# ADR 0003 — Existing Prometheus-compatible source remains v1 metrics history

**Status:** Accepted baseline

## Decision

Use the existing Prometheus-compatible endpoint for instant/range queries and retention in v1. Do not introduce VictoriaMetrics or another time-series database until measurements show a concrete retention, performance or reliability requirement.

## Rationale

Avoid duplicate infrastructure and migration risk. Pulse differentiates through semantic queries, UX, inventory, alerts and incidents.

## Consequences

- Query planner and limits protect the source.
- Pulse stores no full metric history in PostgreSQL.
- Long-term storage remains a future measured decision.