DingDuff plugin
A free legal-research connector for Claude: US court opinions and statutes, PACER filings and citation checking.
- 64 ★ on the repository
- Last commit
Extended access
Why this level
- Queries, texts and client documents go to the external DingDuff service, and sign-in requires a personal account.
- A model's legal answer can be wrong, and the responsibility for checking stays with the lawyer.
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add plugins/dingduffDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- Queries, texts and client documents go to the external DingDuff service, and sign-in requires a personal account.
- A model's legal answer can be wrong, and the responsibility for checking stays with the lawyer.
This is third-party code. Review the repository files before installing.
What it does
DingDuff connects Claude to a database of American law: millions of court opinions, federal and state statutes and regulations, rules of procedure and federal court filings from PACER. A lawyer asks a question in plain words, and Claude searches the sources, reads full texts and answers with links that can be opened and verified. The toolset covers searching and reading opinions, citation analysis that shows who cites a case, browsing the structure of codes, and searching dockets and filings in PACER. In the Claude Cowork desktop app, copies of opinions and statute sections are saved to a folder on the computer. The repository holds five free skills: legal research, analysis, validity check, citation check and citation formatting. For Claude Code they install as a plugin together with the connector.
Who it is for. US practicing lawyers who litigate and draft memos and want to find precedent through Claude rather than by building Boolean queries.
Good fit when
- You need recent Ninth Circuit cases on the economic-loss rule.
- Before citing a case you must confirm it is still good law for your proposition.
- A finished memo in Word or Markdown is being checked: every citation is verified against the source text.
- A case needs its PACER docket found, individual filings opened and searched.
- Citations are brought to the form courts expect: signals, pincites and short forms.
Not a fit when
- You are not a licensed attorney: the terms of service are meant for practicing lawyers.
- You need the law of another country: the database covers US courts and statutes.
- The result must go to court without review: Claude can be wrong and the lawyer is the check.
Example request
Find recent Ninth Circuit cases on the economic-loss rule, check that they are still good law and cite only DingDuff sources.Limitations
Your own Claude plan, preferably paid, and a DingDuff account at dingduff.com are required. On the free Claude plan only one custom connector is allowed. To save sources in the Claude web app, enable code execution and network access, while on a phone searching and reading work without file saving. Citation checking requires `python3`. The DingDuff Skills License 1.0 allows any personal use and forbids commercial redistribution of copies. The authors warn that Claude sometimes errs, so a lawyer checks every opinion and citation.
How to disable. In Claude Code run `/plugin uninstall dingduff@dingduff`, and `claude mcp remove` for a manual connection. In the web app disable the connector and skills in settings.
FAQ
How do I connect DingDuff to Claude Code?
Run `/plugin marketplace add DingDuff/dingduff-public`, then `/plugin install dingduff@dingduff` and `/mcp`. Pick `dingduff` and sign in through the browser. The plugin installs the connector together with the skills.
How much does DingDuff cost?
The service is free: no subscription and no per-search fee. The authors rely on voluntary tips, linked at dingduff.com. You only need your own Claude plan and a DingDuff account.
Which databases are covered?
Opinions of federal courts and courts of all 50 states and the District of Columbia, federal and state statutes, rules of procedure and PACER filings. Opinions are largely drawn from CourtListener.
What do the repository's skills do?
Five skills: research, analysis, validity check, citation check and citation formatting after The Indigo Book. Research and analysis work as a pair, and the validity check narrows full checking to the cases an argument rests on.
How do I install a skill in the Claude web app?
Download the `.skill` file from the `dist/` directory and upload it under Settings, Capabilities, Skills on claude.ai. In Cowork the path is Customize, then Skills. To update, download the file again.
Discussion
No questions or reviews yet.
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README in short
The authors built the service for their own practice and deliberately did not wrap Claude in guardrails: it gets direct access to sources. The safeguard is the lawyer who reads and checks every answer.