Epic: Claude 5.5 models and authentication modes #119

Goal

Run oxide-code with Claude 5.5 models through every authentication method users can use today: Claude Code OAuth login, a long-lived OAuth token, an Anthropic API key, and a gateway that accepts a bearer token and custom headers. Verify the runtime features end to end against a real gateway.

Acceptance criteria

• Close every sub-issue.
• In a live gateway session, exercise streaming, tool use, preserved thinking across turns, prompt caching, /compact, and /model swaps without a 400 error.

Notes

Preserved thinking binds each thinking block to the exact request prefix. This keeps the system prompt and session context frozen for the session's lifetime, while changes are introduced as appended reminders.