QA provider lanes are registered in index.ts and implemented in one folder per provider. Shared provider contracts and mock-provider helpers live in shared/. Mock lanes should use shared/mock-provider-definition.ts unless they need a custom shape.

Each provider definition owns:

its accepted providerMode
default primary, alternate, and image-generation model refs
gateway models.providers config, when the lane needs config injection
model runtime params such as SSE transport, fast mode, or thinking defaults
optional local server startup for mock lanes
optional placeholder auth profile providers for mock lanes
whether the lane uses real provider plugins and live environment aliases

Shared suite code should import only providers/index.ts and ask the selected provider for behavior. Do not add provider-name branches to suite, gateway, manual-lane, or live-transport runtime code unless the registry contract is missing a needed capability.