citation-verifier

A fabricated or misattributed citation is the one error a thesis cannot survive. This skill treats every citation as unverified until three checks pass: the key exists, the entry is real, and the claim is supported.

Level 1: every key exists

1. Extract cite keys from the document:
   • LaTeX: \cite{a,b}, \citep, \citet, \parencite, \textcite, \autocite, \footcite, and starred/optional-argument forms.
   • Markdown/Pandoc: [@key], [@a; @b, p. 3], @key.
   • Word: extract with pandoc file.docx -t markdown and look for Zotero fields or (Author, Year) strings; match those against .bib author+year.
2. Parse the .bib keys (^@\w+\{([^,]+),).
3. Report keys cited but not defined (hard error) and entries defined but never cited (informational; the bibliography should usually contain only cited works).

Level 2: every entry is real

For each cited entry:

1. If it has a doi: curl -s "https://api.crossref.org/works/<doi>" and compare title (normalised), first author surname, and year. A DOI that returns 404 is fabricated or mistyped: search CrossRef by title to find the real one and report both.
2. If it has an arXiv eprint: curl -s "http://export.arxiv.org/api/query?id_list=<id>" and compare title and first author.
3. If it has only a URL: curl -sI <url> returns 2xx/3xx; flag as weakly verified.
4. If it has none of these: curl -s "https://api.crossref.org/works?query.bibliographic=<title>&rows=3" and report whether a plausible match exists. Until it does, the entry is unverified.

Rate-limit to one request per second per host. Cache results in research/.citation-cache.json keyed by DOI so re-runs are fast.

A mismatch in title or author is reported as mismatched, with the fetched metadata beside the .bib entry, because it usually means the wrong DOI was attached to the right paper (or the right DOI to a paraphrased title).

Level 3: every claim is supported

This is the check that catches "the paper says X" when it does not. For each citation in context:

1. Take the sentence (or list item) that carries the cite and the claim it makes.
2. Open the matching note in research/notes/ (joined by key in the note's front matter). If there is a note, check whether the claim appears under One-sentence claim, Evidence, or Quotable. If there is no note, say so; the student should run paper-reader before citing.
3. Classify: supported (the note contains it), plausible but unverified (the note is silent), contradicted (the note's Limitations or Evidence say otherwise), or overclaimed (the note supports a weaker version, e.g. "improves" cited as "solves").
4. For a quotation, the exact text must appear in the note's Quotable section or in the source text; otherwise it is an unverified quote.

Report

Write research/citation-report.md and summarise in the reply:

# Citation report: chapters/02-related-work.tex (2026-09-21)

Cited keys: 41   Defined: 58   Missing keys: 1   Unused entries: 17
Verified: 36   Mismatched: 2   Unverified: 3   Claim checks: 30 supported, 8 unverified, 2 overclaimed, 1 contradicted

## Must fix
- `lee2022grading` is cited (line 112) but not in references.bib.
- `chen2021code`: DOI 10.1145/9999999 returns 404. CrossRef title search finds "..." with DOI 10.1145/3468264.3468563; confirm and replace.
- Line 87 cites `smith2023feedback` for "reduces grading time by half"; the note records a 23% reduction (Table 4). Overclaimed.

## Should check
- ...

Ordering: missing keys and dead identifiers first (they fail compilation or expose fabrication), then contradictions and overclaims, then the unverified.

Rules

• Never "repair" a citation by inventing a DOI, year, or venue. Report and propose; the student confirms.
• Never mark a claim supported because it sounds right. Supported means the note or source text contains it.
• Re-run before every submission. The citation-guard hook does Level 1 continuously on every edit; this skill does the rest.