Claude Code Environment Variables Complete Guide: Fix AWS Bedrock Compatibility Error with Just 1 Setting

Author's Note: A deep dive into all 60+ Claude Code environment variables, focusing on how CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS fixes the anthropic-beta header error on third-party platforms.

When using Claude Code to connect to AWS Bedrock, Google Vertex AI, or other third-party LLM gateways, you've likely run into this error: "Unexpected value(s) for the anthropic-beta header". This happens because Claude Code sends Anthropic-specific experimental Beta headers by default, which third-party platforms like AWS Bedrock don't recognize.

The solution is just a one-line setting: CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1.

But Claude Code's environment variables go far beyond just this one—the official documentation lists over 60 environment variables, covering authentication, model selection, performance tuning, feature toggles, and more. This article will systematically break down these variables to help you quickly locate and resolve any Claude Code configuration issues.

Core Value: By the end of this post, you'll master the full Claude Code environment variable system, be able to quickly fix AWS Bedrock/Vertex AI compatibility issues, and learn how to optimize your Claude Code experience and costs through environment variables.

Key Claude Code Environment Variables

Claude Code's 60+ environment variables can be grouped into 6 main categories. Here are the core variables you should care about:

Two Ways to Set Claude Code Environment Variables

Method 1: Shell Environment Variables (Temporary)

Set these in your terminal before starting Claude Code. This only applies to the current session:

export CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1
export ANTHROPIC_API_KEY="your-api-key"
claude

Method 2: settings.json Configuration (Permanent)

Configure the env field in ~/.claude/settings.json. These are automatically loaded every time you start:

{
  "env": {
    "CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS": "1",
    "ANTHROPIC_API_KEY": "your-api-key"
  }
}

🎯 Pro Tip: For settings you want to keep long-term (like API keys or platform compatibility fixes), use the settings.json method so you don't have to manually export them every time. If you're using an API key from a third-party platform like APIYI (apiyi.com), just configure it here.

Claude Code Environment Variables: Solving AWS Bedrock Compatibility Issues

Deep Dive into CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS

This is the star of the show. When you use Claude Code through third-party gateways like AWS Bedrock, Google Vertex AI, or LiteLLM, Claude Code automatically adds Anthropic's experimental beta flags to the request headers. For example:

anthropic-beta: prompt-caching-scope-2026-01-05,advanced-tool-use-2025-11-20

These beta flags are features specific to the direct Anthropic API. Third-party platforms like AWS Bedrock don't recognize them, which leads to this error:

Error: Unexpected value(s) for the anthropic-beta header

The Solution:

# Option 1: Via Shell command
export CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1

# Option 2: In settings.json
{
  "env": {
    "CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS": "1"
  }
}

By setting this to 1, Claude Code stops sending these experimental beta headers, making it compatible with all third-party platforms.

Known Issues & Temporary Workarounds

According to GitHub Issues, some versions of Claude Code (post-2.1.18) have an issue where this environment variable isn't fully effective—certain new beta headers (like advanced-tool-use-2025-11-20) might still be sent even if CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1 is set.

If you're still running into trouble, try these additional steps:

• Downgrade Claude Code: Roll back to a known stable version like 2.1.68.
• Use LiteLLM Gateway: LiteLLM offers an anthropic_beta_headers_config.json configuration file, allowing you to fine-tune which beta headers are forwarded.
• Set DISABLE_PROMPT_CACHING: Disabling prompt caching can help avoid beta headers related to prompt-caching-scope.

# Full compatibility settings
export CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1
export DISABLE_PROMPT_CACHING=1

Claude Code Environment Variables: Complete Reference

Category 1: Authentication & API Configuration

This is the most fundamental category, controlling how Claude Code connects to the API service:

🎯 Note for Third-Party Platform Users: When using third-party API platforms like APIYI (apiyi.com), you need to set both ANTHROPIC_API_KEY and ANTHROPIC_BASE_URL. Claude Code will prioritize the API key in your environment variables, even if you're logged into an Anthropic subscription account.

Category 2: Model Selection & Configuration

Controls which model Claude Code uses and its behavioral parameters:

Category 3: Platform Compatibility & Gateway Configuration

These variables are specifically designed to resolve compatibility issues between Claude Code and various cloud platforms or LLM gateways:

Category 4: Feature Toggles

Disable specific features using the DISABLE_ or CLAUDE_CODE_DISABLE_ prefix:

Category 5: Context & Performance Management

Controls how Claude Code manages the context window and resource usage:

🎯 Performance Tip: If you notice Claude Code frequently compressing context during long conversations, you can set CLAUDE_AUTOCOMPACT_PCT_OVERRIDE to a lower value (like 50). This triggers compaction earlier, which can help reduce information loss. These environment variable configurations are also fully supported when invoking models via APIYI (apiyi.com).

Claude Code Environment Variables Quick Start

Minimalist Example: Configuring Claude Code to Connect to Third-Party API Platforms

# Start Claude Code after setting environment variables in the terminal
export ANTHROPIC_API_KEY="sk-your-api-key"
export ANTHROPIC_BASE_URL="https://vip.apiyi.com/v1"
export CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1
claude

{
  "env": {
    "ANTHROPIC_API_KEY": "sk-your-api-key",
    "ANTHROPIC_BASE_URL": "https://vip.apiyi.com/v1",
    "CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS": "1",
    "CLAUDE_CODE_MAX_OUTPUT_TOKENS": "32000",
    "CLAUDE_AUTOCOMPACT_PCT_OVERRIDE": "80",
    "DISABLE_TELEMETRY": "1"
  },
  "permissions": {
    "allow": ["Read", "Glob", "Grep"],
    "deny": []
  }
}

{
  "env": {
    "CLAUDE_CODE_USE_BEDROCK": "1",
    "CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS": "1",
    "DISABLE_PROMPT_CACHING": "1",
    "ANTHROPIC_SMALL_FAST_MODEL_AWS_REGION": "us-east-1"
  }
}

{
  "env": {
    "CLAUDE_CODE_USE_FOUNDRY": "1",
    "ANTHROPIC_FOUNDRY_BASE_URL": "https://my-resource.services.ai.azure.com/anthropic",
    "ANTHROPIC_FOUNDRY_API_KEY": "your-foundry-key",
    "CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS": "1"
  }
}

Tip: If you don't want to mess with complex AWS Bedrock or Azure configurations, you can use the full range of Claude models directly via APIYI (apiyi.com). Just set the API key and Base URL—no need to deal with cloud platform authentication or compatibility issues.

FAQ

Summary

Key takeaways for Claude Code environment variables:

1. Fixing AWS Bedrock Errors: Set CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1 to disable experimental beta headers. This one-line fix resolves the "Unexpected value(s) for the anthropic-beta header" error.
2. 60+ Environment Variables across 6 Categories: Authentication, model selection, platform compatibility, feature toggles, context management, and other settings.
3. Two Configuration Methods: Shell export (temporary) and settings.json (permanent). We recommend using settings.json for persistent configurations.
4. Simplified Setup via Third-Party Platforms: By using a unified API platform like APIYI (apiyi.com), you only need to set two variables: ANTHROPIC_API_KEY and ANTHROPIC_BASE_URL. This bypasses complex cloud platform authentication and beta header compatibility issues.

We recommend using APIYI (apiyi.com) for a quick Claude Code setup. The platform provides free credits and a unified interface, helping you avoid the various compatibility pitfalls often found in AWS Bedrock or Vertex AI configurations.

📚 References

1. Claude Code Official Docs – Environment Variables: Full list of environment variables and descriptions.

   • Link: code.claude.com/docs/en/env-vars
   • Description: The authoritative reference for all 60+ environment variables.

2. Claude Code Official Docs – Settings: Configuration scopes and settings.json specifications.

   • Link: code.claude.com/docs/en/settings
   • Description: Understanding the four-tier configuration system: Managed, User, Project, and Local.

3. Claude Code Official Docs – Amazon Bedrock: AWS Bedrock integration guide.

   • Link: code.claude.com/docs/en/amazon-bedrock
   • Description: Bedrock-specific configurations and troubleshooting common issues.

4. GitHub Issue #22893 – DISABLE_EXPERIMENTAL_BETAS not fully effective: Community bug report.

   • Link: github.com/anthropics/claude-code/issues/22893
   • Description: Learn about known limitations and temporary workarounds for this environment variable.

5. LiteLLM – Claude Code Beta Headers Management: Beta header filtering at the gateway level.

   • Link: docs.litellm.ai/docs/tutorials/claude_code_beta_headers
   • Description: Fine-grained beta header control when using the LiteLLM gateway.

Author: APIYI Tech Team
Technical Discussion: Feel free to discuss your Claude Code configuration experiences in the comments. For more tutorials, visit the APIYI Documentation Center at docs.apiyi.com.