Tin Rabzelj
Tin Rabzelj
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ReAct: Synergizing Reasoning and Acting in Language Models | Paper Notes

8/27/2025

https://arxiv.org/abs/2210.03629

"ReAct" approach is a framework that enables LLMs to solve complex tasks by dynamically combining internal reasoning with external actions. The model generates both reasoning traces and task-specific actions in an interleaved way.

One limit of CoT is that their reasoning is static. It cannot interact with the external world to update their knowledge or verify their thoughts. This can lead to error propagation or hallucinations. "Acting-only" models generate actions but they can't do high-level planning.

ReAct addresses these issues by prompting the LLM to generate a sequence of thoughts, actions, and observations. That creates a loop for solving problems:

  • Thought: The model first reasons about the task. It analyzes the current situation, decomposes the goal into smaller steps, and comes up with a plan.
  • Act: Based on that, the model generates an action to be executed in the environment.
  • Observation: The model receives an observation from the environment as a result of its action. This provides feedback.

This "Thought => Act => Observation" cycle repeats, and the model adjusts its plan. This synergy is described in the paper as:

  • Reason to Act: The reasoning traces help the model update high-level plans.
  • Act to Reason: The actions allow the model to interface with external sources to improve its reasoning.

8/27/2025

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