Messages (Anthropic)

POST /v1/messages speaks the Anthropic Messages shape, so an Anthropic client can route through LunaRoute by changing its base URL and key.

curl https://gw.lunaroute.com/v1/messages \
  -H "LUNAROUTE-API-KEY: $LUNAROUTE_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{
    "model": "glm-5.3",
    "max_tokens": 256,
    "messages": [{"role": "user", "content": "hello"}]
  }'

POST /v1/messages/count_tokens counts input tokens for the same shape.

Auth note

Use the LUNAROUTE-API-KEY header. Authorization: Bearer lr_… and x-api-key: lr_… are also accepted when the value is lr_-prefixed — which means an Anthropic client configured with x-api-key works unchanged.

Claude Code passes the header through ANTHROPIC_CUSTOM_HEADERS; the CLI’s lunaroute setup claude-code wires this for you, along with the MCP server.

LunaRoute-specific behavior

Background model variants and project attribution work exactly as in Chat completions. Both /v1/messages and /v1/responses route to the same models as /v1/chat/completions.