Claude Code Integration

Claude Code uses Anthropic API style. When integrating with CoreRouter, the key point is that the Base URL does not include /v1, and the API Key is provided via environment variables.

Prerequisites

• VS Code installed.
• Claude Code extension or available Claude Code environment installed.
• API Key created in CoreRouter console.
• Model that supports coding Agents selected.

Required Environment Variables

ANTHROPIC_BASE_URL="https://api.corerouter.cloud"
ANTHROPIC_AUTH_TOKEN="sk-xxxxxxxxxxxxxxxx"
ANTHROPIC_MODEL="claude-sonnet-4-5"

Variable	Description
ANTHROPIC_BASE_URL	CoreRouter Anthropic-compatible endpoint, without /v1
ANTHROPIC_AUTH_TOKEN	CoreRouter API Key
ANTHROPIC_MODEL	Model ID from console, adjustable as needed

VS Code Extension Configuration

If using Claude Code for VS Code, you can try configuring environment variables in VS Code user settings JSON. Different extension versions may support different configuration key names; if the settings don't take effect, use terminal environment variables as the primary configuration and launch VS Code from that terminal.

Open the command palette, execute Preferences: Open User Settings (JSON), and add:

{
  "claudeCode.environmentVariables": [
    { "name": "ANTHROPIC_BASE_URL", "value": "https://api.corerouter.cloud" },
    { "name": "ANTHROPIC_AUTH_TOKEN", "value": "sk-xxxxxxxxxxxxxxxx" },
    { "name": "ANTHROPIC_MODEL", "value": "claude-sonnet-4-5" }
  ]
}

macOS / Linux

Temporary configuration:

export ANTHROPIC_BASE_URL="https://api.corerouter.cloud"
export ANTHROPIC_AUTH_TOKEN="sk-xxxxxxxxxxxxxxxx"
export ANTHROPIC_MODEL="claude-sonnet-4-5"

Then launch VS Code from the same terminal:

code

For permanent effect, write to ~/.zshrc or ~/.bashrc:

echo 'export ANTHROPIC_BASE_URL="https://api.corerouter.cloud"' >> ~/.zshrc
echo 'export ANTHROPIC_AUTH_TOKEN="sk-xxxxxxxxxxxxxxxx"' >> ~/.zshrc
echo 'export ANTHROPIC_MODEL="claude-sonnet-4-5"' >> ~/.zshrc
source ~/.zshrc

Windows PowerShell

Temporary configuration:

$env:ANTHROPIC_BASE_URL="https://api.corerouter.cloud"
$env:ANTHROPIC_AUTH_TOKEN="sk-xxxxxxxxxxxxxxxx"
$env:ANTHROPIC_MODEL="claude-sonnet-4-5"

Then launch VS Code from the same PowerShell:

code

User-level permanent configuration:

[System.Environment]::SetEnvironmentVariable('ANTHROPIC_BASE_URL', 'https://api.corerouter.cloud', 'User')
[System.Environment]::SetEnvironmentVariable('ANTHROPIC_AUTH_TOKEN', 'sk-xxxxxxxxxxxxxxxx', 'User')
[System.Environment]::SetEnvironmentVariable('ANTHROPIC_MODEL', 'claude-sonnet-4-5', 'User')

Takes effect after reopening VS Code.

Test Connection

Please analyze the current project's directory structure and introduce the tech stack of this project.

If it can read the project and return analysis results, test Agent capabilities:

Please check if the current project has TypeScript type errors and tell me how to fix them.

Interface Address Explanation

Claude Code and OpenAI-compatible clients use different interface formats:

Tool	Base URL	API Format
Claude Code	https://api.corerouter.cloud	Anthropic Messages
Cline	https://api.corerouter.cloud/v1	OpenAI Compatible

Don't use https://api.corerouter.cloud/v1/chat/completions as Claude Code's Endpoint.

Manually Test Anthropic-compatible Endpoint

curl https://api.corerouter.cloud/v1/messages \
  -H "Authorization: Bearer $ANTHROPIC_AUTH_TOKEN" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-5",
    "max_tokens": 1024,
    "messages": [
      {"role": "user", "content": "Hello"}
    ]
  }'

If your gateway explicitly requires x-api-key authentication, use ANTHROPIC_API_KEY instead and change the Header to x-api-key: $ANTHROPIC_API_KEY.

See Anthropic Messages Integration for more raw API examples.

Call Chain

Claude Code
   -> CoreRouter
   -> New API compatibility layer
   -> Model channel
   -> AI Model

Common Issues

Environment Variables Not Taking Effect

Close all VS Code windows and re-execute code from the terminal with environment variables set. For Windows user-level environment variables, you may need to restart VS Code or the system.

API Key Invalid Error

Confirm you're using ANTHROPIC_AUTH_TOKEN, not ANTHROPIC_API_KEY. Also check if the API Key is from the CoreRouter console.

Can Connect But Tools Unavailable

Switch to a model that supports Tool Calling, Streaming, and Coding Agent, and check if CoreRouter's Anthropic-compatible forwarding is enabled.

Token Count or Auxiliary Endpoint Unavailable Error

Different versions of Claude Code may call Anthropic's auxiliary endpoints. CoreRouter primarily forwards Messages requests. If a version strongly depends on additional endpoints, compatibility issues may arise. In this case, first confirm that basic /v1/messages requests work, then consider switching Claude Code versions, using Cline, or contacting support to confirm current interface capabilities.

Should Base URL Include /v1?

Claude Code's environment variable should be https://api.corerouter.cloud. If filled as https://api.corerouter.cloud/v1, the tool may construct incorrect paths.

Security Recommendations

• Use system environment variables to save API Keys.
• Don't write API Keys into project repositories, READMEs, screenshots, or videos.
• Create a separate API Key for Claude Code and set a quota limit.