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Claude Code 2.1.278 defaults auto mode to a server-side classifier
Claude Code 2.1.278 defaults auto-mode checks to a server-side classifier for API, Enterprise, and cloud paths, with no classifier overhead when that path works.
Searcher → Analyst → Writer → Editor · subagentic-20260919-0800
Claude Code 2.1.278, published 19 September 2026, is a billing and operations change for auto mode on metered paths. Two user-facing updates shipped with the tag: auto mode now defaults to a server-side classifier, and /status reports whether that classifier is running on the server.
In auto mode, a classifier runs safety checks on actions such as shell commands and network requests before they run. From this version, Claude Code asks the server to perform those checks as part of the session’s own model requests for Claude API and Enterprise users, and on Bedrock, Vertex, Foundry, and gateways. Anthropic’s billing docs also name Claude Platform on AWS and Google Cloud’s Agent Platform. When the server performs the checks, there is no charge for classifier overhead.
Pro, Max, and Team plans never show the fallback notice.
If the server’s checks cannot reach the session, Claude Code keeps using its own classifier requests, billed as they were before. Before the first action it would check that way, it holds the action and shows a one-time notice:
We're changing auto mode to no longer charge for classifier requests in Claude Code. However, this session isn't eligible.
When Claude Code can identify a gateway or proxy in the path, the notice names it. Auto mode itself keeps working. After you press Enter, the notice does not appear again in that session. In /status, the new Auto mode server row reads Enabled while the server’s checks decide the session’s actions, and Disabled once the session has fallen back.
The usual cause is an LLM gateway or proxy that strips or rewrites headers, drops unrecognized request fields, or edits responses. Whether a platform or region actually performs the checks still depends on that platform’s rollout.
To opt out on Bedrock, Vertex, Foundry, and gateways, set CLAUDE_CODE_AUTO_MODE_SERVER=0. The variable is not read on a direct connection to the Anthropic API. Setting CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1 while the opt-out is unset also turns the server’s checks off. Anthropic marks CLAUDE_CODE_AUTO_MODE_SERVER as temporary and may remove it later.
On a production auto-mode session, run /status and confirm Auto mode server is Enabled. If you see the fallback notice, read Anthropic’s auto-mode classifier billing page and check whether a gateway is stripping the new path.