Under the hood
A new gate controls whether a third-party MCP server classifier is enabled, defaulting on
What
A new function computes and caches whether the third-party MCP server classifier is enabled. It defaults to on, except when CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS is set and the provider isn't host-managed, or when overridden by CLAUDE_CODE_AUTO_MODE_SERVER.
Why
This gives environments that disable experimental betas, or that set a custom auto-mode server, control over whether MCP servers get classified as third-party, rather than that behavior being fixed for everyone.
Names in the bundleCLAUDE_CODE_DISABLE_EXPERIMENTAL_BETASCLAUDE_CODE_AUTO_MODE_SERVER
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Added since
A small documentation edit on Choose a permission mode touched a line naming CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS after this was published.
On Enterprise plans and accounts that use the Claude API, on [Claude Platform on AWS](/docs/en/claude-platform-on-aws), Amazon Bedrock, Google Cloud's Agent Platform, and Microsoft Foundry, and whenever you point `ANTHROPIC_BASE_URL` at an…permission-modes see the edit
Confirmed since
Anthropic's documentation has since written up CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS, on Claude Code gateway compatibility guide.
| `anthropic-beta` values sent | The subset Amazon Bedrock and Agent Platform accept | The full set described under [feature pass-through](#feature-pass-through), unless the developer sets [`CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS`](#disabl…llm-gateway-protocol see the edit
Added since
A small documentation edit on Environment variables touched a line naming CLAUDE_CODE_AUTO_MODE_SERVER after this was published.
| `CLAUDE_CODE_AUTO_MODE_SERVER` | Controls whether Claude Code asks the server to [review auto mode actions](/docs/en/permission-modes#server-side-classifier-review). When unset, Claude Code asks the server on Amazon Bedrock, Google Cloud…env-vars see the edit
Confirmed since
Anthropic's documentation has since written up CLAUDE_CODE_AUTO_MODE_SERVER, on Claude Code changelog.
* Changed auto mode on Bedrock, Vertex and Foundry to use the local classifier by default for now; set `CLAUDE_CODE_AUTO_MODE_SERVER=1` to use the platform's server-side classifierchangelog see the edit
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The finding doesn't say what the classifier does with a server once it's classified as third-party.
Anthropic's documentation agrees
Anthropic's documentation has since written up CLAUDE_CODE_AUTO_MODE_SERVER, on Claude Code changelog.
The name it cites is new in this build
New in this build: CLAUDE_CODE_AUTO_MODE_SERVER