Claude Code 2.1.280-2.1.283 ships four releases in a week with exact model governance and Bedrock IAM
Between September 23 and 25 Anthropic shipped Claude Code 2.1.280 through 2.1.283, making Opus 5.5 the new default Opus model and introducing exact-version model allow/deny lists plus cross-account Bedrock IAM roles.
AI.jp.net reported on September 26 that Anthropic shipped four Claude Code point releases — 2.1.280, 2.1.281, 2.1.282, and 2.1.283 — between September 23 and 25. The headline change is making Opus 5.5 the new default Opus model and bringing the server-side Auto-mode classifier to direct Anthropic API connections, so third-party providers and telemetry-off setups now start in Auto mode by default.
On the management side, a new availableModelsMatch setting of "exact" restricts an entry in availableModels to only the exact version it names, so new models stay blocked until an admin adds them. A companion deniedModels setting blocks specific models outright even when availableModels would permit them. Bedrock-routed deployments gain upstream STS IAM role assumption — including cross-account and per-developer session options — along with the ability to attach an Amazon Bedrock guardrail ID and version to every request, with Anthropic requiring the policy to be applied to all Bedrock upstreams or none. Claude Code also adds a /doctor prompt-audit command that scans CLAUDE.md files, skills, agents, and commands for prompting patterns written for older models.
On security, 2.1.283 closes a Windows PowerShell path that could delete drive roots and other folders PowerShell’s own Remove-Item refuses to touch via cmd /c rd, rmdir, del, or erase, and now fails closed if a nested value in managed sandbox settings is invalid. A new optional gateway hint header, x-claude-code-prompt-id, lets LLM gateways group requests that served one user prompt.