# HigherOrderCO/Kind

A modern proof language

Repository: https://github.com/HigherOrderCO/Kind
Canonical: https://ross.abutalabs.com/products/higherorderco-kind
Homepage: https://higherorderco.com
Language: Haskell
License: MIT
License Family: permissive
Topics: formality, lambda-calculus, type-theory, proof-language, functional-programming, dependent-types, moonad, proof-languages, theorem-prover
Last push: 2025-01-22T16:54:12+00:00

## Health v2 (maintenance only)
Score: 24/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 2, release rhythm 8, longevity 100
- inputs: {"age_days": 2973, "days_push": 588, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3766, forks 151 (observed 2026-08-28T04:08:18.067058+00:00)

## What it is
Kind is a minimal proof language and proof checker based on dependent type theory and lambda calculus, rewritten from JavaScript to Haskell. It is invoked via the 'kind' command-line tool to type-check and run proof terms, and is part of the Higher Order Company ecosystem alongside HVM and Bend.

## Use cases
- verify mathematical proofs with a lightweight proof assistant
- write and type-check programs with dependent types
- experiment with lambda calculus and type theory terms
- learn proof techniques in a minimal proof language
- formally verify functional programs
- prove theorems without heavyweight proof assistant tooling

## When to choose
- you want a minimal, easy-to-grasp proof checker instead of heavyweight assistants like Coq, Lean, or Agda
- you want to learn dependent type theory and lambda calculus through hands-on proof writing
- you are working within or exploring the HVM/Bend formal ecosystem
- you prefer a simple command-line workflow for checking and running proof terms

## When to avoid
- you need a mature proof assistant with large standard libraries, tactics, and IDE integration
- you need a general-purpose programming language with a rich ecosystem for production software
- you require extensive documentation and long-term stability guarantees
- you need interactive theorem proving with automation beyond simple type checking

## Facets
- artifact type: cli-tool
- maturity: active
- function: programming-language, type-system, interpreter, cli, math
- domain: programming-languages, mathematics, compilers, developer-tools
- platform: cli, cross-platform, windows
- tags: proof-language, proof-checker, dependent-types, lambda-calculus, type-theory, theorem-prover, formal-verification, functional-programming, haskell, formality, hvm-ecosystem, command-line, linux, macos

## Member repositories
- HigherOrderCO/Kind (main) score 24

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:18.067058+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:28:35.931909+00:00, confidence not recorded.
  - readme: https://github.com/HigherOrderCO/Kind (fetched 2026-08-28T04:08:18.067058+00:00, sha 8b9f8406b055)
  - homepage: https://higherorderco.com (fetched 2026-08-29T09:22:39.861626+00:00, sha 79cef861f61c)
- Data as of 2026-08-30T08:39:29.467469+00:00.