Glossary

This glossary defines how Northsun documentation uses important product and architecture terms. A definition can describe a live contract, an implemented but inactive substrate, or a design direction; the status is part of the meaning.

Identity and thesis

Northsun — The company and the platform documented here: the memory and enrichment layer for AI agents, under the northsun.ai name. The API, hosted MCP server, SDKs, and every page in this documentation set belong to Northsun. The brand name is not the API host — always call the host shown in the API reference.

Memory and enrichment layer for AI agents — The locked product identity. Northsun does not build agents. Builders connect voice, chat, coding, workflow, and custom agents through API, MCP, kits, or client surfaces that are available for the use case.

Governed context intelligence — The public differentiator and architecture direction: context should carry enough evidence, temporal meaning, policy, and auditability to be used responsibly. Individual governance mechanisms have different ship states; the phrase is not proof that every mechanism is active on every request.

Every agent proposes. Northsun governs. — The product thesis. Models generate actions and responses; the memory layer is being built to govern the context on which those actions stand.

Salience — The design goal of serving the right context, in the right amount, at the right time. Deterministic scoring and broader Beacon work are not part of the frozen public REST contract, and the caller read is not salience-ranked: recall_and_enrich returns stored caller memory newest call first, up to five. See Salience for the current boundary.

Stable caller-memory REST lifecycle

recall_and_enrich — POST /v1/recall_and_enrich. Accepts a phone number and returns caller-memory and enrichment branches defined in the API reference.

calls/end — POST /v1/calls/end. Accepts the completed interaction and returns 204 No Content after it is committed durably; a later recall_and_enrich for that caller normally returns it but may lag, so verify with a later controlled recall. See Hangup, and what happens next.

Caller profile — The profile returned by GET /v1/caller/{phone_number}. It represents stored caller context, not identity verification.

known — A recall-response boolean indicating whether Northsun found stored caller history. It is independent of whether enrichment fields are available.

trace_id — The identifier returned for a caller-memory request. Capture it with the request ID when diagnosing a voice-route failure.

Memory and governance constructs

Evidence refs — Provenance records that preserve where supported governed facts came from. Current scope and callable boundaries are documented in Evidence refs.

Bi-temporal validity — The separation between when something was true in the world and when the system learned or corrected it. Northsun currently applies this model to specific governed substrates, not every memory object. See Bi-temporal validity.

Locked facts — A governed-fact substrate with explicit assertion, evolution, correction, and as-of semantics. It is not part of the frozen three-endpoint public API. See Locked facts.

Context Space — The intended authority boundary for placing a memory version and granting principals access. The schema exists in the repository; public creation, binding, and composition controls are not available. See Context Spaces.

Policy bundle — A design for grouping server-side context rules. Do not infer that a policy bundle governs the frozen caller-memory routes merely because the concept is documented. See Policy bundles.

Validation gate — A server-owned checkpoint for evaluating proposed actions. Its Stage-1 evaluator exists in source; the complete gate is not public and remains outside the frozen public contract. See Validation gate.

Feedback loop — The evolving MCP pattern that connects served context to an observed outcome. The source contains context, observe, and feedback tools; authenticated production behavior remains a verification gate. See Feedback loop.

Problems the education system explains

Context rot — Context that remains available after its path, authority, validity, or meaning has changed.

Preamble tax — The token, latency, and attention cost of repeatedly loading broad context before useful work begins.

Agent amnesia — Loss of useful continuity between sessions, surfaces, or agent runtimes.

False green — A test or evaluation that appears healthy without measuring the behavior or outcome it claims to protect.

Enrichment

Enrichment — Contextual data returned alongside stored caller memory. Treat enrichment as evidence that may be partial or absent, never as identity proof. The public response groups available information under person, company, and phone.

Trestle and Twilio Lookup — The enrichment vendors Northsun may name publicly, and the only two. Their presence in the architecture does not guarantee that every response contains data or identify which vendor produced a particular visible field without a source receipt.

Tooling surfaces

MCP server — The hosted Model Context Protocol endpoint at https://mcp.northsun.ai/mcp. The current source advertises caller-memory, contact-workflow, and evolving context-loop tools. Inspect tools/list in the authenticated environment before relying on a tool in production. The local npm MCP-server package is not currently published.

Platform kit — Code intended to reduce integration work for a particular platform. A kit published on npm is stated with its version; it is still not automatically native, certified, or production-proven. The public guides therefore document the HTTP calls each kit makes and the mapping onto them.

Beacon — The design direction for proactive context delivery. Status: DESIGN. It is not part of the frozen public REST API and should not appear in a setup instruction as available behavior.

Ship-state labels

• Live — Observed in the deployed environment and usable under the stated conditions.
• Documented — Described by a current source-grounded contract; documentation alone does not establish deployment.
• Implemented, inactive — Code or schema exists but no active public path consumes it.
• Design — Specified architecture that is not a shipped customer capability.
• Planned — Intended work without a completed and verified contract.
• Requires verification — Evidence is missing or stale; do not repeat the claim as fact.

Pricing and performance language

Hobby $0; paid tiers Contact sales — The complete public pricing posture.

Designed for sub-300ms voice recall — The approved design language. It is not a measured percentile, guarantee, benchmark, or customer-outcome claim.

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