# Severity Fusion Prep — PREP-POLICY-ENGINE-40-001-SEVERITY-FUSION-DEP

Status: Draft (2025-11-20)
Owners: Policy Guild · Concelier Guild
Scope: Capture severity fusion requirements using violation events (38-201).

## Dependencies
- Violation event schema (38-201).
- Concelier severity sources + lattice rules; Policy weighting outputs (30-101).

## Draft fusion rules
- Inputs: violation events with status + severity + advisory/confidence.
- Rules: deterministic lattice; combine source severities with weights from 30-101; tie-break via Concelier source ranking; emit `severity_fused`, `reason_codes[]`, `sources[]` with weights.
- Determinism: sort sources lexicographically; fixed numeric precision (scale 3).

## Acceptance
- Schema draft at `docs/modules/policy/schemas/severity-fusion@draft.json` and sample at `docs/modules/policy/samples/severity-fusion@draft.json`.
- Document weight caps and rounding rules.

## Handoff
Prep artefact for PREP-POLICY-ENGINE-40-001-SEVERITY-FUSION-DEP. Finalize once violation events and Concelier severity ranking are frozen.