transcription/docs/adr/ADR-0004-in-process-worker-topology.md

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.