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Fetch API

Fetch · Signal Layer Surface · v1.0

The addressable surface of the Signal Layer.

Fetch is the addressable surface of the Signal Layer — a small, composable interface (signals, webhooks, replay, cohorts, confidence) through which every consumer interprets the same biological intelligence in its own context.

§ 02Why an Interface

Intelligence becomes infrastructure when it is reachable.

Companion synthesises continuous longitudinal signal. Fetch is the surface that lets that signal cross system boundaries — into vet workflows, insurer pricing, shelter operations, IoT loops, research cohorts — without losing meaning.

Companion · Signal Engine
Vet EMRInsurerIoTShelterPet-parentResearch
§ 03Signal Objects
SignalThe atomic unit. A synthesised behavioural inference.
DeviationA measured departure from the subject's baseline.
ConfidenceProbabilistic weight on every inference.
CohortPeer-group context against which signals are interpreted.
WindowIntervention timeframe surfaced alongside risk.
ReplayTime-indexed history of how a signal emerged.
§ 04Endpoints
  • GET/v1/subjects/{id}
  • GET/v1/subjects/{id}/signals
  • GET/v1/subjects/{id}/replay
  • GET/v1/cohorts/{id}
  • GET/v1/cohorts/{id}/risk
  • POST/v1/webhooks
  • GET/v1/events
§ 05Webhook Events

Push, not poll.

Webhooks carry signal emergence, threshold crossings and confidence updates as they happen. Consumers subscribe to the events that matter to their context and ignore the rest.

  • signal.emerged
  • signal.persistence.crossed
  • risk.elevated
  • risk.de-escalated
  • cohort.drift
  • subject.intake
POST /partner/webhook
X-Fetch-Signature: sha256=••••

{
  "event": "signal.emerged",
  "subject": "PET-00472",
  "signal": {
    "kind": "hydration_drift",
    "deviation": 0.49,
    "confidence": 0.87,
    "window": "14d"
  },
  "as_of": "2026-05-25T00:00:00Z"
}
§ 06Replay

Scrub the longitudinal record.

Every signal is time-indexed. Replay lets consumers reconstruct exactly what the system understood about a subject at any prior moment — the forensic substrate behind every decision.

−48dnow
§ 07Confidence Model

No inference without confidence.

Every response carries a confidence value. Consumers can threshold, defer, or escalate accordingly. Confidence is exposed in every signal object, every cohort response, every webhook payload.

signal.hydration_drift
0.87
signal.weight_velocity
0.74
signal.activity_baseline
0.62
signal.sleep_phase_shift
0.41
§ 08Integration Patterns
Veterinary EMREmbed signal cards beside the patient record.
Insurer pricingCohort risk feeds nightly into underwriting models.
IoT closed-loopSubscribe to signal.emerged · adjust device cadence.
Shelter opsAdoption readiness surfaced inside intake consumer surfaces.
Pet-parent appsCalm, confidence-aware context for caregivers.
§ 09Auth & Operational

Scoped keys. Versioned surface. Sandbox first.

Access is granted per-consumer with scoped API keys, environment separation, request signing on webhooks, and a versioned endpoint surface. Breaking changes ship behind new versions, never silently.

Environmentssandbox · staging · production
AuthBearer key, per-consumer scope
WebhooksHMAC-SHA256 signature
VersioningURL-prefixed (/v1/, /v2/)
Rate limitsPer-key, surfaced in response headers

The public expression of the ontology.

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