MSP-1 Namespace

This document describes the namespace for the Mark Semantic Protocol (MSP-1). The namespace URI is:

https://msp-1.com/ns#

MSP-1.0.0 — Draft

1. Overview

The MSP-1 namespace defines properties and classes used to represent page-level metadata about verification level, sourcing, AI involvement, and review history for web content.

In JSON-LD, the namespace is typically bound to the prefix "msp", and terms are used as msp:termName. For example, msp:verificationLevel expands to https://msp-1.com/ns#verificationLevel.

For the full MSP-1 specification, see: MSP-1 Specification (Draft 1.0.0).

2. Core Properties

Term (Fragment) Expanded IRI Type Description
mspVersion https://msp-1.com/ns#mspVersion Property (string) MSP protocol version string, e.g. "MSP-1.0.0".
pageId https://msp-1.com/ns#pageId Property (string) Stable identifier for the page within the site.
siteId https://msp-1.com/ns#siteId Property (string) Identifier for the implementing site, typically the primary domain.
verificationLevel https://msp-1.com/ns#verificationLevel Property (string enum) Verification status for the page. Allowed values in MSP-1 are "core", "verified", and "authoritative".
contentType https://msp-1.com/ns#contentType Property (string) Logical type of the content, e.g. "article", "guide", "reference".
topic https://msp-1.com/ns#topic Property (string) Short topic key or category describing the primary subject of the page.
lastUpdated https://msp-1.com/ns#lastUpdated Property (dateTime) Date and time when the content was last updated.
lastReviewed https://msp-1.com/ns#lastReviewed Property (dateTime) Date and time when a human last reviewed the content.
language https://msp-1.com/ns#language Property (string) Language code for the content, e.g. "en-US".
Source-related terms
Term Expanded IRI Type Description
sources https://msp-1.com/ns#sources Property (array of Source) List of source objects that support key factual claims on the page.
Source https://msp-1.com/ns#Source Class Represents a single primary, secondary, or tertiary source used by the page.
type https://msp-1.com/ns#sourceType Property (string enum) Classification of the source as "primary", "secondary", or "tertiary".
title https://msp-1.com/ns#sourceTitle Property (string) Title of the source work.
url https://msp-1.com/ns#sourceUrl Property (URI) URL where the source can be accessed.
publisher https://msp-1.com/ns#sourcePublisher Property (string) Publisher or organization responsible for the source.
publishedDate https://msp-1.com/ns#sourcePublishedDate Property (date) Date when the source was originally published, if known.
accessedDate https://msp-1.com/ns#sourceAccessedDate Property (date) Date when the site author last accessed the source.
notes https://msp-1.com/ns#sourceNotes Property (string) Optional notes about how or why the source was used.
AI-related terms
Term Expanded IRI Type Description
ai https://msp-1.com/ns#ai Property (object) Object describing how AI systems were involved in creating or editing the content.
used https://msp-1.com/ns#aiUsed Property (boolean) Indicates whether AI was used at any stage in the content lifecycle.
role https://msp-1.com/ns#aiRole Property (array of string) Describes AI roles, such as "drafting", "editing", "fact-checking", "image-generation", or "other".
models https://msp-1.com/ns#aiModels Property (array of string) Names or identifiers of AI models used (e.g. "GPT-5.1 Thinking").
humanReviewed https://msp-1.com/ns#aiHumanReviewed Property (boolean) Indicates whether the AI-assisted content was reviewed by a human.
Update policy terms
Term Expanded IRI Type Description
updatePolicy https://msp-1.com/ns#updatePolicy Property (object) Optional object describing how often the page is reviewed and what events trigger updates.
frequency https://msp-1.com/ns#updateFrequency Property (string) Describes the intended review cadence (e.g. "annually").
triggeredBy https://msp-1.com/ns#updateTriggeredBy Property (string) Describes events that should trigger an off-cycle review (e.g. “major camera market changes”).

3. JSON-LD Context Example

Implementers may reference this namespace in a JSON-LD context as follows: 

{
  "@context": {
    "schema": "https://schema.org/",
    "msp": "https://msp-1.com/ns#"
  }
}

Terms such as msp:verificationLevel or msp:lastReviewed then resolve against this namespace document.