Citation Checking

How Citation Checking Works

DingDuff's citation checker takes a piece of legal writing you've drafted, checks every citation in it against the actual source text, and opens a review panel where you — the attorney — give the final word on each one. It then produces a printable audit record for the file. This page explains what it can do and the design choices that make it reliable and private. To install it, see Skills & Settings.

What it can check

Any legal writing that cites authority — a brief, motion, memorandum, demand or opinion letter, or any block of text with citations. Hand it your document as Markdown, Word (.docx), Google Docs (downloaded as .docx), or a text-based PDF.

It checks those citations against:

• Authorities you pulled from DingDuff — opinions and statutes you saved with the opinion_store and statute_store tools.
• Any source you supply yourself — a Restatement section, a case that isn't in CourtListener, the opposing party's brief, a factual exhibit: any text-based file you drop into your working folder. Citation checking is not limited to DingDuff's library.

And it produces:

• An interactive review panel showing your document on one side and each cited source on the other, with the supporting passage highlighted.
• Your recorded verdicts on each citation.
• A printable audit log for the file and the court.

How it stays reliable

The job of the tool is to confirm a citation actually says what your draft claims — and to do it in a way you can trust.

• Quotes are verified by code, not by the AI's memory. Claude proposes the passage that supports each point, but a small program running in your own session then searches the real source file for that exact text. If the text isn't there, it can't be marked as supported. A made-up or misremembered quote can't slip through as a verified highlight. The matching is forgiving about formatting — spacing, curly vs. straight quotes, hyphenation across line breaks — so honest quotes aren't flagged over cosmetic differences.
• It shows you the evidence, not just a verdict. For every citation you see the claim, the exact highlighted passage in the source, and your document side by side — so you can judge it yourself instead of taking the tool's word for it.
• You give the final verdict — and there are three. On each citation you mark it verified, needs attention (supported, but with a caveat you note), or rejected. The tool flags the ones that deserve scrutiny — a quote it couldn't find, a quote that turned out to be from a different case, or a source you never provided — but the attorney is always the guardrail. That's DingDuff's whole philosophy: the lawyer checks the work, so the tool never pretends to be infallible.

How it protects your privacy

Legal drafts are confidential, so the design keeps your work on your machine as much as possible:

• The checking itself is entirely local. The program that matches quotes to sources runs in your own session and sends nothing anywhere.
• The interactive review panel passes your document and the cited excerpts through the DingDuff server once — only as the arguments needed to draw the panel — and they are never stored or logged. If you'd rather nothing transit at all, the tool also generates a standalone review.html you can open locally; that version never leaves your machine.
• Sources you supply are handled locally, and the only thing sent back into the chat is your own verdicts, as text, when you choose to send them.
• Everything lands in your working folder (the verification results, your verdicts, the audit log), and you can delete any of it whenever you like. DingDuff keeps no copy of your document or your verdicts.

How to use it

1. Draft your document — brief, motion, letter, memo — in any format.
2. Save the sources it cites. Use opinion_store / statute_store for DingDuff authorities; for anything else, drop a text copy into your working folder.
3. Ask Claude to cite-check it (e.g., "cite-check this brief"). Claude reads your draft, lines each citation up with its source, and runs the local verifier.
4. Review in the panel. Step through each citation, read the highlighted support, and mark it verified / needs attention / rejected, adding a note where useful — then send your verdicts back.
5. Revise if needed and re-run — citations you've already cleared carry their verdicts forward automatically.
6. Generate the audit log — a printable record of what was checked, the verdicts, and who reviewed it, for the file.

You'll need python3 available (Cowork and Claude Code include it). To install the skill, see Skills & Settings; if a step fails, see Troubleshooting.

What it does not do

Citation checking confirms that a cited source actually contains the language and supports the point your draft relies on. It does not tell you whether an authority is still good law (overruled, abrogated, superseded) — use the research skills for that — and it doesn't replace your professional judgment about whether an authority fits your argument.