npm package: @node-llm/core
Description: A provider-agnostic LLM core for Node.js, inspired by ruby-llm.
Author: NodeLLM contributors
Latest version: 1.15.2

# @node-llm/core

<p align="left">
  <a href="https://nodellm.dev/">
    <img src="https://nodellm.dev/assets/images/logo.png" alt="NodeLLM logo" width="300" />
  </a>
</p>

[![npm version](https://img.shields.io/npm/v/@node-llm/core.svg)](https://www.npmjs.com/package/@node-llm/core)
[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
[![TypeScript](https://img.shields.io/badge/TypeScript-Ready-blue.svg)](https://www.typescriptlang.org/)

**The production-grade LLM engine for Node.js. Provider-agnostic by design.**

`@node-llm/core` provides a single, unified API for interacting with over 540+ models across all major providers. It is built for developers who need stable infrastructure, standard streaming, and automated tool execution without vendor lock-in.

---

## 🚀 Key Features

- **Unified API**: One interface for OpenAI, Anthropic, Gemini, DeepSeek, OpenRouter, and Ollama.
- **Automated Tool Loops**: Recursive tool execution handled automatically—no manual loops required.
- **Streaming + Tools**: Seamlessly execute tools and continue the stream with the final response.
- **Structured Output**: Native Zod support for rigorous schema validation (`.withSchema()`).
- **Multimodal engine**: Built-in handling for Vision, Audio (Whisper), and Video (Gemini).
- **Security-First**: Integrated circuit breakers for timeouts, max tokens, and infinite tool loops.

---

## 📋 Supported Providers

| Provider                                                                                                                             | Supported Features                                                                               |
| :----------------------------------------------------------------------------------------------------------------------------------- | :----------------------------------------------------------------------------------------------- |
| <img src="https://registry.npmmirror.com/@lobehub/icons-static-svg/latest/files/icons/openai.svg" height="18"> **OpenAI**            | Chat, Streaming, Tools, Vision, Audio, Images, Transcription, **Reasoning**                      |
| <img src="https://registry.npmmirror.com/@lobehub/icons-static-svg/latest/files/icons/anthropic-text.svg" height="12"> **Anthropic** | Chat, Streaming, Tools, Vision, PDF, Structured Output, **Extended Thinking (Claude 3.7)**       |
| <img src="https://registry.npmmirror.com/@lobehub/icons-static-svg/latest/files/icons/gemini-color.svg" height="18"> **Gemini**      | Chat, Streaming, Tools, Vision, Audio, Video, Embeddings                                         |
| <img src="https://registry.npmmirror.com/@lobehub/icons-static-svg/latest/files/icons/deepseek-color.svg" height="18"> **DeepSeek**  | Chat (V3), **Extended Thinking (R1)**, Streaming, Tools                                          |
| <img src="https://registry.npmmirror.com/@lobehub/icons-static-svg/latest/files/icons/bedrock-color.svg" height="18"> **Bedrock**    | Chat, Streaming, Tools, Image Gen (Titan/SD), Embeddings, **Prompt Caching**                     |
| <img src="https://registry.npmmirror.com/@lobehub/icons-static-svg/latest/files/icons/openrouter.svg" height="18"> **OpenRouter**    | 540+ models, Chat, Streaming, Tools, Vision, Embeddings, **Reasoning**                           |
| <img src="https://registry.npmmirror.com/@lobehub/icons-static-svg/latest/files/icons/ollama.svg" height="18"> **Ollama**            | **Local Inference**, Chat, Streaming, Tools, Vision, Embeddings                                  |
| <img src="https://registry.npmmirror.com/@lobehub/icons-static-svg/latest/files/icons/mistral-color.svg" height="18"> **Mistral**    | Chat, Streaming, Tools, Vision, Embeddings, Transcription, Moderation, **Reasoning (Magistral)** |

---

## ⚡ Quick Start

### Installation

```bash
npm install @node-llm/core
```

### Basic Chat & Streaming

NodeLLM automatically reads your API keys from environment variables (e.g., `OPENAI_API_KEY`).

```ts
import { createLLM } from "@node-llm/core";

const llm = createLLM({ provider: "openai" });

// 1. Standard Request
const res = await llm.chat("gpt-4o").ask("What is the speed of light?");
console.log(res.content);

// 2. Real-time Streaming
for await (const chunk of llm.chat().stream("Tell me a long story")) {
  process.stdout.write(chunk.content);
}
```

### Structured Output (Zod)

Stop parsing markdown. Get typed objects directly.

```ts
import { z } from "@node-llm/core";

const PlayerSchema = z.object({
  name: z.string(),
  powerLevel: z.number(),
  abilities: z.array(z.string())
});

const chat = llm.chat("gpt-4o-mini").withSchema(PlayerSchema);
const response = await chat.ask("Generate a random RPG character");

console.log(response.parsed.name); // Fully typed!
```

---

## 🛡️ Security Circuit Breakers

NodeLLM protects your production environment with four built-in safety pillars:

```ts
const llm = createLLM({
  requestTimeout: 15000, // 15s DoS Protection
  maxTokens: 4096, // Cost Protection
  maxRetries: 3, // Retry Storm Protection
  maxToolCalls: 5 // Infinite Loop Protection
});
```

---

## 🔌 Middleware System

NodeLLM 1.9.0 introduces a powerful lifecycle hook system for audit, security, and observability.

```ts
import { createLLM, PIIMaskMiddleware, UsageLoggerMiddleware } from "@node-llm/core";

const llm = createLLM({
  provider: "openai",
  middlewares: [
    new PIIMaskMiddleware(), // Redact emails/phone numbers automatically
    new UsageLoggerMiddleware() // Log structured token usage & costs
  ]
});

// All chats created from this instance inherit these middlewares
const chat = llm.chat("gpt-4o");
```

### Decisive Tool Safety

Middlewares can control the engine's recovery strategy during tool failures.

```ts
const safetyMiddleware = {
  name: "Audit",
  onToolCallError: async (ctx, tool, error) => {
    if (tool.function.name === "delete_user") return "STOP"; // Kill the loop
    return "RETRY"; // Attempt recovery
  }
};
```

---

## 🤖 Agent Class

Define reusable, class-configured agents with a declarative DSL:

```ts
import { Agent, Tool, z } from "@node-llm/core";

class LookupOrderTool extends Tool<{ orderId: string }> {
  name = "lookup_order";
  description = "Look up an order by ID";
  schema = z.object({ orderId: z.string() });

  async execute({ orderId }: { orderId: string }) {
    return { status: "shipped", eta: "Tomorrow" };
  }
}

class SupportAgent extends Agent {
  static model = "gpt-4.1";
  static instructions = "You are a helpful support agent.";
  static tools = [LookupOrderTool];
  static temperature = 0.2;
}

// Use anywhere in your app
const agent = new SupportAgent();
const response = await agent.ask("Where is order #123?");
console.log(response.content);
```

### ToolHalt - Early Loop Termination

Stop the agentic loop early when a definitive answer is found:

```ts
class FinalAnswerTool extends Tool<{ answer: string }> {
  name = "final_answer";
  description = "Return the final answer to the user";
  schema = z.object({ answer: z.string() });

  async execute({ answer }: { answer: string }) {
    return this.halt(answer); // Stops the loop, returns this result
  }
}
```

---

## 💾 Ecosystem

Looking for persistence? use **[@node-llm/orm](https://www.npmjs.com/package/@node-llm/orm)**.

- Automatically saves chat history to PostgreSQL/MySQL/SQLite via Prisma.
- Tracks tool execution results and API metrics (latency, cost, tokens).

---

## 📚 Full Documentation

Visit **[nodellm.dev](https://nodellm.dev/)** for:

- [Deep Dive into Tool Calling](https://nodellm.dev/core-features/tools)
- [Multi-modal Vision & Audio Guide](https://nodellm.dev/core-features/multimodal)
- [Custom Provider Plugin System](https://nodellm.dev/advanced/custom-providers)

---

## License

MIT © [NodeLLM Contributors]