Claude Code

Claude Code can connect to an LLM gateway through ANTHROPIC_BASE_URL and a bearer token. SnapGen exposes POST /v1/messages and model discovery for this workflow.

Anthropic documents gateway connectivity but does not officially support routing Claude Code to non-Claude models. SnapGen currently converts Claude Messages requests to its GPT routes; retest after major Claude Code upgrades.

Prerequisites

Install Claude Code and confirm claude --version works.
Create a SnapGen API key and add prepaid balance.
Choose a current text model, such as gpt-5.4-mini or gpt-5.5.

Configure the current shell

export ANTHROPIC_BASE_URL="https://api.snapgen.org"
export ANTHROPIC_AUTH_TOKEN="$SNAPGEN_API_KEY"
export CLAUDE_CODE_ENABLE_GATEWAY_MODEL_DISCOVERY=1

Use ANTHROPIC_AUTH_TOKEN, not ANTHROPIC_API_KEY. SnapGen expects Authorization: Bearer ...; Claude Code sends that header for ANTHROPIC_AUTH_TOKEN.

Verify the gateway

Test the Messages endpoint before starting Claude Code.

curl "$ANTHROPIC_BASE_URL/v1/messages" \
  -H "Authorization: Bearer $ANTHROPIC_AUTH_TOKEN" \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{
    "model": "gpt-5.4-mini",
    "max_tokens": 16,
    "messages": [{"role": "user", "content": "Reply with OK."}]
  }'

A successful response has type: "message" and text under content[0].text.

Start Claude Code

claude --model gpt-5.4-mini

Run /status inside Claude Code. Confirm that the Anthropic base URL is https://api.snapgen.org and the credential source is ANTHROPIC_AUTH_TOKEN.

Persist the configuration

Add the gateway variables to the env object in ~/.claude/settings.json:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.snapgen.org",
    "ANTHROPIC_AUTH_TOKEN": "sk-xxxx",
    "CLAUDE_CODE_ENABLE_GATEWAY_MODEL_DISCOVERY": "1"
  }
}

Prefer a shell secret manager or managed settings for production teams. Do not put the key in a repository’s .claude/settings.json.

Troubleshooting

The model is missing from /model

Set CLAUDE_CODE_ENABLE_GATEWAY_MODEL_DISCOVERY=1, restart Claude Code, and confirm that GET /v1/models returns the ID.

A new Claude Code version sends unsupported fields

Update the gateway when available. As a temporary diagnostic, set CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1 and retry.

Requests return 401

Confirm the key is active and assigned to ANTHROPIC_AUTH_TOKEN. A key in ANTHROPIC_API_KEY is sent through x-api-key, which SnapGen does not use.

Overview

Development Tools

SDKs

Prerequisites

Configure the current shell

Verify the gateway

Start Claude Code

Persist the configuration

Troubleshooting

​Prerequisites

​Configure the current shell

​Verify the gateway

​Start Claude Code

​Persist the configuration

​Troubleshooting

Prerequisites

Configure the current shell

Verify the gateway

Start Claude Code

Persist the configuration

Troubleshooting