as4-411/docs/adr/002-resolution-scoring-determinism.md

ADR-002: Resolution Scoring and Determinism

Status

Accepted.

Context

Resolution must return a stable, ordered list of routing directives for the same inputs and store state.

Decision

Determinism

• Same normalized request + same directory state implies same ordered list of RouteDirectives.
• Tie-break when scores are equal: (1) explicit priority higher first, (2) lexical by endpoint id then participant id.

Scoring

• Factors: endpoint priority, endpoint status (active preferred over draining over inactive). No randomness; same inputs imply same scores and order.

Cache Key

• Derived from canonical request (sorted identifiers, serialized serviceContext and constraints, tenant).

Consequences

• Caching and retries are reproducible and safe.