Relay#

Relay carries a model invocation across a runtime boundary without deciding which model should be used or what the response means.

Language#

Model Runtime: An implementation of Relay's invocation contract. It may use a direct SDK, local engine, hosted service, or agent framework.

Invocation: One request/result exchange with normalized provider, model, usage, latency, stop reason, and failure identity.

Output Token Limit Fidelity: A runtime capability declaring whether maxOutputTokens is natively enforced, approximated, or unavailable. A request does not imply enforcement when a profile declares otherwise.

Runtime Target: Constructor-only provider configuration supplied by a host, often after Datum resolution. Credentials are never invocation data.

Harness Profile: A thin mapping between a supported non-interactive process protocol and Relay's invocation contract. It declares only capabilities the harness can actually provide; the shared process transport owns execution, abort, output bounds, and sanitized failure behavior.

Domain Adapter: A product-owned translation between its semantic operation and Relay invocation. Traverse extraction is one example.

Boundaries#

• Bearing owns model capability evidence.
• Datum owns provider/model/secret-reference and role resolution.
• Relay owns invocation portability.
• Domain products own prompts, schemas, and interpretation.
• Flow owns process semantics; Flow Agents owns agent workflow enforcement.