Lexiel inside Claude and ChatGPT
https://api.lexiel.ai/mcpOAuth authentication with your Lexiel account. Nothing installed on your machine.
What you can do for free
25 queries a day, no credit card.
Search case law
Returns the exact paragraph to cite, from the verified corpus (CENDOJ, Constitutional Court, CJEU).
Verify citations
Checks any law or ruling against Spain's BOE and CENDOJ before it reaches your brief.
Audit a short brief
Flags every unconfirmed citation in a document up to 6,000 characters.
Search legislation
Finds the exact article in Spain's official gazettes.
- Full judgment text
- Long brief audits (no character limit)
- LO 1/2025 procedural compliance (competent court, MASC)
- Expanded search results (20 vs 5)
Connect it in under 3 minutes
Claude Desktop
- 1Open Claude Desktop → Settings → Connectors.
- 2Click "Add custom connector".
- 3Paste the URL above (https://api.lexiel.ai/mcp) and give it a name, e.g. "Lexiel".
- 4Authorize access with your Lexiel account when prompted (OAuth).
- 5Done: ask Claude to search case law or verify a citation.
ChatGPT
- 1Settings → Apps & connectors → Advanced settings → turn on Developer mode.
- 2Go back to Apps & connectors → "Create connector".
- 3Paste the URL above (https://api.lexiel.ai/mcp) and choose OAuth authentication.
- 4Authorize access with your Lexiel account.
- 5In every chat where you want to use it: "Add sources" → select Lexiel.
Steps verified as of August 2026; Claude and ChatGPT menu names may change over time.
Remote server with OAuth authentication (you never share your password with Claude or ChatGPT). Available tools depend on your plan; the free quota is shared at the account level and resets daily.
FAQ
What is the Model Context Protocol (MCP)?
MCP is an open standard (created by Anthropic, also adopted by OpenAI) that lets an AI assistant like Claude or ChatGPT connect to external tools and data in real time. In practice: it gives your AI access to Lexiel's verified legal corpus without leaving the conversation.
Do I need to install anything on my computer?
No. Lexiel's MCP server is remote (not local): you add a URL in Claude or ChatGPT's settings and authenticate with your Lexiel account (OAuth). There's no executable or server configuration involved.
What happens if I go over the 25 daily queries on the free plan?
The tool responds with a clear notice (never an opaque error) explaining that the daily quota is exhausted and which paid plan expands it. The quota resets every day at midnight.
Does it work the same in ChatGPT as in Claude?
The server and tools are the same; what changes is where you activate it. In Claude Desktop: Settings → Connectors → Add custom connector. In ChatGPT: Settings → Apps & connectors → Developer mode → Create Connector, then enable it per chat via "Add sources".
Is this the same as other free legal MCP connectors?
Not exactly. There are free legal MCP connectors focused only on searching and verifying rulings (for example Jurisprudenciator, with a more generous free quota than ours). Lexiel's difference is that the MCP is the entry point to a full platform: when you need to draft the brief, manage the case, invoice with VeriFactu or work across 19 other jurisdictions, you're already in the same account.
Ready to connect it?
Free account, no card. 25 queries a day.