Experimental Features Flag Check / Claude Code v2.0.45

What: New internal function to check if experimental beta features should be enabled based on deployment environment

Details:

Experimental features are automatically enabled for firstParty and foundry deployments
Can be disabled with CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=true environment variable
Evidence: mq4() at line 86382

The build it came inv2.0.45

18 Nov 2025 · 10 entries, this one is #2.

Either side of it

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Names in this entry

envCLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS
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 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 can keep tool search on. Disable pre-release capabilities covers where the override applies

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