guess.

Initial Thought

WTF

Deeper

I don't abuse the API. roocode and aider don't do anything crazy. Until either github makes a much better version of copilot or Anthropic stops price gouging, there can be only one response: commence the hackening

Please assist in analysis.

Hmm okay I will try to reverse engineer it. Probably should be easy. Most likely because of the thinking tokens stuff

@lutzleonhardt do you have a RE environment guide or something?

[nazzysar]

As extra context: https://github.com/ericc-ch/copilot-api this solution still works with 3.7 sonnet as normal. So this is something related to the VSCode LM API maybe?

[bitnom]

As extra context: ericc-ch/copilot-api this solution still works with 3.7 sonnet as normal. So this is something related to the VSCode LM API maybe?

If that still works then maybe I was wrong. Thanks, I'll check it out.

[hnipps]

VSCode is adding this header x-onbehalf-extension-id: poai.copilot-proxy/1.0.1 to requests and requests succeed if I remove this header.

[nazzysar]

VSCode is adding this header x-onbehalf-extension-id: poai.copilot-proxy/1.0.1 to requests and requests succeed if I remove this header.

Can you give some more details/guidance on how we can remove this header and make it permanent? @hnipps

[hnipps]

Use mitmproxy to intercept calls from VSCode and remove the offending header.

How to route VSCode network requests to mitmproxy.

[lutzleonhardt]

VSCode is adding this header x-onbehalf-extension-id: poai.copilot-proxy/1.0.1 to requests and requests succeed if I remove this header.

Can you give some more details/guidance on how we can remove this header and make it permanent? @hnipps

OK, but I think this means Github Copilot does not want their plugins to use Sonnet 3.7 yet, right?

[nazzysar]

Looks like this is consistent throughout most other VSCode LM API extensions. Cline and RooCode is having the same issue. Looks like it's something from Github's side not wanting 3.7 to be exposed yet to extensions.

[bitnom]

See the updated README: https://github.com/ericc-ch/copilot-api/blob/master/README.md

He got a warning email from github about usage and then said...

The spoofing wasn't enough. Just faking a few headers maybe just wasn't enough. There were also some sort of machine and session id that I wasn't able to replicate. I mostly suspect these headers are used for telemetry.

However, x-onbehalf-extension-id does not appear in his repo. So I added the header in my fork but it did not resolve the error. You're all welcome to have a look. It's easier to experiment with copilot-api.

I also started decompiling the copilot extension but it's a huge bundle that won't fit in LLM context. There's a tool to clean it (The name escapes me) but I haven't tried yet. Probably best to mitm and see what's happening.

I'm sure it can be defeated with extra work but tinker at your own risk since it's become clear enough that they don't like it.