Core concepts · 28 / 42

Overview

Northsun's primitives have different ship states: caller memory is the frozen public REST surface, while evidence, facts, policy, and validation are not.

Northsun is the memory and enrichment layer for AI agents. Its public caller-memory lifecycle is available through three REST endpoints, while a broader governed-context model is being built from evidence, temporal facts, policy, validation, and feedback primitives. The primitives do not all share the same ship state.

State map

Concept	Purpose	Current documentation state
Caller memory	Recall prior interactions before a call and submit the completed interaction afterward.	Frozen public REST surface.
Enrichment	Can include nullable person, company, and phone context from Trestle and Twilio Lookup.	Public response shape; optional evidence, not identity proof.
Hosted MCP	Let compatible agent clients discover Northsun tools.	Endpoint and source-defined tools exist; authenticated production lifecycle remains a release proof gate.
`evidence_refs`	Store tenant-scoped source pointers, hashes, lineage, priority, and temporal metadata.	Repository substrate; no direct public evidence API.
`locked_facts`	Store evidence-backed, versioned entity facts with valid and transaction time.	Repository substrate; no direct public facts API.
Policy bundles	Describe versioned rules for evaluating a proposed action.	Governed design; not publicly callable.
Validation gate	Evaluate an action against deterministic and qualitative rules.	Stage 1 is built in source; the complete gate is not public and remains outside the frozen public contract.
Feedback loop	Link served context to an observed outcome or correction.	Evolving MCP/internal direction; exact deployed contract must be observed.
Beacon/salience (design stage)	Decide whether and when to surface proactive context.	Design state; no proactive public runtime.

“Substrate” means code or migrations exist in the repository. It does not prove production deployment, universal use by every response, or customer-visible behavior.

The public caller-memory loop

recall_and_enrich
  -> application selects safe context
  -> agent interaction
  -> calls/end acknowledgement
  -> a later controlled read confirms the write

The application still owns the agent, platform event mapping, context selection, fallback behavior, consent, and end-to-end verification. See Quickstart and Voice integration patterns.

The governed-context substrate

The repository model separates source evidence from addressed facts:

source event
  -> evidence_refs (source, hash, lineage, time)
  -> locked_facts (tenant, entity, key, value, valid time, transaction time)
  -> future policy/validation serving path

evidence_refs are namespace-agnostic. locked_facts use entity_id and fact_key. Bi-temporal scope is limited to those two governed tables; memory_objects are not bi-temporal under the locked D3 decision.

The direction: governed context intelligence

The design goal is not to make every stored item permanent or to inject more text into every prompt. It is to make serving decisions inspectable: which entity, which source, what valid time, which authority, how much context, and what outcome followed.

That is the meaning of Every agent proposes. Northsun governs. It is the public differentiator and architecture thesis. It is not a statement that every current agent action already passes through a production validation gate.

Continue with Evidence references, Locked facts, Bi-temporal validity, and Salience and Beacon (design stage). Each page preserves its own public/substrate/design boundary.