Helios Engine - LLM Agent Framework

Helios Engine is a powerful and flexible Rust framework for building LLM-powered agents with tool support, streaming chat capabilities, and easy configuration management. Create intelligent agents that can interact with users, call tools, and maintain conversation context - with both online and offline local model support.

Key Features

• 🆕 ReAct Mode: Enable agents to reason and plan before taking actions with a simple .react() call - includes custom reasoning prompts for domain-specific tasks
• 🆕 Forest of Agents: Multi-agent collaboration system where agents can communicate, delegate tasks, and share context
• Agent System: Create multiple agents with different personalities and capabilities
• 🆕 Tool Builder: Simplified tool creation with builder pattern - wrap any function as a tool without manual trait implementation
• Tool Registry: Extensible tool system for adding custom functionality
• Extensive Tool Suite: 16+ built-in tools including web scraping, JSON parsing, timestamp operations, file I/O, shell commands, HTTP requests, system info, and text processing
• 🆕 RAG System: Retrieval-Augmented Generation with vector stores (InMemory and Qdrant)
• 🆕 Custom Endpoints: Ultra-simple API for adding custom HTTP endpoints to your agent server - ~70% less code than before!
• Streaming Support: True real-time response streaming for both remote and local models with immediate token delivery
• Local Model Support: Run local models offline using llama.cpp with HuggingFace integration (optional local feature)
• HTTP Server & API: Expose OpenAI-compatible API endpoints with full parameter support
• Dual Mode Support: Auto, online (remote API), and offline (local) modes
• CLI & Library: Use as both a command-line tool and a Rust library crate
• 🆕 Feature Flags: Optional local feature for offline model support - build only what you need!

Documentation

Online Resources

• Official Website - Complete interactive documentation with tutorials, guides, and examples
• Official Book - Comprehensive guide to Helios Engine
• API Reference - Detailed API documentation on docs.rs

Quick Links

• Getting Started - Installation and first steps
• Core Concepts - Agents, LLMs, chat, and error handling
• Tools - Using and creating tools
• Forest of Agents - Multi-agent systems
• RAG System - Retrieval-Augmented Generation
• Examples - Code examples and use cases

Local Documentation

• Getting Started - Comprehensive guide: installation, configuration, first agent, tools, and CLI
• Tools Guide - Built-in tools, custom tool creation, and Tool Builder
• Forest of Agents - Multi-agent systems, coordination, and communication
• RAG System - Retrieval-Augmented Generation with vector stores
• API Reference - Complete API documentation
• Configuration - Configuration options and local inference setup
• Using as Crate - Library usage guide

Full Documentation Index - Complete navigation and updated structure

Quick Start

Version 0.4.4

Install CLI Tool

# Install without local model support (lighter, faster install)
cargo install helios-engine

# Install with local model support (enables offline mode with llama-cpp-2)
cargo install helios-engine --features local

Basic Usage

# Initialize configuration
helios-engine init

# Start interactive chat
helios-engine chat

# Ask a quick question
helios-engine ask "What is Rust?"

As a Library Crate

Add to your Cargo.toml:

[dependencies]
helios-engine = "0.4.4"
tokio = { version = "1.35", features = ["full"] }

For local model support:

[dependencies]
helios-engine = { version = "0.4.4", features = ["local"] }
tokio = { version = "1.35", features = ["full"] }

Simple Example

use helios_engine::{Agent, Config, CalculatorTool};

#[tokio::main]
async fn main() -> helios_engine::Result<()> {
    let config = Config::from_file("config.toml")?;

    let mut agent = Agent::builder("MyAssistant")
        .config(config)
        .system_prompt("You are a helpful AI assistant.")
        .tool(Box::new(CalculatorTool))
        .react()  // Enable ReAct mode for reasoning before acting!
        .build()
        .await?;

    let response = agent.chat("What is 15 * 8?").await?;
    println!("{}", response);

    Ok(())
}

See Getting Started Guide or visit the Official Book for detailed examples and comprehensive tutorials!

Custom Endpoints Made Simple

Create custom HTTP endpoints with minimal code:

use helios_engine::{ServerBuilder, get, EndpointBuilder, EndpointResponse};

let endpoints = vec![
    // Simple static endpoint
    get("/api/version", serde_json::json!({"version": "1.0"})),
    
    // Dynamic endpoint with request handling
    EndpointBuilder::post("/api/echo")
        .handle(|req| {
            let msg = req.and_then(|r| r.body).unwrap_or_default();
            EndpointResponse::ok(serde_json::json!({"echo": msg}))
        })
        .build(),
];

ServerBuilder::with_agent(agent, "model")
    .endpoints(endpoints)
    .serve()
    .await?;

70% less code than the old API! See Custom Endpoints Guide for details.

Use Cases

• Chatbots & Virtual Assistants: Build conversational AI with tool access and memory
• Multi-Agent Systems: Coordinate multiple specialized agents for complex workflows
• Data Analysis: Agents that can read files, process data, and generate reports
• Web Automation: Scrape websites, make API calls, and process responses
• Knowledge Management: Build RAG systems for semantic search and Q&A
• API Services: Expose your agents via OpenAI-compatible HTTP endpoints
• Local AI: Run models completely offline for privacy and security

Built-in Tools (16+)

Helios Engine includes a comprehensive suite of production-ready tools:

• File Management: Read, write, edit, and search files
• Web & API: Web scraping, HTTP requests
• System Utilities: Shell commands, system information
• Data Processing: JSON parsing, text manipulation, timestamps
• Communication: Agent-to-agent messaging
• Knowledge: RAG tool for semantic search and retrieval

Learn more in the Tools Guide.

Project Structure

helios-engine/
├── src/                    # Source code
├── examples/               # Example applications
├── docs/                   # Documentation
├── book/                   # mdBook source (deployed to vercel)
├── tests/                  # Integration tests
├── Cargo.toml             # Project configuration
└── README.md              # This file

Contributing

We welcome contributions! See our Contributing Guide for details on:

• Development setup
• Code standards
• Documentation guidelines
• Testing procedures

Links

• Official Website & Book - Complete documentation and guides
• Crates.io - Package registry
• API Documentation - API reference
• GitHub Repository - Source code
• Examples - Code examples

License

This project is licensed under the MIT License - see the LICENSE file for details.

Made with love in Rust by Ammar Alnagar