[DOCS] Environment variables page missing ANTHROPIC_BETAS env var

[coygeek]

Documentation Type

Missing documentation (feature not documented)

Documentation Location

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

Section/Topic

Environment variables reference table

Current Documentation

No documentation currently exists for ANTHROPIC_BETAS. The env-vars page lists a comprehensive table of environment variables but does not include ANTHROPIC_BETAS. The related but distinct CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS variable is documented on the LLM gateway page, but it serves the opposite purpose (disabling betas rather than enabling them).

What's Wrong or Missing?

Changelog v2.1.78 fixed ANTHROPIC_BETAS being silently ignored when using Haiku models. The fix confirms this is a supported environment variable, but users cannot discover it from the documentation.

Users who want to enable specific Anthropic API beta features when using Claude Code have no documented mechanism to do so. The ANTHROPIC_BETAS variable presumably accepts beta feature header values (comma-separated), but without documentation users cannot know the correct format or available values.

Suggested Improvement

Add an entry to the env-vars table:

Variable	Description
ANTHROPIC_BETAS	Comma-separated list of Anthropic API beta feature headers to enable (e.g., beta-feature-1,beta-feature-2). Applied to all API requests.

Add a note clarifying the relationship with CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS (which disables Claude Code's own experimental betas, separate from API beta headers).

Impact

Medium - Makes feature difficult to understand

Additional Context

Affected Pages:

Page	Context
https://code.claude.com/docs/en/env-vars	Environment variables reference table
https://code.claude.com/docs/en/llm-gateway	Documents CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS (related but distinct)

Total scope: 2 pages affected

Source: Changelog v2.1.78

Fixed ANTHROPIC_BETAS environment variable being silently ignored when using Haiku models

[coygeek]

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Issue #35632 Verification

Title: [DOCS] Environment variables page missing ANTHROPIC_BETAS env var
Issue Date: 2026-03-18
Verification Date: 2026-04-01
Status: RESOLVED

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Issue Summary

This issue reports that the Claude Code environment-variables documentation did not document ANTHROPIC_BETAS, leaving users without current guidance on how to add Anthropic API beta headers in Claude Code or how that setting differs from CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS.

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Verification Results

Claim 1: The env-vars page is missing ANTHROPIC_BETAS

Status: RESOLVED

At https://code.claude.com/docs/en/env-vars, line 17: "ANTHROPIC_BETAS" and "Comma-separated list of additional anthropic-beta header values to include in API requests."

Verdict: The current environment-variables table now includes ANTHROPIC_BETAS directly and describes what it does.

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Claim 2: The docs do not explain the expected format for ANTHROPIC_BETAS

Status: RESOLVED

At https://code.claude.com/docs/en/env-vars, line 17: "Comma-separated list of additional anthropic-beta header values to include in API requests."

At https://platform.claude.com/docs/en/api/beta-headers, lines 83-87: "To use multiple beta features in a single request, include all feature names in the header separated by commas:" and "anthropic-beta: feature1,feature2,feature3"

Verdict: The current docs now document the comma-separated format on the Claude Code page and link to the platform beta-header reference that shows the same comma-separated syntax.

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Claim 3: The docs should distinguish ANTHROPIC_BETAS from CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS

Status: RESOLVED

At https://code.claude.com/docs/en/env-vars, line 17: "ANTHROPIC_BETAS" is documented as adding "additional anthropic-beta header values" to API requests.

At https://code.claude.com/docs/en/env-vars, line 70: "CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS" is documented as stripping "Anthropic-specific anthropic-beta request headers and beta tool-schema fields" from API requests.

At https://code.claude.com/docs/en/llm-gateway, line 37: "When using the Anthropic Messages format with Bedrock or Vertex, you may need to set environment variable CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1."

Verdict: The current docs now document both variables with distinct purposes: ANTHROPIC_BETAS adds extra beta headers, while CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS removes experimental beta headers for gateway-compatibility scenarios. That distinction addresses the relationship concern raised in the issue.

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Current State

Claim	Status
env-vars includes ANTHROPIC_BETAS	RESOLVED
The docs explain the ANTHROPIC_BETAS format	RESOLVED
The docs distinguish ANTHROPIC_BETAS from CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS	RESOLVED

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Suggested Fix

N/A - issue has been resolved.

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References

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

• Lines 17-17: Documents ANTHROPIC_BETAS as a comma-separated list of additional anthropic-beta header values.

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

• Lines 70-70: Documents CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS as stripping Anthropic-specific beta headers and beta tool-schema fields.

• URL: https://code.claude.com/docs/en/llm-gateway

• Lines 37-37: Gives a current usage case for CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1 with gateway configurations.

• URL: https://platform.claude.com/docs/en/api/beta-headers

• Lines 83-87: Shows that multiple beta features are passed in a single comma-separated anthropic-beta header.

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Conclusion & Recommendation

Primary Concern: The issue reported that Claude Code users could not discover or understand the ANTHROPIC_BETAS environment variable from the current documentation.

Resolution Status: RESOLVED

Recommendation: CLOSE

The current docs now list ANTHROPIC_BETAS, explain its purpose and comma-separated format, and document the separate role of CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS. The documentation gap described in the issue is no longer present.

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