ReAct: Reasoning and Acting
The ReAct pattern interleaves reasoning steps with action steps — the agent thinks about what to do, does it, observes the result, and reasons about the next step. Most enterprise agents run ReAct whether or not they call it by name.
What Is the ReAct Pattern?
ReAct (Reasoning and Acting) is the foundational agentic design pattern that interleaves reasoning steps with action steps. The agent thinks about what to do (Reason), takes an action (Act), observes the result, thinks about what the result means and what to do next, and continues until the goal is achieved or it determines it cannot proceed.
Most enterprise agents run a version of ReAct without explicitly naming it. Understanding the pattern helps you debug agents that get stuck, design better prompts, and set appropriate expectations for what agents can and can't do.
When to Use It
- Tasks that require multiple tool calls in sequence, where each step depends on the previous result
- Tasks where the right path isn't known in advance — the agent needs to explore before it can act
- Debugging-type tasks where the agent must identify the problem before solving it
When NOT to Use It
- Simple single-tool tasks where reasoning is unnecessary overhead
- Tasks with a fully defined sequence — use Plan-and-Execute instead
- Real-time response requirements — ReAct's iterative loop adds latency
How It Works
The agent alternates between Thought (reasoning about the situation and what to do), Action (calling a tool or taking a step), and Observation (the result of the action). This loop continues until the goal is achieved. In Workato's Agent Studio, this loop is implemented by the Genie's reasoning engine, which manages the thought-action-observation cycle automatically.