[DOCS] Gateway docs underspecify `CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS`

Documentation Type

Incorrect/outdated documentation

Documentation Location

https://code.claude.com/docs/en/env-vars

Section/Topic

CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS

Current Documentation

The env var reference currently says:

CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS | Set to 1 to disable Anthropic API-specific anthropic-beta headers. Use this if experiencing issues like Unexpected value(s) for the anthropic-beta header when using an LLM gateway with third-party providers

The gateway guide currently says:

When using the Anthropic Messages format with Bedrock or Vertex, you may need to set environment variable CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1.

What's Wrong or Missing?

Claude Code v2.1.77 fixed this env var so it also strips beta tool-schema fields.

Current docs describe only beta-header suppression, so gateway users do not get an accurate explanation for why this setting resolves request rejections from proxies that also reject beta schema fields.

Suggested Improvement

Update the env var and LLM gateway docs to explain the full compatibility effect.

Suggested coverage:

• disables Anthropic beta headers
• strips beta-specific tool-schema fields from requests
• useful for LLM gateways and proxy layers that reject unknown beta headers or fields
• mention that this may be required even when the main issue does not mention headers explicitly

Impact

Medium - Makes feature difficult to understand

Additional Context

Affected Pages:

| Page | Context |
|------|---------|
| https://code.claude.com/docs/en/env-vars | Env var description only mentions disabling anthropic-beta headers |
| https://code.claude.com/docs/en/llm-gateway | Gateway guide recommends the env var but does not explain schema-field stripping |

Total scope: 2 pages affected

Source: Claude Code v2.1.77 release notes

Exact release entry:

Fixed CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS not stripping beta tool-schema fields, causing proxy gateways to reject requests