Open Responses

Open Responses is an open-source specification for multi-provider, interoperable LLM interfaces inspired by the OpenAI Responses API. It defines a shared request/response model, streaming semantics, and tool invocation patterns so clients and providers can exchange structured inputs and outputs in a consistent shape.

At a high level, the spec centers on:

• An agentic loop that lets models emit tool calls, receive results, and continue.
• Items as the atomic unit of context, with clear state machines and streaming updates.
• Semantic streaming events (not raw text deltas) for predictable, provider-agnostic clients.
• Extensibility for provider-specific tools and item types without breaking the core schema.

What's in this repo

• Full specification: public/openapi/openapi.json
• Website documentation content (source): src/pages
• Compliance tests: bin/compliance-test.ts

Compliance testing

This repo includes an interactive compliance tester in the docs site (/compliance) and a CLI runner for faster local iteration and CI (bin/compliance-test.ts).

Web UI

The interactive compliance tester is available at https://www.openresponses.org/compliance.

CLI

Run the same compliance suite as the web UI from the command line. For example:

bun run test:compliance --base-url http://localhost:8000/v1 --api-key $API_KEY

Filter to specific tests:

bun run test:compliance --base-url http://localhost:8000/v1 --api-key $API_KEY --filter basic-response,streaming-response

For all flags:

bun run test:compliance --help