Program tier

Checks that need only the Python standard library. They run on every push. A finding is an error when it is certain, a warning when it comes from a heuristic, and a judgment question when no program can decide.

Check	What it verifies	Guarantee
bibliography_keys.py	Bibliography keys: a key names one work, and a work carries one key, in the bibliography and across its family	Exact for a key held twice, in one file or across the family, when the rows' links name their works; one work at two addresses reads as two, so a clash is cleared by giving both rows one link. Heuristic for one work under two keys: a work cited by a DOI in one row and by its preprint in another is seen as one only when a row names both.
changelog_pin.py	Changelog pin: the newest pin line of an extension's changelog names the release its workflows check out	Exact for a pin line written as the form gives it.
citations.py	Citations: every work cited in the text has one entry in the bibliography, and every entry is cited	Heuristic: a capitalised word before a year can be a false citation ("Colon Classification 1933"); config lists words that never start one.
co_change.py	Co-change: files that keep changing together should sit together	Coupling in history is evidence, not proof, so every finding is judgment.
cross_file_terms.py	Short reference distance across files: a term defined in one file is linked where another uses it	Heuristic.
decision_records.py	Decision records: every record in decisions/ follows the four rules of the decision-record shape	Exact, except rule 3.
defined_before_use.py	Define before use: a term is not used in a file before the line that defines it	Heuristic: bold is also used for emphasis, and a term can be defined in another file.
duplication.py	Duplication: the same run of words held in two files means one fact kept in two places	Exact for the copy; whether the copy is a fact or a quotation is judgment.
judgment_quotes.py	Judgment quotes: every answer in the answers file quotes the file it answers for, and every quote is really there	Exact for the presence of each quote; whether the quote supports the answer is judgment.
links.py	Links: every relative link in a markdown file resolves to a file or folder that exists	Exact for file links.
logical_lines.py	File size: a trigger on logical lines and a ceiling on physical lines, each asking a question	The sentence count is a heuristic (abbreviations split badly).
long_sentences.py	Long sentences: a sentence past max_words words is the cheap sign of packed information	Heuristic.
name_matches_title.py	Names predict content: the words of a file's name appear in its title or opening	Heuristic.
outline_depth.py	Outline depth: a document's headings stay within three levels	The count is exact; the limit of three is a convention, so a deeper heading warns.
overview_first.py	Overview first: a long document opens with what it is and how it is organised, not with a heading	Heuristic (the opening may be there and still not be an overview).
paragraph_length.py	Signal the structure: no wall of prose, and no long run without a heading	Heuristic.
portable_paths.py	Portable paths: every path must check out on filesystems other than the one it was made on	Exact.
principle_coverage.py	Principle coverage: every principle names at least one check that exists, so CI tests every rule	Exact.
provisional_tags.py	PROVISIONAL tags: a value marked as a guess is measured, or kept knowingly, before it ages	Exact for the date.
readable_measure.py	Readable measure: the site's stylesheet sets body text inside the measured ranges	Exact for the declared values; the rendered line still depends on the face.
references.py	References: every DOI, arXiv id, GitHub repository and web link cited resolves	Exact offline. Online depends on remote servers (a timeout is reported as a warning, never hidden).
release_version.py	Release version: the citation file names the release the changelog ends on, with its date	Exact for a heading written as Keep a Changelog writes it.
shape_conformance.py	Shape conformance: a document declared to be of a shape holds the parts that shape requires	Exact.
shape_example.py	Shape example: a shape links at least one filled example of itself, and the example links back to the shape	What a run with no warning guarantees: every declared shape points to at least one document that declares it follows that shape. What it does not: that the example is good, complete, or written with real content rather than placeholders (judgment).
standard_card.py	The repository's generated indexes: the principle table in standard.md, llms.txt, and the check tables	Exact.
standard_links.py	Standard links: every link from the text into the standard names the commit the workflows pin	Exact for links written [text](target).
standard_pin.py	Standard pin: every workflow checks out the standard at one commit, so one bump moves the checks and the site together	Exact for a checkout step written on separate lines, as the template writes it; a step in flow style (with: {repository: ...}) is not read.
sufficient_contrast.py	Sufficient contrast: every text colour reaches a WCAG ratio of 4.5:1 on the background it sits on	Exact for colours declared in the same rule; heuristic for inherited backgrounds. A colour is read as hex, or as white or black; any other form is skipped. The rendered page is not measured.
tree_shape.py	Tree shape: folders stay browsable, and dependencies between folders never form a cycle	Exact for breadth, depth and static imports; dynamic imports are invisible.
type_buckets.py	Type buckets: no folder is named for a kind of file instead of what its files serve	Exact.