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ADR 0011: Interoperability adapters as a single Protocol

  • Status: Accepted
  • Date: 2026-05-20
  • Authors: rmednitzer
  • Builds on: ADR 0001

Context

A backpack inference appliance has to speak the standards its peers expect: CoT/TAK for situational awareness, OGC SensorThings for environmental telemetry, MISB KLV for video metadata, NMEA 0183 for position, STANAG 4774/4778 for confidentiality labelling, MQTT for publish/subscribe. Each standard has its own encoder, parser, transport quirks, and conformance posture. Treating them as a flat list of ad-hoc modules invites duplication; treating them as plugins under a single Protocol keeps the seam testable.

Decision

Every interop adapter implements src/nous/interop/base.Adapter: encode(data) -> bytes and decode(payload) -> Mapping. Streaming adapters (CoT-over-TAK, MQTT) expose their own stream coroutine on top of the base. The v0.1 adapters are CoT, SensorThings, MISB KLV, NMEA 0183, STANAG 4774, and MQTT.

The conformance posture per standard lives under docs/conformance/. Each adapter has a model card-style page that states what is supported, what is omitted, and which version of the standard is targeted.

Consequences

Easier: a new adapter is one Python file, one conformance page, one test. The base Protocol is small enough to keep in working memory.

Harder: standards with stateful sessions (MQTT brokers, TAK servers) need lifecycle hooks that the Protocol does not enumerate; concrete adapters expose their own.

Revisit triggers

  • A standard requires a session model rich enough that the base Protocol is misleading.
  • A deployment needs to negotiate adapters dynamically (currently static; chosen at config time).