Claude Code

Tested with

Last verified: 2026-10-06 · Claude Code 2.1.289

Anthropic's official CLI, pointed at any compatible service through a custom gateway.

This page uses KunCode as an example. Replace the addresses, keys and model names with your own service's values. See placeholder conventions.

1. Install

npm

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

Homebrew

brew install --cask claude-code

Check the install:

claude --version

2. Prepare an API key

See Prepare an API key. Note two things:

• API key - usually looks like sk-...; use whatever format your provider issues
• API endpoint - your service address, e.g. https://kuncode.120403.xyz

3. Find the config file

Claude Code reads its user-level settings from:

OS	Path
macOS / Linux	~/.claude/settings.json
Windows	%USERPROFILE%\.claude\settings.json

Create the directory or file if it does not exist.

Why prefer the settings file

Besides plain environment variables, Claude Code accepts the gateway address and key in the env block of settings.json.

The advantage is that background agents pick it up too, instead of depending on the terminal that launched Claude Code.

4. Fill in the config

Open settings.json and write:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://kuncode.120403.xyz",
    "ANTHROPIC_AUTH_TOKEN": "sk-xxxxxxxx",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "deepseek-flash",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "deepseek-flash",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "deepseek-flash"
  }
}

Field reference:

Field	Meaning
ANTHROPIC_BASE_URL	Your API endpoint; the domain only, no /v1
ANTHROPIC_AUTH_TOKEN	Replace with your own API key
ANTHROPIC_DEFAULT_SONNET_MODEL	Model ID the sonnet alias actually calls
ANTHROPIC_DEFAULT_OPUS_MODEL	Model ID the opus alias actually calls
ANTHROPIC_DEFAULT_HAIKU_MODEL	Model ID the haiku alias actually calls, also used for titles and other background tasks

base URL must not include /v1

Claude Code appends /v1/messages itself, so write the domain only, e.g. https://kuncode.120403.xyz.

Why map all three aliases

Claude Code sends requests under the sonnet / opus / haiku aliases, and the main session and background tasks do not use the same one.

If your gateway only serves non-Claude models such as deepseek-flash, point all three aliases at the same model ID so no request asks for a missing model.

The model ID must exactly match what /v1/models returns:

curl https://kuncode.120403.xyz/v1/models \
  -H "Authorization: Bearer sk-xxxxxxxx"

Which credential variable

• ANTHROPIC_AUTH_TOKEN - sent as Authorization: Bearer <token>
• ANTHROPIC_API_KEY - sent as x-api-key: <key>

Use whichever your gateway reads. If unsure, try ANTHROPIC_AUTH_TOKEN first and switch on 401.

5. Verify

Start Claude Code:

claude

Then type:

/status

Check two lines:

• Anthropic base URL shows your gateway address
• Auth token or API key shows the credential you configured

Send any prompt afterwards; a normal reply means the setup works.

You can also verify with a single command:

claude -p "print hello"

6. Common settings

Pin a single model

If one model is enough, set ANTHROPIC_MODEL directly instead of mapping the aliases:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://kuncode.120403.xyz",
    "ANTHROPIC_AUTH_TOKEN": "sk-xxxxxxxx",
    "ANTHROPIC_MODEL": "deepseek-flash"
  }
}

Give the model a display name

After alias mapping, /model shows the model ID by default. Use _NAME for a friendlier label:

{
  "env": {
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "deepseek-flash",
    "ANTHROPIC_DEFAULT_SONNET_MODEL_NAME": "DeepSeek Flash"
  }
}

OPUS and HAIKU accept the same _NAME and _DESCRIPTION suffixes.

Adjust reasoning effort

Claude Code controls thinking depth through effort, with low, medium, high, xhigh and max:

{
  "env": {
    "CLAUDE_CODE_EFFORT_LEVEL": "high"
  }
}

You can also switch it for the current session with /effort.

Silence the unrecognized-model warning

If startup prints [claude-code:unrecognized_model], map the gateway model ID to itself with modelOverrides:

{
  "modelOverrides": {
    "deepseek-flash": "deepseek-flash"
  }
}

Correct the context window

When a gateway model's context window differs from the built-in value for its name, set it explicitly:

{
  "env": {
    "CLAUDE_CODE_MAX_CONTEXT_TOKENS": "200000"
  }
}

Use your model's real window.

7. Troubleshooting

For a systematic walkthrough by status code, see Errors and troubleshooting.

Symptom	Cause	Fix
401 Unauthorized	Key not applied, or wrong credential variable	Check /status; try ANTHROPIC_AUTH_TOKEN and ANTHROPIC_API_KEY the other way round
404 Not Found	ANTHROPIC_BASE_URL includes a path	Use the domain only, without /v1 or /v1/messages
Unknown model	An alias maps to a model the gateway does not serve	Point ANTHROPIC_DEFAULT_*_MODEL at an ID from /v1/models
Login screen keeps appearing	Credentials not read	Check the variable names and the settings.json path, then restart the terminal
Request timeout	Network or proxy	Check DNS, proxy and firewall
Model missing from /model	Not in the built-in list	Add it with ANTHROPIC_CUSTOM_MODEL_OPTION or modelOverrides

Advanced: configure with environment variables

If you would rather not write settings.json, set the values in the current terminal only:

macOS / Linux

export ANTHROPIC_BASE_URL="https://kuncode.120403.xyz"
export ANTHROPIC_AUTH_TOKEN="sk-xxxxxxxx"
export ANTHROPIC_DEFAULT_SONNET_MODEL="deepseek-flash"

Windows PowerShell

$env:ANTHROPIC_BASE_URL = "https://kuncode.120403.xyz"
$env:ANTHROPIC_AUTH_TOKEN = "sk-xxxxxxxx"
$env:ANTHROPIC_DEFAULT_SONNET_MODEL = "deepseek-flash"

To persist them, add the lines to your shell profile (~/.zshrc, ~/.bashrc) or your PowerShell $PROFILE.

The key is stored in plain text

Whether it lives in settings.json or an environment variable, the key is plain text. So:

• Never commit a file containing the key to Git
• Mask the key in screenshots

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