Hello!

As the title says, I was wondering how did OpenCode manage to obtain OAuth credentials from Anthropic, which are then used to log into the API and enable Claude Code usage.

My apologies if this has already been answered but I haven't been able to find any documentation about this anywhere and the Anthropic documentation doesn't mention any procedure to obtain OAuth credentials.

I'm asking because OpenCode seems to be the only third-party tool that supports using a Claude Pro/Max subscription (other tools like Cline delegate authentication and usage to the Claude Code CLI itself and don't have direct API access).