Google's MathSolver JSON-LD validator is stricter than schema.org. I learned that the hard way over 4 rounds of fixes.

Last week, Google Search Console flagged 10 pages on my Indian tax calculator suite with structured-data errors: Missing field usageInfo — 10 items Invalid value in field itemtype — 10 items The pages all had MathSolver JSON-LD blocks. I had 38 similar blocks across the site. The natural assumption: