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DingDuff Installation & Help

DingDuff is a legal-research connector for Claude. It links your own Claude account to a database of millions of court opinions, federal and state statutes and rules, and federal court filings (PACER) — so you can do real legal research right inside Claude, with citations.

This wiki is written so you can either read it yourself or point Claude at it and ask Claude to walk you through everything. The easiest path:

Open Claude, paste the link to this page, and say: "Walk me through installing DingDuff, one step at a time."

Pages in this wiki

• Install DingDuff (this page) — the main setup, start to finish.
• Browser Setup — extra steps if you use Claude in a web browser instead of the desktop app.
• Team & Enterprise — what to do if you're on a work plan and can't add the connector.
• Troubleshooting — fixes for common problems (a tool isn't working, you can't sign in, etc.).
• Skills & Settings — optional add-ons that make DingDuff noticeably better.
• How Citation Checking Works — what the cite-checker does, and the design behind its reliability and privacy.

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Before you start

DingDuff itself is free while in beta. To use it you need three things:

1. Your own Claude account — a paid plan (Pro, Max, Team, or Enterprise) is recommended. The Claude desktop app with Cowork mode is the best experience; a web browser also works (see Browser Setup). (The Free plan technically works but allows only one custom connector.)
2. A DingDuff login — sign up at https://dingduff.com to create your account. This gives you the email + password you'll use when connecting. DingDuff is for licensed attorneys (per the Terms of Service).
3. Your own Anthropic API key (BYOK) — needed to unlock two of the tools. You add this after connecting (Step 4 below). Typical cost is ~$5–10/month, paid to Anthropic, not to DingDuff.

If you haven't created a DingDuff account yet, do that first at https://dingduff.com (click Sign Up). You'll need that email and password during Step 2.

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Install DingDuff

These steps are for the Claude desktop app (recommended). If you're in a browser, do these same steps and then read Browser Setup for the one extra setting browsers need.

Step 1 — Open the connector settings

1. In Claude, open Customize from the left sidebar.
2. Go to Connectors.
3. Click the + button, then choose Add custom connector.

On a Team or Enterprise plan, you may not see "Add custom connector" — only an organization owner can add it. If so, go to Team & Enterprise.

Step 2 — Add DingDuff

1. In the dialog, give it a name (e.g., DingDuff).

2. In the URL field, paste exactly:

   https://app.dingduff.com/mcp
   

3. Click Add.

4. Claude will send you to the DingDuff sign-in page. Enter the email and password for the DingDuff account you created at dingduff.com, then approve the connection. You'll be returned to Claude automatically.

A small browser/login window normally opens for sign-in. If nothing appears, see "Sign-in window doesn't open" in Troubleshooting.

Step 3 — Allow DingDuff's tools

After connecting, DingDuff appears in your connector list with its tools. We recommend setting each tool to always allow (the checkmark, not the hand icon) so you aren't asked for permission on every research request.

Step 4 — Add your Anthropic API key (unlocks the last two tools)

Everything works at this point except two tools — opinion_extract and submit_batch_screen — which stay locked until you add your own Anthropic API key. To set it up:

1. Open a new chat and confirm DingDuff is connected.
2. Ask Claude: "Help me get an Anthropic API key so I can add it to DingDuff." Claude will point you to the Claude Console (console.anthropic.com).
3. In the Console, add a payment method, create an API key, and copy it.
4. Log in to your profile on dingduff.com and paste the key into the field provided.

Two safety rules (required by our Terms):

• Use a dedicated key for DingDuff only — so you can revoke it without affecting anything else.
• Turn off auto-reload on that key, so any exposure stays capped.

Step 5 — Confirm it works

First confirm the connector is live. In a chat, ask Claude:

"Does the DingDuff connector have the opinion_search tool?"

If yes, the connector is working. Then confirm your API key (Step 4) took effect:

"Does the DingDuff connector have the opinion_extract tool?"

opinion_extract and submit_batch_screen only appear after you add your API key — if they're missing, go back to Step 4. Everything else works without a key.

Now try a real query, e.g.:

"Using only DingDuff, find recent Texas appellate cases on the economic loss rule and give me citations."

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Recommended settings (optional but worth it)

These take a few minutes and noticeably improve results. Full details on Skills & Settings:

• Install the research skills (dingduff-case-law-research-standard is the best default) — they improve the quality of research answers.
• Install the dingduff-citation-check skill — verifies every citation in a drafted memo against the stored sources.
• Add a custom instruction (Profile → Instructions for Claude) telling Claude to always use DingDuff for legal research, so you don't have to ask each time.
• Turn off chat training in your Claude privacy settings.

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Using DingDuff on mobile

You can add the DingDuff connector on the Claude mobile apps the same way (Connectors → add the custom connector → sign in), and research tools (searching and viewing cases, statutes, and PACER) work fine.

However, the features that need a working file environment — saving sources (opinion_store / statute_store) and the citation-check skill — rely on the desktop app or browser. For full functionality, use the desktop app (Cowork) or a browser; treat mobile as read-and-research on the go.

Quick fixes

• A DingDuff "store" tool says it worked but no files appear → you likely need to turn on network access for Claude's tools. See Troubleshooting → Opinion/statute store tools don't work.
• You can't find "Add custom connector" → you may be on a Team/Enterprise plan; see Team & Enterprise.
• opinion_extract is missing or fails → you haven't added your API key yet; redo Step 4 above.

For everything else, see Troubleshooting.