Claude Code 2.1.307

Claude Code 2.1.307 adds /claude-api api-version to move Claude API code to API version 2026-10-21.

It also fixes HTTP MCP tool calls being sent twice when a connection closes mid-call. Only read-only or idempotent tools, which can safely be repeated, are now retried.

On macOS, a locked login keychain gets an explanation instead of a misleading “needs authentication” message. The next run after unlocking connects without a new sign-in. MCP connections also recover from a macOS or Linux computer going to sleep while they're connecting.