Claude Code 2.1.316: Ultrathink, Pooled Budgets, and What Changed in October

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Claude Code 2.1.316 shipped on October 31, 2026 with a broad set of changes: `CLAUDE_CODE_DISABLE_ULTRATHINK` to turn ultrathink off, pooled group budgets for the Claude apps gateway, layered `managed.policy_mode`, and fixes across shell handling, MCP tools, subagents, and VS Code. Here is what changed and what it means if you run Claude Code.

New capabilities in 2.1.316

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Ultrathink can now be disabled

2.1.316 adds `CLAUDE_CODE_DISABLE_ULTRATHINK`, an environment variable that turns the `ultrathink` keyword off entirely. In VS Code, `ultrathink` now runs its turn at `xhigh` effort and shows in a rainbow in the chat box, matching the terminal behavior. This gives teams a way to gate the most expensive reasoning mode when cost or latency matters.

Pooled group budgets for the Claude apps gateway

The gateway gained pooled group budgets: a single monthly budget that a group's members share, on top of each member's own individual limit. It is configured with `pooled_budget` on the spend limits admin API. Also added is `managed.policy_mode: layered`, where every matching policy applies and merges over the ones listed below it, rather than only the first matching policy winning.

Other additions

• `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_CODE_SUBAGENT_EFFORT` sets the effort level subagents run at when nothing else names one, instead of inheriting the session's effort.
• Guardrail input tagging on Claude apps gateway Bedrock upstreams wraps prompts in the tags an Amazon Bedrock guardrail's prompt-attacks filter needs.
• VS Code gained sign-in to a Claude apps gateway from the chat panel, with no terminal needed.
• Cloud sessions gained a form card for MCP server forms and a "Catching up…" indicator when switching back to a session.

What changed behavior

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• Fast mode deprecated for Opus 4.8 as of October 30, 2026, removed November 30, 2026. After removal, fast-mode requests on Opus 4.8 error instead of falling back. Anthropic says to migrate to Opus 5.5 to keep the speedup.
• Server-managed settings for Team and Enterprise logins now apply without an approval prompt, and a stored copy that doesn't verify is refused.
• Auto mode: an `autoMode.allow` list without `"$defaults"` no longer removes the built-in rule on scheduled-task prompts.
• Cloud session network secrets: Enterprise members can now add and delete them on their own cloud environments, not just view them.

Notable fixes

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• Shell commands left running when Claude Code exits on macOS and Linux (e.g., credentials refused or a cloud session archived) are now cleaned up.
• Bash aliases with line breaks and functions starting with a dash are no longer garbled in the Bash tool.
• Subagents that inherited a parent's model no longer move to the main model when a background job wakes them.
• `SubagentStop` hooks now run once when a subagent finishes, instead of about twice a minute.
• WebFetch and WebSearch in Cowork cloud sessions now fail after 300 seconds instead of hanging on a stalled response.
• VS Code: fixed missing Effort slider, Ultracode switch, and model name when the model setting has the `[1m]` tag; fixed chat links written as full Windows paths not opening.

Bottom line

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2.1.316 is primarily a reliability and governance release. If you run Claude Code with subagents, MCP servers, or self-hosted runners, the cleanup of stuck shell processes, the subagent model-inheritance fix, and the SubagentStop hook fix are the most practical changes. The ultrathink disable and pooled group budgets matter most for teams managing cost across many users.

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