Claude Code

Install and verify

The official recommendation is the native install script, no Node required; the npm route still works but is no longer recommended. After installing, print the version to confirm.

# macOS / Linux / WSL (recommended)
curl -fsSL https://claude.ai/install.sh | bash

# Windows PowerShell (recommended)
irm https://claude.ai/install.ps1 | iex

# npm route (still works, no longer recommended)
npm install -g @anthropic-ai/claude-code

# Verify
claude --version

Find the config file

Claude Code reads its config from settings.json. Put it in the user-level file to reuse across all projects, or place one in a project root to apply only there (project-level takes precedence over user-level).

Windows

%USERPROFILE%\.claude\settings.json

macOS

~/.claude/settings.json

Linux

~/.claude/settings.json

Project-level

<project-root>/.claude/settings.json

Write the config

In the env block of settings.json, set three fields: endpoint, auth token and default model. The address uses the native protocol — no /v1 needed, Claude Code fills in the request path itself.

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.xylemnode.com",
    "ANTHROPIC_AUTH_TOKEN": "sk-your-key",
    "ANTHROPIC_MODEL": "gpt-5.6-sol"
  }
}

Or use system env vars

If you'd rather not edit a file, set the same three as system environment variables — same effect. On Windows, run setx and reopen the terminal.

# Windows (PowerShell / CMD)
setx ANTHROPIC_BASE_URL "https://api.xylemnode.com"
setx ANTHROPIC_AUTH_TOKEN "sk-your-key"
setx ANTHROPIC_MODEL "gpt-5.6-sol"

# macOS / Linux
export ANTHROPIC_BASE_URL="https://api.xylemnode.com"
export ANTHROPIC_AUTH_TOKEN="sk-your-key"
export ANTHROPIC_MODEL="gpt-5.6-sol"

Clear the onboarding gate before the first run

A fresh Claude Code install reads .claude.json in your user directory and checks its onboarding flag before anything else. With that flag missing it ignores the custom endpoint you just configured and dials api.anthropic.com directly, so the very first run fails with Unable to connect to Anthropic services and Failed to connect to api.anthropic.com (403 or ERR_BAD_REQUEST) even though the address and the key are both correct. Adding the flag by hand clears the gate: create the file as shown if it doesn't exist, or merge that one line into the top-level object and leave the rest untouched, then run claude again. Note that .claude.json is not the settings.json from the earlier step — it sits alongside the .claude directory, and global state like this is silently ignored when written into settings.json.

Windows

%USERPROFILE%\.claude.json

macOS / Linux

~/.claude.json

{
  "hasCompletedOnboarding": true
}

Launch and test

From your project directory run claude and send a simple message to confirm; use /status to see the current endpoint and model.

claude

# Non-interactive quick check
claude -p "Reply with OK only"