@orkestrel/qualifier

A typed eligibility engine over @orkestrel/reason: authored passes — quantitative derivations and logical rule gates — run in order against a subject (a plain data record) to produce findings (evidence-rich ruling outcomes), derivations (quantitative audit trails), and eligibility (global plus per-scope). The caller supplies the definition; Qualifier only evaluates what it is given. Qualification never mutates its inputs — every result is a fresh object. Environment-agnostic — no I/O, no browser or server assumptions. Part of the @orkestrel line.

Install

npm install @orkestrel/qualifier

Requirements

• Node.js >= 24
• ESM (import) and CommonJS (require) via the exports field

Usage

import { createQualifier, qualificationDefinition, rulingDefinition } from '@orkestrel/qualifier'
import { atom, logicalDefinition, rule } from '@orkestrel/reason'

const gates = logicalDefinition('gates', 'Eligibility gates', [
	rule('licensed', [atom('licensed', 'equals', false)], atom('blocked', 'equals', true)),
])

const definition = qualificationDefinition('standard', 'Standard eligibility', [gates], {
	rulings: [
		rulingDefinition('license', 'gates', 'licensed', 'restriction', {
			message: 'A license is required',
		}),
	],
})

const qualifier = createQualifier()
const result = qualifier.qualify({ id: 'risk-1', licensed: false }, definition)

result.eligibility // 'ineligible'
result.findings[0]?.message // 'A license is required'
result.derivations // [] — no quantitative pass ran

qualifier.destroy()

qualify accepts exactly one subject per call — there is no batch-of-subjects overload. Every qualify call fires once through qualifier.emitter (qualify).

Guide

For the full surface — Qualifier, QualificationResult, finding types, validators, factories, errors, and options — see guides/src/qualifier.md.

Package

Published as a single typed entry point per the exports field in package.json.

License

MIT © Orkestrel — see LICENSE.