Installation

Prerequisites

• Node.js 20+ (Flint uses Web API primitives — fetch, ReadableStream, TextDecoder)
• A package manager: npm, pnpm, or yarn

Install

Choose one adapter. The Anthropic adapter is the default; the OpenAI-compatible adapter works with any OpenAI-format endpoint.

Anthropic

npm install flint @flint/adapter-anthropic

OpenAI-compatible

npm install flint @flint/adapter-openai-compat

Both

npm install flint @flint/adapter-anthropic @flint/adapter-openai-compat

Optional packages

# State machine workflows
npm install @flint/graph

TypeScript configuration

Flint requires "moduleResolution": "bundler" or "node16"/"nodenext" to resolve subpath exports correctly.

// tsconfig.json
{
  "compilerOptions": {
    "moduleResolution": "bundler",
    "target": "ES2022",
    "strict": true
  }
}

Set up your API key

export ANTHROPIC_API_KEY=sk-ant-...

Or use a .env file with your preferred dotenv loader (Flint does not load .env automatically).

Verify the install

import { call } from 'flint';
import { anthropicAdapter } from '@flint/adapter-anthropic';

const adapter = anthropicAdapter({ apiKey: process.env.ANTHROPIC_API_KEY! });

const res = await call({
  adapter,
  model: 'claude-opus-4-7',
  messages: [{ role: 'user', content: 'Say hello' }],
});

console.log(res.ok ? res.value.message.content : res.error.message);

NOTE

Flint is not yet published to npm. Install from the repository directly during v0: npm install github:DizzyMii/flint

Monorepo setup

In a monorepo, install at the workspace level:

pnpm add flint @flint/adapter-anthropic --filter my-app
# or
npm install flint @flint/adapter-anthropic -w packages/my-app

Runtime support

Runtime	Support
Node.js 20+	Full support
Bun 1.0+	Full support
Deno 1.40+	Full support (use npm: specifier)
Browser	Core works; adapters require CORS
Cloudflare Workers	Use fetch — no Node.js specifics needed
AWS Lambda	Node.js 20 runtime

Common installation errors

ERR_REQUIRE_ESM: Add "type": "module" to package.json.

Cannot find module 'flint/budget': Requires moduleResolution: "bundler" or "node16" in tsconfig.json.

Cannot find module '@standard-schema/spec': Run npm install again — peer dependency may not have been auto-installed.

See also

• Quick Start — first working example
• Setup — API key and TypeScript config