Claude Code v2.1.316 deprecates Opus 4.8 fast mode and adds pooled group budgets

Anthropic published Claude Code v2.1.316 on GitHub on October 31, 2026. The release deprecates fast mode for Opus 4.8 as of October 30, 2026, and removes it on November 30, 2026. After removal, fast mode requests on Opus 4.8 return an error instead of falling back to standard Opus 4.8. Anthropic says users should migrate to Opus 5.5 to keep the speedup.

The release also adds pooled group budgets to the Claude apps gateway. A group can now share one monthly budget among its members, on top of each member’s own limit. Admins set it with pooled_budget on the spend limits admin API.

Other changes include CLAUDE_CODE_SUBAGENT_EFFORT, which sets the effort level subagents run at when nothing else names one, and CLAUDE_CODE_DISABLE_ULTRATHINK, which turns off the ultrathink keyword. The gateway gains managed.policy_mode: layered, so every matching policy applies, each merged over the ones below it. It also now checks each model a request names against availableModels, deniedModels and models, and a request naming a blocked model returns a 400 error that names the field. For Team and Enterprise logins, server-managed settings now apply without an approval prompt, and a stored copy that does not verify is refused. A fix stops --restricted sessions from uploading files outside the working directories when a Read allow rule covered them.

Why it matters

Teams that depend on Opus 4.8 fast mode will get failed requests after November 30 rather than a quiet fallback, which could break builds and scripts. The stricter model checks may also reject existing requests that name restricted models. Shared group budgets give admins a new way to control spend across a team.

What to do

Find workflows that set fast mode on Opus 4.8 and plan a move to Opus 5.5 before November 30. Review gateway policies and model lists for requests that name blocked models. Confirm budget and pricing details on Anthropic’s site before changing settings.