Claude Code v2.1.316 adds subagent effort control, pooled budgets, and fixes for orphaned shells

Claude Code v2.1.316 is out. It adds a handful of environment knobs for controlling subagent behavior and policy merging, extends the Claude apps gateway with shared budgets and Bedrock guardrail tagging, and fixes a long list of shell, hook, and model-fallback bugs.

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 effort.
• 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.

Gateway changes

Pooled group budgets are now available on the Claude apps gateway: one monthly budget that a group's members share, on top of each member's own limit. Set it with pooled_budget on the spend limits admin API.

managed.policy_mode: layered makes every policy that matches a developer apply, each merged over the ones listed below it — instead of only the first matching policy.

For Bedrock upstreams, guardrail.input_tagging wraps prompts in the input tags an Amazon Bedrock guardrail's prompt-attacks filter needs. all_messages_and_system also tags the system prompt.

Deprecation: Opus 4.8 fast mode

Fast mode for Opus 4.8 is deprecated as of October 30, 2026, and will be removed on November 30, 2026. After removal, fast mode requests on Opus 4.8 return an error and do not fall back to standard Opus 4.8. To keep the speedup, migrate to Opus 5.5.

Notable fixes

• Shell commands are no longer left running on macOS/Linux when Claude Code exits on its own (e.g. credentials refused, cloud session archived).
• Bash aliases with line breaks (except Git Bash) and functions whose names start with a dash are no longer garbled or dropped in the Bash tool's shell.
• Bash scripts started from the Bash tool no longer stop after the first command when SHELLOPTS is exported.
• PowerShell hooks now block on exit code 2 when the command begins with a type cast, param, using, or an attribute.
• Network requests no longer hang when a compressed response is cut off or corrupted.
• sonnet, opus, and haiku on Vertex AI and Amazon Bedrock now switch to an older model mid-session instead of erroring when the newest model isn't available to the account or region.
• The gateway now checks every model a request names against availableModels, deniedModels, and models; a blocked model returns a 400 naming the field.
• claude auth login runs where managed settings require a gateway and shows the gateway sign-in in a terminal.
• --restricted sessions no longer upload files from outside the working directories when a Read allow rule covered them.
• Prompts containing invisible characters send cleaned on the first Enter; commands still wait for review.
• Sub-agents that inherited a parent sub-agent's model no longer jump to the main model when a background job or message wakes them.
• A managed autoMode.allow list without "$defaults" keeps the built-in exceptions from host --settings, /permissions, or /auto-mode-setup.
• Cloud sessions and cloud scheduled tasks are marked failed when auto mode stops a turn because the server returned no safety verdict.
• claude -p text output now says why auto mode stopped a turn when a background agent is still running.
• CLAUDE_CODE_AUTO_MODE_SERVER=1 is honored in host-app sessions (e.g. Claude Desktop) behind a proxy or LLM gateway with experimental betas off.
• Plugin MCP headersHelper scripts no longer get a corrupted CLAUDE_PLUGIN_ROOT and server URL when a credential-named env var is set to a switch value like 1.
• The SDK register_repo_root control request loads the CLAUDE.md of a directory outside the working directory when CLAUDE_CODE_ADDITIONAL_DIRECTORIES_CLAUDE_MD=1 is set.
• The Artifact tool no longer shows ? for self-level artifact DB access rules, and quotes them back when refusing a republish that would drop them.
• /model <id> warns when the model isn't recognized by this version and auto-compact will assume a 200K context window.
• Grep and Glob return instead of hanging when the search process is killed at timeout without exiting.

If you run subagents with a different effort level than your main session, or you administer a shared gateway, this release is worth pulling.