{"name":"CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS","slug":"claude-code-disable-experimental-betas","family":"env","title":"Environment variables","noun":"environment variable","description":"Set to `1` to strip Anthropic-specific `anthropic-beta` request headers and beta tool-schema fields (such as `defer_loading` and `eager_input_streaming`) from API requests. Use this when a proxy gateway rejects requests with errors like \"Unexpected value(s) for the `anthropic-beta` header\" or \"Extra inputs are not permitted\". Standard fields (`name`, `description`, `input_schema`, `cache_control`) are preserved. [MCP tool search](\/docs\/en\/mcp#scale-with-mcp-tool-search) is disabled and all MCP tools load upfront, even when you set `ENABLE_TOOL_SEARCH`. On Claude Code v2.1.227 or later, [managed settings](\/docs\/en\/managed-settings) can keep tool search on. [Disable pre-release capabilities](\/docs\/en\/llm-gateway-protocol#disable-pre-release-capabilities) covers where the override applies","description_source":"docs","described_by":{"doc":"claude-code\/env-vars","title":"Environment variables"},"presence":{"first_seen":"2.1.138","removed_in":null,"in_current_build":true,"newest_mined":"2.1.309","builds":150,"mined_builds":150,"first_cited":{"version":"2.1.123","released_at":"2026-04-29 01:52:47","spans":3}},"aliases":[],"entries":[{"version":"2.1.286","anchor":"beta-disabled-reason-wording-changed","heading":"Clearer message when beta features are not sent to your API provider","line":"The explanation for why Anthropic's first-party beta features are withheld from a session's API provider has new wording","released_at":"2026-09-30 17:14:38","reason":"found in this entry's text"},{"version":"2.1.285","anchor":"features-gating-tools-unavailable-listing-reasons","heading":"Claude Code now says why the 'highlights' feature is unavailable","line":"When 'highlights' is unavailable, Claude Code now names the reason: provider, experimental betas turned off, model, or the API rejecting it","released_at":"2026-09-29 17:32:09","reason":"found in this entry's text"},{"version":"2.1.282","anchor":"control-protocol-thinking-display-highlights-now-fails-in","heading":"SDK requests for 'highlights' thinking display now fail in more cases","line":"SDK requests for the 'highlights' thinking display now fail on unsupported setups instead of quietly falling back","released_at":"2026-09-24 15:56:22","reason":"found in this entry's text"},{"version":"2.1.281","anchor":"claude-code-auto-mode-server-split-into-a-tri-state-user-swi","heading":"CLAUDE_CODE_AUTO_MODE_SERVER split into a tri-state user switch","line":"`CLAUDE_CODE_AUTO_MODE_SERVER` is now read as on, off or unset, so Claude Code can tell an unset variable from an explicit choice","released_at":"2026-09-23 17:01:17","reason":"found in this entry's text"},{"version":"2.1.271","anchor":"new-third-party-mcp-server-classifier-gate","heading":"New third-party MCP server classifier gate","line":"A new gate controls whether a third-party MCP server classifier is enabled, defaulting on","released_at":"2026-09-14 19:45:19","reason":"found in this entry's text, named in this entry"},{"version":"2.1.227","anchor":"tool-search-beta-header-falls-back-when-experimental-betas-a","heading":"Tool-search beta header falls back when experimental betas are turned off","line":"Turning off experimental betas now falls back to the older tool-search beta header everywhere.","released_at":"2026-08-10 20:56:57","reason":"found in this entry's text"},{"version":"2.1.220","anchor":"auto-mode-classifier-requests-now-send-a-new-beta-header","heading":"Auto-mode classifier requests now send a new beta header","line":"Auto mode's permission classifier now tags its requests with a beta marker on Anthropic-hosted sessions.","released_at":"2026-07-24 23:11:21","reason":"named in this entry, found in this entry's text"},{"version":"2.1.138","anchor":"advanced-mid-conversation-system-beta-override","heading":"Advanced Mid-Conversation System Beta Override","line":null,"released_at":"2026-05-09 05:57:28","reason":"found in this entry's text"},{"version":"2.1.123","anchor":"reduced-scope-of-claude-code-disable-experimental-betas-for-","heading":"Reduced scope of CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS for certain API betas","line":null,"released_at":"2026-04-29 01:52:47","reason":"found in this entry's text"},{"version":"2.0.45","anchor":"experimental-features-flag-check","heading":"Experimental Features Flag Check","line":null,"released_at":"2025-11-18 16:31:06","reason":"found in this entry's text"}],"entries_total":10,"docs":[{"source":"claude-code","path":"env-vars","title":"Environment variables","documented":true},{"source":"claude-code","path":"agent-sdk\/modifying-system-prompts","title":"Modifying system prompts","documented":false},{"source":"claude-code","path":"agent-sdk\/tool-search","title":"Scale to many tools with tool search","documented":false},{"source":"claude-code","path":"auto-mode-classifier-billing","title":"Auto mode classifier request charges","documented":false},{"source":"claude-code","path":"changelog","title":"Claude Code changelog","documented":false},{"source":"claude-code","path":"errors","title":"Error reference","documented":false},{"source":"claude-code","path":"llm-gateway-connect","title":"Connect Claude Code to an LLM gateway","documented":false},{"source":"claude-code","path":"llm-gateway-protocol","title":"Claude Code gateway compatibility guide","documented":false},{"source":"claude-code","path":"llm-gateway-rollout","title":"Roll out an LLM gateway for your organization","documented":false},{"source":"claude-code","path":"mcp","title":"Connect Claude Code to tools via MCP","documented":false}],"docs_total":12,"gates":[],"related":[{"name":"CLAUDE_CODE_DISABLE_1M_CONTEXT","slug":"claude-code-disable-1m-context","description":"Set to `1` to disable [1M context window](\/docs\/en\/model-config#extended-context) support. When set, 1M model variants are unavailable in the model picker, and Claude Code holds sessions on models with a native 1M window, such as [Sonnet 5.5](\/docs\/en\/model-config#sonnet-5-5-and-sonnet-5-context-window) and the Fable models, to a 200K window; see [Extended context](\/docs\/en\/model-config#extended-context) for how the hold is enforced. Useful for enterprise environments with compliance requirements. For its role in correcting the window for an unrecognized `[1m]` model ID, see [Correct the window for a gateway or custom model ID](\/docs\/en\/model-config#correct-the-window-for-a-gateway-or-custom-model-id)"},{"name":"CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING","slug":"claude-code-disable-adaptive-thinking","description":"Set to `1` to disable [adaptive reasoning](\/docs\/en\/model-config#adjust-effort-level) on Opus 4.6 and Sonnet 4.6 and fall back to the fixed thinking budget controlled by `MAX_THINKING_TOKENS`. Has no effect on [Fable models](\/docs\/en\/model-config#extended-thinking), Sonnet 5 and later, or Opus 4.7 and later, which always use adaptive reasoning"},{"name":"CLAUDE_CODE_DISABLE_ADMIN_ENV_UNION","slug":"claude-code-disable-admin-env-union","description":"Set to `1` to stop Claude Code from merging [managed settings](\/docs\/en\/managed-settings#precedence-within-the-managed-tier) `env` blocks per key across admin sources, so only the highest-priority source's whole `env` block applies, as before v2.1.223. Set it in the environment that launches Claude Code, since Claude Code ignores a copy delivered through a settings `env` block. Requires Claude Code v2.1.223 or later"},{"name":"CLAUDE_CODE_DISABLE_ADVISOR_TOOL","slug":"claude-code-disable-advisor-tool","description":"Set to `1` to disable the [advisor tool](\/docs\/en\/advisor). The `\/advisor` command becomes unavailable, any configured `advisorModel` is ignored, and the `--advisor` flag is accepted but has no effect, so existing scripts that pass it continue to work without errors"},{"name":"CLAUDE_CODE_DISABLE_AGENT_VIEW","slug":"claude-code-disable-agent-view","description":"Set to `1` to turn off [background agents and agent view](\/docs\/en\/agent-view): `claude agents`, `--bg`, `\/background`, and the on-demand supervisor. Equivalent to the [`disableAgentView`](\/docs\/en\/settings-reference#disableagentview) setting"},{"name":"CLAUDE_CODE_DISABLE_AGENTS_FLEET","slug":"claude-code-disable-agents-fleet","description":"A true value (`1`, `true`, `yes`, `on`) turns off the background-agents fleet, the same as the `disableBackgroundAgents` setting: the fleet gate that otherwise follows `tengu_slate_meadow` returns false, so `claude daemon` subcommands that need the gate stop with `'daemon' is not enabled.`, the built-in Claude agent is left out of the built-in agent list, and `claude daemon run` exits with `claude daemon: background agents disabled (ZDR\/3P\/opt-out)`."},{"name":"CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN","slug":"claude-code-disable-alternate-screen","description":"Set to `1` to disable [fullscreen rendering](\/docs\/en\/fullscreen) and use the classic main-screen renderer. The conversation stays in your terminal's native scrollback so `Cmd+f` and tmux copy mode work as usual. Takes precedence over `CLAUDE_CODE_NO_FLICKER` and the [`tui`](\/docs\/en\/settings-reference#tui) setting. You can also switch with `\/tui default`. Does not apply to background sessions opened from [agent view](\/docs\/en\/agent-view), which always use fullscreen rendering"},{"name":"CLAUDE_CODE_DISABLE_ARTIFACT","slug":"claude-code-disable-artifact","description":"Set to `1` to turn off the [Artifact](\/docs\/en\/artifacts) tool, which publishes session output as a private web page on claude.ai. Once you set it, no settings file turns the tool back on. To turn the tool off from a settings file instead, set [`enableArtifact`](\/docs\/en\/settings-reference#enableartifact) to `false`; the deprecated [`disableArtifact`](\/docs\/en\/settings-reference#disableartifact) key also turns it off"},{"name":"CLAUDE_CODE_DISABLE_ATTACHMENTS","slug":"claude-code-disable-attachments","description":"Set to `1` to disable attachment processing. File mentions with `@` syntax are sent as plain text instead of being expanded into file content"},{"name":"CLAUDE_CODE_DISABLE_ATTRIBUTION_BASELINE_REUSE","slug":"claude-code-disable-attribution-baseline-reuse","description":null}],"url":"https:\/\/changelogs.core-directive.com\/reference\/env\/claude-code-disable-experimental-betas","family_url":"https:\/\/changelogs.core-directive.com\/reference\/env.json"}