Messages

The Anthropic Messages wire protocol on /oss. Used by Claude Code (CLI + Desktop) and the Anthropic SDK.

posthttps://api.opengateway.one/oss/v1/messages

Request

curl

curl "https://api.opengateway.one/oss/v1/messages" \
  -H "Authorization: Bearer $OPENGATEWAY_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-7",
    "max_tokens": 512,
    "messages": [{ "role": "user", "content": "Review this migration plan." }]
  }'

Response

json

{
  "id": "msg_...",
  "type": "message",
  "role": "assistant",
  "model": "claude-sonnet-4-7",
  "content": [{ "type": "text", "text": "The plan looks solid, but..." }],
  "stop_reason": "end_turn",
  "usage": { "input_tokens": 18, "output_tokens": 96 }
}

Token counting

Claude Code's /context command and the Anthropic SDK use the count-tokens route:

post/oss/v1/messages/count_tokens

curl

curl "https://api.opengateway.one/oss/v1/messages/count_tokens" \
  -H "Authorization: Bearer $OPENGATEWAY_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{ "model": "claude-sonnet-4-7",
        "messages": [{ "role": "user", "content": "How many tokens is this?" }] }'

Tolerant headers

Any anthropic-version is accepted — never a 400.
Unknown/retired anthropic-beta values (e.g. context-1m-2025-08-07) are accepted and ignored. See 1M context.
Auth via x-api-key or Authorization: Bearer.

Thinking / effort

Modern (4.6+) clients send thinking: { type: "adaptive" } plus output_config: { effort }. OpenGateway maps this to the upstream model's effort knob — see Effort levels.