Agent Breaking Changes_

← Claude Code

Claude Code v2.1.278

2026-09-19 · official notes

Summary

• Changed auto mode for Claude API and Enterprise users, and on Bedrock, Vertex, Foundry and gateways, to default to the server-side classifier, which does not charge for classifier overhead (CLAUDECODE
• Added an Auto mode server row to /status showing whether this session's auto mode classifier runs on the server

Full notes

## What's changed

- Changed auto mode for Claude API and Enterprise users, and on Bedrock, Vertex, Foundry and gateways, to default to the server-side classifier, which does not charge for classifier overhead (`CLAUDE_CODE_AUTO_MODE_SERVER=0` opts out on Bedrock, Vertex, Foundry and gateways); warns on billed fallback. See https://code.claude.com/docs/en/auto-mode-classifier-billing
- Added an `Auto mode server` row to `/status` showing whether this session's auto mode classifier runs on the server