Claude Code 2.1.316
By Steven Van ·
Opus 4.8 fast mode is removed on November 30, and the release adds a subagent effort setting, an ultrathink switch and gateway budget options.
Fast mode for Opus 4.8 is deprecated in Claude Code 2.1.316, and the release also adds several environment variables and Claude apps gateway options. The changes are listed in the changelog.
Fast mode deprecation
Fast mode for Opus 4.8 was deprecated on October 30, 2026, and will be removed on November 30, 2026. After removal, fast mode requests on Opus 4.8 return an error. They do not fall back to standard Opus 4.8. The changelog says to migrate to Opus 5.5.
New environment variables
- CLAUDE_CODE_DISABLE_ULTRATHINK turns the ultrathink keyword off.
- CLAUDE_CODE_SUBAGENT_EFFORT sets the effort level subagents run at when nothing else names one, instead of inheriting the session's.
- CLAUDE_CODE_DISABLE_LOOPED_CROSS_CERT_DROP keeps system cross-certificates that certify each other in a loop, for servers whose private CA needs one.
Claude apps gateway
- Pooled group budgets give a group's members one shared monthly budget, on top of each member's own limit. It is set with pooled_budget on the spend limits admin API.
- managed.policy_mode: layered applies every policy that matches a developer, each merged over the ones listed below it, rather than only the first match.
- guardrail.input_tagging on Bedrock upstreams wraps prompts in the input tags that an Amazon Bedrock guardrail's prompt attacks filter needs. The all_messages_and_system setting also tags the system prompt.
Claude Code
Anthropic's agentic coding tool — Claude in your terminal, IDE, desktop app and browser, reading and editing your codebase, running commands, opening pull requests and working on tasks in the cloud.
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