# Evidence contributes to semantic workflow stages

The Evidence Module is a contributor to the existing semantic stages, not a visible
workflow stage. `clarification`, `rewriting`, `schema_linking`, `cte` and `final_sql`
query it with their corresponding purpose; `memory` remains owned by the Memory Module
and `synthesis` performs no Evidence search. Each mapped stage searches independently
and the workflow records only a minimal receipt containing stage, purpose, vector
generation and returned Evidence IDs.

A successful search may return no matches and does not block the stage. Technical
unavailability is a distinct typed outcome that blocks the calling stage until retry,
without stale-generation or purpose fallback. This favors an explicit temporary stop
over silently treating a broken Evidence dependency as absence of domain knowledge.