Schema classifier (AJV)

classify:schema loads one JSON Schema file per class, compiles each via the run-wide services.ajv instance, and tests every record against every compiled validator. Records with stable, well-defined shapes — where the property set reliably distinguishes one class from another — are a natural fit.

Each entry that returns true is a candidate. Highest-priority candidate writes its proposal to state.proposals['classify:schema'].

Configuration

Pass the entry list, the shared AJV instance, and the base directory for schema file resolution:

import { SchemaClassifierNode } from 'squashage/classifiers';

dispatcher.registerNode(new SchemaClassifierNode(
  [
    { className: 'Feat',   priority: 30, schemaPath: './schemas/Feat.schema.json' },
    { className: 'Spell',  priority: 30, schemaPath: './schemas/Spell.schema.json' },
    { className: 'Weapon', priority: 30, schemaPath: './schemas/Weapon.schema.json' },
  ],
  services.ajv,      // Ajv instance — shared across the run
  schemasBase,       // absolute path; schemaPath entries resolve against it
));

Schema files are read synchronously at construction — the constructor throws immediately if any file is missing or the JSON is invalid. The pipeline never starts with a broken schema list.

Field reference

Field	Type	Required	Notes
className	string	yes	Proposed class name when the schema validates.
priority	number	yes	Written onto the proposal. Highest-priority match wins when multiple schemas validate.
schemaPath	string	yes	Path to a JSON Schema file. Resolved against schemasBase.

Constructor arguments:

Argument	Type	Notes
entries	array	At least one entry required. Construction throws on an empty array.
ajv	Ajv	The run-wide AJV instance from services.ajv.
schemasBase	string	Absolute directory path. schemaPath values resolve against it.

Emitted proposal

When one or more schemas validate, the highest-priority match writes:

{
  "source":     "classify:schema",
  "className":  "Feat",
  "priority":   30,
  "confidence": 1,
  "reasons":    ["schema:Feat matched"]
}

All validating class names appear in reasons — the winner's name and every other match that fired:

{
  "reasons": ["schema:ContentEntry matched", "schema:Feat matched"]
}

When no schemas validate, the node outputs no-match.

Example — plugin registration

// plugins/aonprd/index.ts
import { SchemaClassifierNode } from 'squashage/classifiers';
import { fileURLToPath }         from 'node:url';
import { dirname, resolve }      from 'node:path';
import type { SquashageDagonizer } from 'squashage';
import type { SquashageServices }  from 'squashage/services';

const schemasBase = resolve(dirname(fileURLToPath(import.meta.url)), 'schemas');

export function register(
  dispatcher: SquashageDagonizer,
  services:   SquashageServices,
): void {
  dispatcher.registerNode(new SchemaClassifierNode(
    [
      { className: 'Feat',  priority: 30, schemaPath: './Feat.schema.json' },
      { className: 'Spell', priority: 30, schemaPath: './Spell.schema.json' },
    ],
    services.ajv,
    schemasBase,
  ));
}

See also

• Classifier cascade — full classifier set and priority ordering.
• SHACL shape classifier — RDF-level shape validation as a classification signal.
• Structural classifier — lightweight predicate-based alternative.