Check whether every month in a folder span is present.

Read-only. Names a folder and optionally a period range such as 'January 2024 to December 2025' or 'last 12 months'.

Check whether a document's figures still match a source file the caller names.

Read-only. Does not search for a plausible match — both paths are required. Returns UNCHECKABLE when recorded facts are missing and cannot be read.

List which reporting periods a folder holds from dated filenames.

Read-only. Helps an agent decide what to ask next.

Check what a task required against what was actually read, over any two sets of keys.

Read-only, and touches no filesystem — the caller holds both lists. Use this when the thing you must account for is not dated files in a folder: documents the question spans against the chunks a retriever returned, files changed in a pull request against files reviewed, table partitions against partitions loaded, required controls against controls with evidence, declared eval cases against cases actually run.

expected is the caller's declaration and is never inferred here. scope names the items for the sentence ("documents the question spans"); where names where they were looked for ("the retrieved set"); derivation records how the expected set was arrived at, so a reader can disagree with the denominator rather than only with the result.

Returns the coverage record: complete, read of required, and each way an expectation failed to be evidence kept separate. Anything present that was not expected is reported under unexpected and deliberately earns no credit against the denominator.