LawDiver MCP

Investiga opiniones legales verificadas en 10 millones de casos, además de estatutos, impuestos y laboral.

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API · MCP

LawDiver API and MCP

This page covers how to use LawDiver from your own software or from an AI assistant. You can call a REST API directly, or connect Claude, ChatGPT, and other MCP clients so they search and retrieve from LawDiver instead of inventing cites from memory.

Create a free account API documentation

LawDiver offers four research surfaces: general U.S. caselaw, federal tax, federal trademark, and immigration. Each surface is available on the website, over MCP for AI assistants, and over a dedicated REST API for applications you build.

Claude and ChatGPT have official or directory listings for some of these surfaces. Where a listing is live, install from that listing. Where it is not, the guides below show the manual connector or Custom GPT Action path. The sections that follow explain what each option covers and link to the full setup page.

What is an API?

An API (application programming interface) lets your own software call LawDiver over HTTPS. You send a search or a citation, and LawDiver returns structured JSON — case metadata, opinion text, cite-check results, or specialty authorities. You choose when to call it and how to show the answer in your product.

LawDiver issues product-scoped keys (for example ld_live_ for caselaw, ld_tax_ for tax). The same key can also authenticate header-based MCP clients. Full field reference lives in the API documentation.

What is an MCP?

MCP (Model Context Protocol) lets an AI assistant call LawDiver as a tool while you chat. Instead of guessing a case cite, the model can search the corpus, open an opinion, or check a citation, then answer from what came back.

LawDiver hosts MCP over Streamable HTTP. Caselaw is at https://lawdiver.com/mcp. Tax, trademark, and immigration each have their own server URL and tools. Claude.ai and ChatGPT often use OAuth (sign in and Allow). Editors such as Cursor usually send an API key in a header.

LawDiver for Claude

Active — LawDiver is listed in the Claude directory. Connect once, then turn the connector on for each chat.

Gives Claude search, retrieval, and cite-check over more than 10 million U.S. opinions, plus statutes and specialty cite resolve where the corpus holds them. This is the caselaw connector, not Tax or Trademark.

Install from the Claude directory, sign in to LawDiver, and click Allow. No API key paste on claude.ai.

Claude setup guide →

LawDiver for OpenAI

Active — LawDiver is an officially approved ChatGPT app. Install from the ChatGPT listing; do not paste a key into chat.

Same caselaw research tools as the Claude connector: search cases, open opinions, and check citations against the live corpus while you work in ChatGPT.

Install LawDiver for ChatGPT, sign in, and click Allow.

ChatGPT setup guide →

LawDiver with an API

Call search, retrieval, cite-check, and bulk upload from your own application. Licensed for any commercial purpose — your desk, your firm, or a product you ship. Coverage includes more than 10 million U.S. court opinions, 60,000 U.S. Code sections, the Code of Federal Regulations, over 1.9 million state statutes, federal and state court rules, U.S. and state constitutions, and specialty corpora (IRS tax authorities).

Authenticate with an ld_live_ key. Endpoints live under /api/v1. The product page summarizes commercial use and endpoints; the docs cover every field.

Caselaw API product page →

Full API documentation →

LawDiver Tax for Claude

Active — LawDiver Tax is approved in the Claude directory (separate from caselaw LawDiver).

Tax research over a dedicated corpus and five MCP tools at https://lawdiver.com/mcp/tax. What you can reach:

  • IRC and Treasury regulations year by year ( 1985 – 2026; about 2,300 Code sections and 15,000 reg sections held).
  • About 59,000 IRS guidance items (Rev. Rul., Rev. Proc., notices, announcements, T.D.s, PLRs, and related Chief Counsel material) with status checks.
  • More than 64,000 Tax Court and 28,000 BTA opinions, plus about 57,000 other searchable federal tax cases.
  • Forms and instructions, tax treaties, and IRS guidance citator checks.

REST mirrors the same work: POST /api/v1/tax/search, /retrieve, /case, /treaty, /check. Keys use the ld_tax_ prefix.

Open LawDiver Tax in the Claude directory.

Tax for Claude setup guide →

LawDiver Tax for OpenAI

Not yet listed as an official ChatGPT Tax app. Same Tax corpus and endpoints as above; use the free web product or a Custom GPT Action until the listing ships.

You get the same Tax access described in LawDiver Tax for Claude. On OpenAI, wire a Custom GPT Action to /api/v1/tax/* with an ld_tax_ key in Action auth settings — never paste the key into a chat message. Or research on /tax and paste verified text into ChatGPT with a hard cite boundary.

Tax for ChatGPT setup guide →

LawDiver Tax API

Same Tax corpus as above, called from your code with ld_tax_ keys. Caselaw ld_live_ keys do not open /api/v1/tax/*.

Tax API reference →

LawDiver Trademark for Claude

Active — LawDiver for Trademark is approved in the Claude directory (separate from caselaw and Tax).

Trademark research at https://lawdiver.com/mcp/trademark. What you can reach:

  • USPTO mark records and application / registration matter files.
  • Examination briefs, responses to office actions, appeal briefs, and TTAB decisions — searchable by Nice use class and by boolean, semantic, or hybrid search.
  • TMEP and TBMP manuals.
  • Federal trademark and TTAB caselaw with good-law signals, indexed against the PTO corpus.

REST: POST /api/v1/trademark/search, /retrieve, /case, /matter, /topics. Keys use ld_tm_.

Open LawDiver for Trademark in the Claude directory.

Trademark for Claude setup guide →

LawDiver Trademark for OpenAI

Not yet listed as an official ChatGPT Trademark app. Same Trademark corpus as above; use the web product or a Custom GPT Action until the listing ships.

Same access as LawDiver Trademark for Claude. On OpenAI, point a Custom GPT Action at /api/v1/trademark/* with an ld_tm_ key in Action auth, or work side by side with /trademark.

Trademark for ChatGPT setup guide →

LawDiver Trademark API

Same Trademark corpus as above, from your application with ld_tm_ keys under /api/v1/trademark/*.

Trademark API reference →

LawDiver Immigration for Claude

Not yet in the Claude directory. Add a custom connector pointing at https://lawdiver.com/mcp/immigration, or use an ld_imm_ key in header-based clients.

Immigration research over a dedicated MCP server. What you can reach:

  • USCIS Policy Manual, Foreign Affairs Manual (FAM / FAH), INA, and 8 C.F.R.
  • AAO, OCAHO, and BALCA materials (AAO non-precedent decisions are not binding).
  • Precedential BIA and Attorney General decisions (I&N Dec.) and linked federal petitions for review.
  • Stored Visa Bulletin months and category history from held text only.

Tools: immigration_search, immigration_retrieve, get_immigration_case, check_immigration_authority, get_visa_bulletin. REST mirrors those under /api/v1/immigration/* with ld_imm_ keys.

Immigration for Claude setup guide →

LawDiver Immigration for OpenAI

Not yet listed as an official ChatGPT Immigration app. Same Immigration corpus as above; use the web reader or a Custom GPT Action.

Same access as LawDiver Immigration for Claude. On OpenAI, wire a Custom GPT Action to /api/v1/immigration/* with an ld_imm_ key, or research on /immigration.

Immigration for ChatGPT setup guide →

LawDiver Immigration API

Same Immigration corpus as above, from your code with ld_imm_ keys under /api/v1/immigration/*.

Immigration API reference →

Other Integrations

Cursor, Claude Code, Perplexity, Codex, OpenCode, and other MCP clients can use the same servers. Caselaw is at https://lawdiver.com/mcp; specialty servers append /tax, /trademark, or /immigration. Most editors send Authorization: Bearer with the matching key prefix. Perplexity can use OAuth on a paid plan.

Pick an agent below for copy-paste steps.

Which agent are you using?

Choose your agent for the best setup instructions.

  • OCOpenClaw
  • HAHermes Agent
  • CClaude.ai
  • GPTChatGPT
  • PxPerplexity
  • CCClaude Code
  • CxCodex
  • GGrok Bot
  • OOpenCode
  • CuCursor
  • …Other
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