Claude Opus is Anthropic's flagship — top-tier reasoning, agentic behavior, 1M context window, native tool use.
curl https://oneapikey.app/v1/v1/messages \
-H "Authorization: Bearer $ONEAPIKEY_API_KEY" \
-H "X-APIMarket-Product: claude-opus-4-7" \
-H "Content-Type: application/json" \
--data '{"model":"anthropic/claude-opus-4-7","messages":[{"role":"user","content":"hi"}]}'