@semiont/core

Core types and domain logic for the Semiont semantic knowledge platform. This package is the source of truth for OpenAPI types and provides backend utilities for event sourcing, URIs, DID generation, and the EventBus.

Architecture Note: This package generates TypeScript types from the OpenAPI specification. @semiont/api-client re-exports these types and provides HTTP client functionality.

Who Should Use This

• ✅ Backend (apps/backend) - Server implementation, imports types from core
• ✅ Packages - Other monorepo packages that need OpenAPI types or EventBus
• ✅ Internal Utilities - Type generation, validation, domain logic
• ✅ Frontend / Browser - Types and pure utilities (main barrel is browser-safe)

Who Should Use @semiont/core/node Instead

Node.js-specific exports live in the /node subpath:

import { SemiontProject, loadEnvironmentConfig } from '@semiont/core/node';

• SemiontProject — represents a project on the filesystem; resolves XDG directories, reads/writes files. Not usable in a browser.
• loadEnvironmentConfig — loads ~/.semiontconfig + .semiont/config using fs/os/path. Not usable in a browser.

Rule: If your code runs in a browser or edge runtime, use @semiont/core. If it runs in Node.js and needs filesystem access, use @semiont/core/node.

Who Should Use @semiont/api-client Instead

• External Applications - For HTTP client + utilities
• Frontend (apps/frontend, packages/react-ui) - For API communication and W3C utilities
• Demo Scripts - For higher-level API access
• MCP Servers - For client-side annotation utilities

Rule of thumb: If you need to make HTTP requests or work with W3C selectors, use @semiont/api-client. If you only need types and domain logic, use @semiont/core.

Installation

Install the latest stable release from npm:

npm install @semiont/core

Or install the latest development build:

npm install @semiont/core@dev

What's Included

OpenAPI Types (Generated)

TypeScript types generated from the OpenAPI specification - the source of truth for all API schemas:

import type { components, paths, operations } from '@semiont/core';

type Annotation = components['schemas']['Annotation'];
type Resource = components['schemas']['Resource'];
type CreateResourceRequest = components['schemas']['CreateResourceRequest'];

These types are generated during the build process:

npm run generate:openapi  # Bundles spec → generates types.ts

Branded Types

Compile-time type safety for URIs, tokens, and identifiers:

import { resourceUri, annotationUri, accessToken, entityType } from '@semiont/core';

const rUri = resourceUri('http://localhost:4000/resources/doc-123');
const token = accessToken('eyJhbGc...');
const eType = entityType('Person');

Event Sourcing Types

Event types for the event-sourced architecture:

import type {
  ResourceEvent,
  ResourceCreatedEvent,
  ResourceArchivedEvent,
  DocumentUnarchivedEvent,
  AnnotationAddedEvent,
  AnnotationRemovedEvent,
  AnnotationBodyUpdatedEvent,
  EntityTagAddedEvent,
  EntityTagRemovedEvent,
  StoredEvent,
  EventMetadata,
  DocumentAnnotations,
  BodyOperation,
} from '@semiont/core';

DID Utilities

Generate W3C Decentralized Identifiers for annotations:

import { userToDid, userToAgent, didToAgent } from '@semiont/core';

// Convert user to DID:WEB
const did = userToDid(user);
// => 'did:web:localhost%3A4000:users:user-id'

// Convert user to W3C Agent
const agent = userToAgent(user);
// => { id: 'did:web:...', type: 'Person', name: 'User Name' }

Cryptographic Utilities

Content-addressing and checksums:

import {
  generateId,
  generateToken,
  generateUuid,
  calculateChecksum,
  verifyChecksum,
} from '@semiont/core';

// Generate unique IDs
const id = generateId();
const token = generateToken();
const uuid = generateUuid();

// Content checksums for verification
const checksum = calculateChecksum(content);
const isValid = verifyChecksum(content, checksum);

Type Guards

Runtime type checking:

import {
  isString,
  isNumber,
  isBoolean,
  isObject,
  isArray,
  isNonEmptyArray,
  isDefined,
} from '@semiont/core';

if (isNonEmptyArray(value)) {
  // TypeScript knows value is T[] with length > 0
}

Error Classes

Backend error types:

import {
  SemiontError,
  APIError,
  NotFoundError,
  ConflictError,
  ValidationError,
  UnauthorizedError,
} from '@semiont/core';

throw new NotFoundError('Document not found');
throw new ValidationError('Invalid annotation format');

HTTP Client Utilities

Backend HTTP utilities (internal use):

import { fetchAPI, createFetchAPI } from '@semiont/core';

const response = await fetchAPI(url, { method: 'POST', body: data });

Backend-Specific Annotation Utilities

Utilities that work with internal backend types:

import { bodyItemsMatch, findBodyItem } from '@semiont/core';

// Find specific body item in annotation
const item = findBodyItem(annotation.body, (item) => item.purpose === 'tagging');

// Check if two body items match
if (bodyItemsMatch(item1, item2)) {
  // ...
}

Backend Internal Types

Types not in the OpenAPI spec:

import type {
  UpdateDocumentInput,
  ResourceFilter,
  CreateAnnotationInternal,
  AnnotationCategory,
  GoogleAuthRequest,
  GraphConnection,
  GraphPath,
  EntityTypeStats,
} from '@semiont/core';

Constants

Backend-specific constants:

import { CREATION_METHODS } from '@semiont/core';

CREATION_METHODS.API          // 'api'
CREATION_METHODS.PASTE        // 'paste'
CREATION_METHODS.FILE_UPLOAD  // 'file-upload'
CREATION_METHODS.REFERENCE    // 'reference'
CREATION_METHODS.IMPORT       // 'import'

What's NOT Included

The following utilities have been moved to @semiont/api-client (as of 2025-10-24):

❌ Selector Utilities

Use @semiont/api-client instead:

// OLD (removed from @semiont/core):
import { getExactText, getTextPositionSelector } from '@semiont/core';

// NEW (use @semiont/api-client):
import { getExactText, getTextPositionSelector } from '@semiont/api-client';

❌ Locale Utilities

Use @semiont/api-client instead:

// OLD (removed from @semiont/core):
import { LOCALES, formatLocaleDisplay, getLocaleInfo } from '@semiont/core';

// NEW (use @semiont/api-client):
import { LOCALES, formatLocaleDisplay, getLocaleInfo } from '@semiont/api-client';

❌ Annotation Utilities (Public API)

Use @semiont/api-client instead:

// OLD (removed from @semiont/core):
import { compareAnnotationIds, getEntityTypes, getBodySource } from '@semiont/core';

// NEW (use @semiont/api-client):
import { compareAnnotationIds, getEntityTypes, getBodySource } from '@semiont/api-client';

Architecture: Spec-First

Semiont follows a spec-first architecture:

1. OpenAPI Specification (specs/src/) is the source of truth
2. @semiont/core generates types from OpenAPI and provides utilities
3. @semiont/api-client re-exports types from core and provides HTTP client

Principle:

• OpenAPI types & domain utilities → @semiont/core (source of truth)
• HTTP client & convenience re-exports → @semiont/api-client
• Backend internal implementation → imports from @semiont/core

Type Yield Flow: OpenAPI spec → @semiont/core/src/types.ts (via openapi-typescript) → re-exported by @semiont/api-client for convenience. This ensures no circular dependencies and clear build order.

Development

# Build the package
npm run build

# Type check
npm run typecheck

# Clean build artifacts
npm run clean

License

Apache-2.0

Related Packages

• @semiont/api-client - Primary TypeScript SDK (use this for most cases)
• @semiont/backend - Backend API server
• @semiont/frontend - Web application

Learn More

• W3C Web Annotation Model - Annotation standard
• DID:WEB Specification - Decentralized identifiers
• W3C Selectors - Selector implementation details