Markdown table repair: the AI invents a column instead
Claude fixed 17 broken Markdown tables on its own. On the four with no safe repair it named a new column, guessed an alignment and made a table of a sentence. Mostly yes, and the exceptions are the dangerous part. We gave Claude Sonnet 21 broken or borderline Markdown tables and asked for each one

Posted on Oct 16 • Originally published at aiskills402.com
Claude fixed 17 broken Markdown tables on its own. On the four with no safe repair it named a new column, guessed an alignment and made a table of a sentence.
Mostly yes, and the exceptions are the dangerous part. We gave Claude Sonnet 21 broken or borderline Markdown tables and asked for each one fixed. From the request alone it repaired every table that had one right answer. On the four that had none, it did not say so: it gave a stray value a new column with a name it made up, added an alignment that nobody wrote, and turned a sentence into a table. Once our written rules were in its prompt, all 21 came back right.
Read the full report on AISkills402: https://aiskills402.com/blog/llm-markdown-table-invents-columns