Companion Fetch
Technical Overview
Architectural Systems Spec
Fetch API · Architectural Systems Specification

The longitudinal intelligence layer.

A technical overview of the infrastructure that converts fragmented companion-animal observation into persistent, replayable, interpretive continuity across the ecosystem.

The interoperability surface of a longitudinal inference infrastructure for the pet ecosystem.

01 · Technical Thesis

Companion Health is a longitudinal inference infrastructure layer for the pet ecosystem.

It synthesises fragmented behavioural, clinical, nutritional, insurance, and research observations into persistent health intelligence over time.

Companion does not replace source systems. It creates interpretive continuity across them.

Identity

Companion Health is biological intelligence infrastructure for the global pet ecosystem. Fetch API is the addressable surface of that infrastructure — the programmable interface through which participants observe, retrieve, and interpret the persistent intelligence the platform synthesises.

Scope of this document

The architecture underneath Fetch API: the data model, the inference engine, the temporal reconstruction system, the interpretation layer that translates intelligence into consumer-specific outputs, and the integration patterns that connect ecosystem participants to the platform.

02 · Architecture Overview

A nine-layer stack with one cross-cutting orchestration layer.

Each layer carries a single responsibility. Layer boundaries are the contract — what each accepts, what it produces, and what remains its own concern. The Signal Engine is the structural and conceptual centre.

Layer
Responsibility · accepts → produces
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Numbered stack

Nine layers form a vertical compositional hierarchy. Telemetry enters at Layer 1, is normalised through Layer 2, validated at Layer 3, and synthesised into signals at Layer 4 — the Signal Engine.

Interpretation Layer

A cross-cutting orchestration layer operates laterally between Layer 8 and Layer 9, composing primitives into consumer-specific Briefs without inventing parallel concepts.

Fig. 02.01 · The Fetch Topology — one subject, many relationships, one API
Companion Health topology — telemetry inputs flow through the Signal Layer and Interpretation Layer, exposed as consumer Briefs via Fetch API
Telemetry inputs are synthesised into signals, orchestrated by the Interpretation Layer, and delivered as consumer-specific Briefs — all through a single contract surface, the Fetch API.
03 · Engineering Principles

Five principles govern every design decision.

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04 · The Signal Engine

Synthesis is not detection. It is reconstruction.

The engine does not watch for thresholds. It establishes what is normal for a single subject over time, measures sustained deviation against a cohort-adjusted baseline, and reconstructs how a signal emerged. Six operations compose it.

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05 · Data Model & Ontology

Seven primitives compose every object.

The ontology is the vocabulary of the system — it governs the data model, the API surface, the storage schema, and the consumer interface. Outside it, no terminology is introduced.

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Signal — canonical schema

The Signal object is the system's unit of currency. Its schema is intentionally narrow — every field load-bearing, every claim disclosed.

Signal object · primitive
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06 · Fetch API Surface

The API exposes the ontology. It does not invent parallel concepts.

Two endpoint families, one worldview: primitive endpoints expose the seven objects directly; Brief endpoints expose consumer-specific compositions. New signal classes are added as values, not new endpoints.

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Canonical Signal response

A Signal retrieval returns the primitive in its canonical shape — narrow, composable, fully disclosed. No diagnosis, no recommendation, no consumer framing.

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07 · Replay Engine

Replay turns a predictive system into an evidentiary one.

A signal that cannot be reconstructed cannot be defended. Replay reconstructs the day-by-day emergence of every signal — forensic, immutable, reviewable. Three properties compose it.

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08 · Interpretation Layer

The same signal becomes different intelligence in different consumer hands.

One underlying signal composes into many Briefs — each weighted for the consumer's interpretive frame. A single intelligence layer serves an unbounded number of consumers; Companion never competes with the products that consume it.

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09 · Intelligence Services

Nine services turn observation into intelligence.

This is where the intelligence lives. Not a model, not a chatbot — a sequence of nine deterministic services between a raw observation and a delivered interpretation, each with a single responsibility. They populate the nine-layer stack and feed the Signal Engine at its centre.

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10 · The Canonical Intelligence Exchange

Fetch becomes more valuable as the ecosystem grows.

Every observation contributed sharpens the cohorts every other subject is interpreted against. The architecture is not a pipeline that ends at delivery — it is a loop that compounds. This is the structural basis of the Companion Intelligence Network.

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The compounding property

Network learning closes the loop: each consumer interaction and each new contributor refines the cohorts, which sharpens every future signal and interpretation. Fetch is the exchange through which this accrues — the Canonical Intelligence Exchange — and the reason participation compounds in value rather than merely adding volume.

Notices
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