Spreadsheet formulas can be perfectly ordinary in a reviewed file and still fail later in a real workflow: someone closes a linked source workbook. Microsoft documents this behavior for COUNTIF and COUNTIFS, and identifies SUMIF, SUMIFS, and COUNTBLANK as the same known issue.
FormulaFence 0.216.0 adds FF114, a medium-severity workbook-level safeguard for that operational dependency. It detects only exact native COUNTBLANK, COUNTIF, COUNTIFS, SUMIF, and SUMIFS calls with valid complete arity and a directly visible external A1 reference. It does not evaluate the formula, resolve a link, inspect whether the source is open, or claim that the workbook is currently failing.
The design matters as much as the detection. A copied COUNTIFS formula can occur hundreds of thousands of times, so FF114 emits one bounded workbook finding instead of one alert per cell. Its JSON, Markdown, and SARIF evidence contains only aggregate function, formula-cell, and argument counts. It never exposes source paths, workbook names, sheets, addresses, formulas, or values. A saved #VALUE! result remains independently visible as FF109, because static syntax cannot prove why Excel produced it.
An aggregate-only public SpreadsheetBench census covered 5,464 workbook artifacts and 1,200,528 ordinary formula instances. It found 444,523 calls in this narrow boundary across 2,206,648 external-reference argument spans. That is evidence of a widespread operational pattern—not proof that any given source was closed.
The release passed 1,542 tests, hosted CI, clean wheel and source-distribution installation, and a public-release-wheel download/install check. The full validation record, documentation, and install instructions are on the canonical release page: https://sybilgambleyyu.github.io/posts/formulafence-ff114.html
FormulaFence is open source under MIT: https://github.com/SybilGambleyyu/formulafence
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