What caused the switch? Also, are you still trying to use Claude models in OpenCode?
You can access anthropic models with subscription pricing via a copilot license.
Pretty sure that's against TOS.
Edit: it's not. https://github.blog/changelog/2026-01-16-github-copilot-now-...
They must be eating insane amounts of $$$ for this. I wouldn't expect it to last
No, Claude on GitHub Copilot is billed at 3X the usage rate of the other models e.g. GPT-5.4 and you get an extremely truncated context window.
See https://models.dev for a comparison against the normal "vanilla" API.