Claude Code

Claude Code is an agentic terminal tool that understands codebases and accelerates development by automating routine tasks, analyzing complex code, and managing git workflows through natural language commands.

Prerequisites

• Node.js 18 or newer installed on your system (for npm installation)
• An Apertis API Key (obtain from Apertis Dashboard)

Installation

Native Installer (Recommended)

macOS / Linux / WSL:

curl -fsSL https://claude.ai/install.sh | bash

Windows PowerShell:

irm https://claude.ai/install.ps1 | iex

npm Installation

Alternatively, install via npm with Node.js 18+:

npm install -g @anthropic-ai/claude-code

Configuration

Claude Code supports custom API endpoints through environment variables. Configure the following variables to connect to Apertis API:

Variable	Value	Description
ANTHROPIC_BASE_URL	https://api.apertis.ai	Apertis API endpoint
ANTHROPIC_AUTH_TOKEN	Your Apertis API key	Authentication token
ANTHROPIC_API_KEY	"" (empty string)	Must be explicitly empty
API_TIMEOUT_MS	3000000	Request timeout (optional)

Important

The ANTHROPIC_API_KEY must be explicitly set to an empty string, not just unset. This prevents conflicts with any existing Anthropic configuration.

Method 1: Settings File (Recommended)

Edit or create ~/.claude/settings.json:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.apertis.ai",
    "ANTHROPIC_AUTH_TOKEN": "your_apertis_api_key",
    "ANTHROPIC_API_KEY": "",
    "API_TIMEOUT_MS": "3000000"
  }
}

Replace your_apertis_api_key with your actual API key from Apertis Dashboard.

Method 2: Project-Level Configuration

For project-specific settings, create .claude/settings.local.json in your project root:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.apertis.ai",
    "ANTHROPIC_AUTH_TOKEN": "your_apertis_api_key",
    "ANTHROPIC_API_KEY": ""
  }
}

note

Do not use standard .env files; the native installer doesn't read them. Use the settings files or shell environment variables instead.

Method 3: Environment Variables

macOS / Linux

Add to your shell profile (~/.bashrc, ~/.zshrc, etc.):

export ANTHROPIC_BASE_URL="https://api.apertis.ai"
export ANTHROPIC_AUTH_TOKEN="your_apertis_api_key"
export ANTHROPIC_API_KEY=""
export API_TIMEOUT_MS="3000000"

Then reload your shell:

source ~/.zshrc  # or source ~/.bashrc

To remove the configuration and revert to defaults:

unset ANTHROPIC_BASE_URL
unset ANTHROPIC_AUTH_TOKEN
unset ANTHROPIC_API_KEY
unset API_TIMEOUT_MS

Also remove the corresponding lines from your shell profile file, then reload your shell.

Windows Command Prompt

setx ANTHROPIC_BASE_URL https://api.apertis.ai
setx ANTHROPIC_AUTH_TOKEN your_apertis_api_key
setx ANTHROPIC_API_KEY ""
setx API_TIMEOUT_MS 3000000

To remove the configuration:

reg delete "HKCU\Environment" /v ANTHROPIC_BASE_URL /f
reg delete "HKCU\Environment" /v ANTHROPIC_AUTH_TOKEN /f
reg delete "HKCU\Environment" /v ANTHROPIC_API_KEY /f
reg delete "HKCU\Environment" /v API_TIMEOUT_MS /f

Windows PowerShell

[System.Environment]::SetEnvironmentVariable('ANTHROPIC_BASE_URL', 'https://api.apertis.ai', 'User')
[System.Environment]::SetEnvironmentVariable('ANTHROPIC_AUTH_TOKEN', 'your_apertis_api_key', 'User')
[System.Environment]::SetEnvironmentVariable('ANTHROPIC_API_KEY', '', 'User')
[System.Environment]::SetEnvironmentVariable('API_TIMEOUT_MS', '3000000', 'User')

To remove the configuration:

[System.Environment]::SetEnvironmentVariable('ANTHROPIC_BASE_URL', $null, 'User')
[System.Environment]::SetEnvironmentVariable('ANTHROPIC_AUTH_TOKEN', $null, 'User')
[System.Environment]::SetEnvironmentVariable('ANTHROPIC_API_KEY', $null, 'User')
[System.Environment]::SetEnvironmentVariable('API_TIMEOUT_MS', $null, 'User')

After configuration, open a new terminal window and run claude to activate the settings.

Launch and Verify

Navigate to your project directory and start Claude Code:

cd your-project-directory
claude

Grant file access permissions when prompted.

Verify Connection

Run the status command inside Claude Code to verify your configuration:

/status

You should see output similar to:

Auth token: ANTHROPIC_AUTH_TOKEN
Anthropic base URL: https://api.apertis.ai

Model Configuration

Setting a Default Model

You can set a default model using the ANTHROPIC_MODEL environment variable:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.apertis.ai",
    "ANTHROPIC_AUTH_TOKEN": "your_apertis_api_key",
    "ANTHROPIC_API_KEY": "",
    "ANTHROPIC_MODEL": "claude-opus-4-5-20251101"
  }
}

Subscription Plan Users

If you are using a subscription plan, add the code: prefix to the model ID:

{
  "env": {
    "ANTHROPIC_MODEL": "code:claude-opus-4-5-20251101"
  }
}

Selecting Models in Claude Code

After configuration, you can view and select your custom model inside Claude Code:

1. Launch Claude Code in your terminal:

   claude

2. Use the /model command to see available models:

   /model

3. Your custom model ID will appear in the list. Select it to start using the configured model.

Model Tier Mappings

You can also customize which models are used for each tier (opus, sonnet, haiku):

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.apertis.ai",
    "ANTHROPIC_AUTH_TOKEN": "your_apertis_api_key",
    "ANTHROPIC_API_KEY": "",
    "API_TIMEOUT_MS": "3000000",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "claude-opus-4-5-20251101",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "claude-sonnet-4.5",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "claude-haiku-4.5"
  }
}

Tool Use Requirement

The selected models must support tool use capabilities. Claude Code requires tool use for file operations, terminal commands, and code editing. All Claude models available through Apertis support tool use.

For the latest available models, check the Model List.

GitHub Actions Integration

You can use Claude Code in your CI/CD pipelines with GitHub Actions:

- name: Run Claude Code
  uses: anthropics/claude-code-action@v1
  with:
    anthropic_api_key: ${{ secrets.APERTIS_API_KEY }}
  env:
    ANTHROPIC_BASE_URL: https://api.apertis.ai
    ANTHROPIC_API_KEY: ""

Store your Apertis API key as a GitHub secret named APERTIS_API_KEY.

Troubleshooting

Configuration Not Taking Effect

• Close all Claude Code windows and open a new terminal
• Run claude again to restart with new settings
• Validate your JSON syntax using an online JSON validator

Verify Configuration

Check your current version:

claude --version

Inside Claude Code, run /status to verify the API endpoint configuration.

Connection Issues

If you encounter connection errors:

1. Verify your API key is correct at Apertis Dashboard
2. Ensure the base URL is set to https://api.apertis.ai
3. Confirm ANTHROPIC_API_KEY is explicitly set to empty, not just unset
4. Check your network connection and firewall settings

Tool Use Failures

If Claude Code fails to execute file operations or commands:

• Ensure your selected model supports tool use capabilities
• Use the default Claude models which all support tool use
• Check that you have granted the necessary file access permissions

Context Limitations

For complex tasks with large codebases:

• Use models with 128k+ context windows
• Consider breaking large operations into smaller tasks

Environment Variables Reference

Variable	Description
ANTHROPIC_BASE_URL	Custom API endpoint URL (https://api.apertis.ai)
ANTHROPIC_AUTH_TOKEN	Your Apertis API key
ANTHROPIC_API_KEY	Must be explicitly empty ("")
ANTHROPIC_MODEL	Default model ID (use code: prefix for subscription plans)
API_TIMEOUT_MS	API request timeout in milliseconds (3000000)
ANTHROPIC_DEFAULT_OPUS_MODEL	Default model for opus tier
ANTHROPIC_DEFAULT_SONNET_MODEL	Default model for sonnet tier
ANTHROPIC_DEFAULT_HAIKU_MODEL	Default model for haiku tier
HTTP_PROXY / HTTPS_PROXY	Network proxy (if required)

Features

Claude Code provides powerful capabilities including:

• Code Understanding: Analyzes your entire codebase context
• Automated Refactoring: Helps refactor and improve code quality
• Git Workflow: Manages commits, branches, and pull requests
• Bug Fixing: Identifies and helps fix issues in your code
• Documentation: Generates documentation and comments
• Testing: Helps write and run tests

Related Resources

• Apertis API Documentation
• Model List
• API Keys Management
• Claude Code Official Documentation