Simon Willison’s Weblog

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25th November 2025

Tool Text Diff Tool — Compare two blocks of text to identify character-level differences between them. This tool uses a dynamic programming algorithm to compute the longest common subsequence and highlights removed text in red and added text in green for easy visualization of changes. The results are displayed character-by-character in a dedicated output section that clearly indicates what was deleted from the original text and what was inserted in the modified version.

This is a beat by Simon Willison, posted on 25th November 2025.

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