Claude Code Setup

Configure Claude Code to use MR Coder as your API endpoint by setting a few environment variables.

This works for the Claude Code CLI, the VS Code extension, and any other tool that respects the ANTHROPIC_AUTH_TOKEN and ANTHROPIC_BASE_URL environment variables.

Prerequisites

An active MR Coder account with an API key (format: sk-mr-auth-...). Generate one from your MR Coder dashboard.

Claude Code CLI or the Claude Code VS Code Extension installed.

Environment Variables

Claude Code respects these environment variables. Set them to route requests through MR Coder instead of the default Anthropic API.

Variable	Value
`ANTHROPIC_AUTH_TOKEN`	`sk-mr-auth-XXXXXXXXXXXXXXXXXXXXX`
`ANTHROPIC_BASE_URL`	`https://api.mr-coder.io`
`ANTHROPIC_MODEL`	`anthropic:claude-opus-4-6`
`ANTHROPIC_DEFAULT_OPUS_MODEL`	`anthropic:claude-opus-4-6`
`ANTHROPIC_DEFAULT_SONNET_MODEL`	`anthropic:claude-sonnet-4-6`
`ANTHROPIC_DEFAULT_HAIKU_MODEL`	`anthropic:claude-haiku-5-5`
`CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC`	`1`

Shell Configuration File

Add the environment variables to your shell configuration file. They will load automatically every time you open a terminal:

macOS / Linux — Bash

Add to ~/.bashrc or ~/.profile:

Bash

export ANTHROPIC_AUTH_TOKEN="sk-mr-auth-XXXXXXXXXXXXXXXXXXXXX"
export ANTHROPIC_BASE_URL="https://api.mr-coder.io"
export ANTHROPIC_MODEL="anthropic:claude-opus-4-6"
export ANTHROPIC_DEFAULT_OPUS_MODEL="anthropic:claude-opus-4-6"
export ANTHROPIC_DEFAULT_SONNET_MODEL="anthropic:claude-sonnet-4-6"
export ANTHROPIC_DEFAULT_HAIKU_MODEL="anthropic:claude-haiku-5-5"
export CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC="1"

macOS — Zsh

Add to ~/.zshrc:

Bash

export ANTHROPIC_AUTH_TOKEN="sk-mr-auth-XXXXXXXXXXXXXXXXXXXXX"
export ANTHROPIC_BASE_URL="https://api.mr-coder.io"
export ANTHROPIC_MODEL="anthropic:claude-opus-4-6"
export ANTHROPIC_DEFAULT_OPUS_MODEL="anthropic:claude-opus-4-6"
export ANTHROPIC_DEFAULT_SONNET_MODEL="anthropic:claude-sonnet-4-6"
export ANTHROPIC_DEFAULT_HAIKU_MODEL="anthropic:claude-haiku-5-5"
export CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC="1"

Linux

Add to ~/.bashrc, ~/.profile, or ~/.bash_profile:

Bash

export ANTHROPIC_AUTH_TOKEN="sk-mr-auth-XXXXXXXXXXXXXXXXXXXXX"
export ANTHROPIC_BASE_URL="https://api.mr-coder.io"
export ANTHROPIC_MODEL="anthropic:claude-opus-4-6"
export ANTHROPIC_DEFAULT_OPUS_MODEL="anthropic:claude-opus-4-6"
export ANTHROPIC_DEFAULT_SONNET_MODEL="anthropic:claude-sonnet-4-6"
export ANTHROPIC_DEFAULT_HAIKU_MODEL="anthropic:claude-haiku-5-5"
export CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC="1"

After adding, restart your terminal or run source ~/.bashrc (or equivalent) to load the variables.

VS Code Extension (settings.json)

Add the environment variables to your VS Code settings. Use global settings for all projects, or .vscode/settings.json in a specific project.

Global: Ctrl+Shift+P→ “Preferences: Open User Settings (JSON)”

JSON

{
  "terminal.integrated.env.linux": {
    "ANTHROPIC_AUTH_TOKEN": "sk-mr-auth-XXXXXXXXXXXXXXXXXXXXX",
    "ANTHROPIC_BASE_URL": "https://api.mr-coder.io",
    "ANTHROPIC_MODEL": "anthropic:claude-opus-4-6",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "anthropic:claude-opus-4-6",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "anthropic:claude-sonnet-4-6",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "anthropic:claude-haiku-5-5",
    "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC": "1"
  },
  "terminal.integrated.env.osx": {
    "ANTHROPIC_AUTH_TOKEN": "sk-mr-auth-XXXXXXXXXXXXXXXXXXXXX",
    "ANTHROPIC_BASE_URL": "https://api.mr-coder.io",
    "ANTHROPIC_MODEL": "anthropic:claude-opus-4-6",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "anthropic:claude-opus-4-6",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "anthropic:claude-sonnet-4-6",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "anthropic:claude-haiku-5-5",
    "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC": "1"
  },
  "terminal.integrated.env.windows": {
    "ANTHROPIC_AUTH_TOKEN": "sk-mr-auth-XXXXXXXXXXXXXXXXXXXXX",
    "ANTHROPIC_BASE_URL": "https://api.mr-coder.io",
    "ANTHROPIC_MODEL": "anthropic:claude-opus-4-6",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "anthropic:claude-opus-4-6",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "anthropic:claude-sonnet-4-6",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "anthropic:claude-haiku-5-5",
    "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC": "1"
  }
}

This ensures the variables are available in VS Code's integrated terminal where Claude Code runs.

.env File

Create a .env file in your project root:

Bash

ANTHROPIC_AUTH_TOKEN=sk-mr-auth-XXXXXXXXXXXXXXXXXXXXX
ANTHROPIC_BASE_URL=https://api.mr-coder.io
ANTHROPIC_MODEL=anthropic:claude-opus-4-6
ANTHROPIC_DEFAULT_OPUS_MODEL=anthropic:claude-opus-4-6
ANTHROPIC_DEFAULT_SONNET_MODEL=anthropic:claude-sonnet-4-6
ANTHROPIC_DEFAULT_HAIKU_MODEL=anthropic:claude-haiku-5-5
CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC=1

Ensure .env is in your .gitignore to avoid committing your API key.

Local Configuration Pattern

For team environments where you don't want to commit credentials, use a local-only config file that's excluded from version control:

JSON

{
  "env": {
    "ANTHROPIC_AUTH_TOKEN": "sk-mr-auth-XXXXXXXXXXXXXXXXXXXXX",
    "ANTHROPIC_BASE_URL": "https://api.mr-coder.io",
    "ANTHROPIC_MODEL": "anthropic:claude-opus-4-6",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "anthropic:claude-opus-4-6",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "anthropic:claude-sonnet-4-6",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "anthropic:claude-haiku-5-5",
    "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC": "1"
  }
}

Name it .claude/settings.local.json (or similar) and add it to .gitignore. Your tooling or scripts can then reference the env block when starting Claude Code.

Why Use MR Coder?

Keep API Keys Secure

Your MR Coder API key stays local. No cloud credentials exposed to third-party services.

Drop-In Replacement

Same environment variables as the official Anthropic API. No code changes needed.

Flexible Configuration

Choose between CLI flags, shell config, VS Code settings, or .env files.

Works With Any Client

Any tool that supports ANTHROPIC_AUTH_TOKEN and ANTHROPIC_BASE_URL works out of the box.

Troubleshooting

401 Authentication Error

Verify your API key is correct and hasn't expired. Check that ANTHROPIC_AUTH_TOKEN is set (not ANTHROPIC_API_KEY) and the value starts with sk-mr-auth-.

Claude Code still hitting api.anthropic.com

Make sure ANTHROPIC_BASE_URL is set in the same terminal session where you run Claude Code. Check with: echo $ANTHROPIC_BASE_URL (macOS/Linux) or echo %ANTHROPIC_BASE_URL% (Windows).

VS Code extension not picking up settings

VS Code extensions run in their own process. Use the terminal.integrated.env settings (shown above) or launch Claude Code from a terminal where the variables are already set.

Need an API Key?

Log in to your MR Coder account and generate an API key from the dashboard. If you don't have an account yet, sign up here.