Primitives.org.ai

Domain

URL-based namespaces that define context for AI and data

Domain

A Domain is the foundational namespace for all primitives. In this architecture, everything is URL-addressable - agents don't know file systems, they only know URLs.

The Namespace IS the Context

Here's the key insight: your domain namespace IS the $context - and this works on two levels simultaneously:

Semantic Context (JSON-LD)

In mdxld, every domain defines a JSON-LD @context that gives semantic meaning to your data:

$context: https://acme.do/
$type: Customer
name: Acme Corp

The namespace https://acme.do/ becomes the context that defines what "Customer", "name", and every other term means within your domain.

AI Context (LLM)

But here's the beautiful double-entendre: in AI systems, context is everything. The context window is what the LLM uses to understand, reason, and respond. When you define a domain:

  • You're giving the AI the semantic context to understand your business vocabulary
  • You're providing the cognitive context for the AI to reason about your domain
  • Every Noun, Verb, and Function you define enriches this context
// Your domain IS the context
const acme = Domain('acme.do')

// When an AI agent operates in this domain,
// it understands what "Customer", "Invoice", "approve" mean
// because the domain provides both semantic AND cognitive context

The namespace doesn't just organize your data - it teaches AI how to think about your business.

Overview

Every Noun, Verb, Thing, Function, and Agent lives within a domain. Domains provide identity, discovery, and access control.

import { Domain } from 'ai-functions'

// Define your domain
const domain = Domain('acme.do')

// Everything is URL-addressable
domain.nouns      // https://acme.do/nouns
domain.functions  // https://acme.do/functions
domain.agents     // https://acme.do/agents
domain.things     // https://acme.do/things

URL-First Architecture

Agents interact with the world through URLs:

// Agents discover capabilities via URLs
const customer = await fetch('https://acme.do/things/customer/cust_123')
const approve = await fetch('https://acme.do/verbs/approve')
const summarize = await fetch('https://acme.do/functions/summarize')

// Execute functions via HTTP
const result = await fetch('https://acme.do/functions/summarize', {
  method: 'POST',
  body: JSON.stringify({ text: document }),
})

Domain Configuration

import { Domain } from 'ai-functions'

const domain = Domain('mycompany.do', {
  // Display name
  name: 'My Company',

  // Domain description for discovery
  description: 'AI-powered business automation',

  // Authentication
  auth: {
    provider: 'oauth.do',
    methods: ['api-key', 'oauth2'],
  },

  // Access control
  access: {
    public: ['functions/summarize', 'nouns/*'],
    authenticated: ['things/*', 'actions/*'],
    admin: ['agents/*', 'config/*'],
  },
})

Resource URLs

Every resource has a canonical URL:

// Nouns (type definitions)
https://acme.do/nouns/Customer
https://acme.do/nouns/Invoice

// Things (instances)
https://acme.do/things/customer/cust_123
https://acme.do/things/invoice/inv_456

// Verbs (operations)
https://acme.do/verbs/approve
https://acme.do/verbs/ship

// Functions (AI capabilities)
https://acme.do/functions/summarize
https://acme.do/functions/translate

// Agents
https://acme.do/agents/sales-assistant
https://acme.do/agents/support-bot

// Workflows
https://acme.do/workflows/onboarding
https://acme.do/workflows/order-fulfillment

Discovery

Domains expose their capabilities for AI discovery:

// Well-known discovery endpoint
const capabilities = await fetch('https://acme.do/.well-known/ai')

// Returns structured capability manifest
{
  domain: 'acme.do',
  nouns: ['Customer', 'Invoice', 'Order'],
  verbs: ['create', 'approve', 'ship', 'refund'],
  functions: ['summarize', 'classify', 'extract'],
  agents: ['sales-assistant', 'support-bot'],
}

Cross-Domain References

Things can reference resources in other domains:

const order = Thing(Order, {
  customer: 'https://crm.do/things/customer/cust_123',
  payment: 'https://payments.do/things/charge/ch_789',
  shipping: 'https://logistics.do/things/shipment/ship_456',
})

Domain Federation

Domains can federate and trust each other:

const domain = Domain('acme.do', {
  federation: {
    trusted: ['partners.do', 'suppliers.do'],
    permissions: {
      'partners.do': ['read:things', 'execute:functions'],
      'suppliers.do': ['read:nouns'],
    },
  },
})

Context Propagation

When you execute a function or deploy an agent, the domain context flows through:

// The domain context enriches every operation
const result = await domain.functions.summarize({
  text: customerFeedback,
  // The AI knows "customer" means YOUR definition of customer
  // It knows your business vocabulary, your entities, your relationships
})

// Agents inherit domain context
const agent = domain.agents.supportBot
// This agent thinks in terms of YOUR Nouns, YOUR Verbs, YOUR business rules

This is why domains are so powerful: they're not just organizational units or URL prefixes. They're the shared understanding between your data, your code, and your AI.

See Also

  • Noun - Types within a domain
  • Thing - Instances within a domain
  • Function - Capabilities exposed by a domain
  • Agent - Actors operating within domains
  • mdxld - MDX with Linked Data and $context
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Primitives.org.ai

The fundamental abstractions for building AI-native software

Noun

Named entities and concepts in your domain

On this page

DomainThe Namespace IS the ContextSemantic Context (JSON-LD)AI Context (LLM)OverviewURL-First ArchitectureDomain ConfigurationResource URLsDiscoveryCross-Domain ReferencesDomain FederationContext PropagationSee Also