Capable

Capable is a TypeScript framework for defining a capability once and exposing it through the surfaces your application needs: typed calls, HTTP, CLI, MCP, AI tools, and more.

Schemas may come from any library that implements both Standard Schema and Standard JSON Schema. This example uses Zod as a provider:

pnpm add capable-kit zod

import { capability, defineApp } from "capable-kit";
import { z } from "zod";

const greet = capability({
  id: "greet",
  input: z.object({ name: z.string() }),
  handler: ({ input }) => ({ message: `Hello, ${input.name}` }),
});

export default defineApp({
  name: "Greeting",
  capabilities: { greet },
});

TypeScript infers the handler's output type. An output schema is optional and adds runtime output validation plus a portable schema for OpenAPI and tool surfaces.

Capable is early alpha software. APIs may change without compatibility layers.

The package provides the cap CLI command. capable remains an alias:

cap dev

Deploy

Capable detects supported build environments such as Vercel and emits their native deployment output:

vercel

To create Vercel's Build Output API locally instead:

cap build --preset vercel
vercel deploy --prebuilt

For a deployment protected by Vercel Authentication, link the local project. Capable reuses the Vercel CLI login to resolve that project's Protection Bypass for Automation:

vercel link
cap cli --app https://your-app.vercel.app hello

An explicit environment variable remains available for CI or unlinked projects:

export VERCEL_AUTOMATION_BYPASS_SECRET="..."
cap cli --app https://your-app.vercel.app hello

Documentation

Documentation matching the installed version ships at:

node_modules/capable-kit/docs/

Coding agents should start with node_modules/capable-kit/docs/README.md, then read the relevant guide before writing Capable code. The package also includes its original TypeScript source under src/ when a guide does not cover a lower-level API detail.

Package contents

The published package includes compiled ESM in dist/, declaration files, the original TypeScript authoring source in src/, and the complete documentation in docs/. User-facing guides are under docs/site/; framework design notes and invariants are under docs/internal/.