[BUG] Anthropic disabled OAuth tokens for third-party apps

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

OAuth tokens (sk-ant-oat*) no longer work for API access — paying subscribers locked out

As of ~Feb 20 2026, OAuth workspace tokens generated via claude setup-token (prefix sk-ant-oat01-*) are rejected by the API:

• Via x-api-key: "invalid x-api-key"
• Via Authorization: Bearer: "OAuth authentication is currently not supported."

This means Max/Pro subscribers paying $200/month cannot use their tokens for third-party integrations. Only console API keys (sk-ant-api03-*) with separate pay-per-use billing work.

No prior notice was given. This is a breaking change that affects anyone building on top of Claude outside the official apps.

No 1M context window for $200/month, no use of the API Key for developing third party apps. This is the last month I pay for your subscription, there are already much better options out there.

What Should Happen?

Use our payed limits for any aplicación of the model

Error Messages/Logs

- Via `x-api-key`: `"invalid x-api-key"`
- Via `Authorization: Bearer`: `"OAuth authentication is currently not supported."`

Steps to Reproduce

Use the API with the OAuth token

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.51

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_