Developer guide

Responses compatibility

Text input and output

POST /v1/responses supports text-only requests on the public API. Authenticate with your workspace API key using the Authorization bearer header. Use a registered model route and a connected provider.

curl https://api.hardcarrx.com/v1/responses \
  -H "Authorization: Bearer $HARDCARRX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"openrouter/openai/gpt-4o-mini","input":"Hello"}'

The response has object: response, assistant output-text items, and usage counts when supplied by the provider.

Explicit compatibility limits

Streaming, tools, instructions and non-text input or modalities return HTTP 422. This is a supported subset, not full OpenAI Responses compatibility. Use chat completions for streaming. Send system context as a system message in the input array rather than instructions.

Model discovery is available in the registry guide. See the canonical API reference for the complete request schema and errors.