Architecture

High-level request pipeline and provider selection.

Request pipeline (simplified)

1. Auth (recommended: Authorization: Bearer <access-key>)
2. Provider selection
3. DSL execution in phases (defaults then selected match)
4. Upstream call and response strategy (passthrough / JSON map / SSE parse)
5. Optional usage extraction and pricing

Provider selection priority

1. x-onr-provider: <provider> header (force)
2. models.yaml routing (per model round-robin)

DSL phases (execution engine)

Typical phases:

• upstream_config: base URL
• auth: header shape and optional OAuth exchange
• request: header/query/JSON patching, request mapping
• upstream: set upstream path/query
• response: passthrough / resp_map / sse_parse
• error: error_map
• metrics: usage extraction and finish_reason extraction