Solon 4.0 ReActAgent: A Practical Guide to Building AI Agents That Think and Act

If you've ever wanted an AI that doesn't just chat but actually does things — queries databases, calls APIs, makes decisions, and learns from results — you're in the right place. In this tutorial, I'll show you how to build production-ready AI agents using Solon 4.0's ReActAgent . By the end, you'll have built an agent that can reason through complex problems, use external tools, and adapt its behavior based on real-world feedback. What Makes ReActAgent Different? Traditional LLMs are great at generating text, but they hit a wall when they need to interact with the real world — checking a database, fetching live data, or performing calculations. ReActAgent (Reason + Act) breaks through that wall. It implements a cognitive loop: Thought → Action → Observation → (repeat or finish) The agent thinks about what to do next, acts by calling a tool, observes the result, and decides whether to continue or deliver the final answer. This isn't just theory. Solon's ReActAgent has been used in production for automated customer support, intelligent data analysis, and multi-step workflow automation. 1. Adding the Dependency First, add the solon-ai-agent module to your project: <dependency> <groupId> org.noear </groupId> <artifactId> solon-ai-agent </artifactId> </dependency> Note : If you're using Solon's parent POM, the version is managed automatically. Otherwise, use the latest Solon version. 2. Building a ChatModel (The Agent's Brain) Every agent needs a "brain" — a ChatModel that powers reasoning. Let's build one using the fluent API: import org.noear.solon.ai.chat.ChatModel ; ChatModel chatModel = ChatModel . of ( "https://api.moark.com/v1/chat/completions" ) . apiKey ( "your-api-key-here" ) . model ( "Qwen3-32B" ) . build (); You can also configure it via YAML and inject it: solon.ai.chat : demo : apiUrl : " http://127.0.0.1:11434/api/chat" provider : " ollama" model : " llama3.2" @Inject ( "${solon.ai.chat.demo}" ) ChatConfig chatConfig ; ChatModel chatModel = ChatModel . o