# ADR-0004: In-process worker topology for V1

- **Status:** accepted
- **Date:** 2026-06-25

## Context

The current system uses an in-process background worker. Architecture docs allow this in foundation stage and permit later hardening (optional external worker/queue).

## Decision

Retain in-process worker topology for V1, with improved lifecycle ownership:

1. Worker starts/stops via app lifespan.
2. Worker receives runtime-owned DB engine dependency explicitly.
3. Extension path to external worker remains behind existing service/adapter seams.

## Consequences

### Positive
- Keeps operational complexity low for personal-scale use.
- Preserves delivery focus on V1 completion.

### Tradeoffs
- Throughput/scaling limits remain compared to external queue-based topology.

## Alternatives Considered

1. **Immediate queue/external worker introduction**
   - Rejected: premature complexity for current scale.
2. **Ad hoc thread lifecycle management outside lifespan**
   - Rejected: weaker shutdown guarantees and poorer ownership clarity.