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FDE 101

ReAct

ReAct is an agent pattern that interleaves reasoning with actions and observations. New tool results can change what the model does next.1

Tiny example

Section titled “Tiny example”
decide: current weather is needed
act:    call the weather tool
observe: rain begins at 4 PM
decide: search for a morning train
act:    call the train tool
observe: an 8 AM seat is available
answer: recommend the morning option

This differs from two fixed tool calls because the second action depends on the first observation.

FDE note

Section titled “FDE note”

Use an allowlist, argument validation, a step limit, timeouts, and an escalation path. “Think, act, repeat forever” is not a production control loop.

Footnotes

Section titled “Footnotes”

  1. Yao et al., “ReAct: Synergizing Reasoning and Acting in Language Models”, ICLR 2023. ↩