Fermat 360

What Fermat 360 MCP server does

Fermat 360 MCP server gives supported AI clients access to Fermat 360, a legal research platform for Dutch law firms. It accepts questions about Dutch law and searches a corpus containing Dutch judgments, disciplinary decisions, national and local legislation, EU legislation, and judgments from the Court of Justice of the European Union and the European Court of Human Rights.

The service returns answers in Dutch. Each answer includes numbered citations linked to the source documents and passages used. ECLI numbers in answers are checked against the corpus. By default, searches include legislation currently in force. This makes the server relevant to the ⚖️ Legal category when an agent needs source-backed Dutch legal research rather than an uncited general response.

How it works

The hosted endpoint is available at https://fermat360.nl/mcp over streamable HTTP. Authentication uses OAuth 2.1 with PKCE. Clients identify themselves through a Client ID Metadata Document, and the connection does not use API keys. After signing in with a Fermat 360 account, the user approves the connection once and can later disconnect it from Fermat 360 settings.

The vraag_fermat tool submits a Dutch-law question. It can also continue an existing conversation by passing the relevant gesprek_id. A follow-up always causes a new search rather than relying only on the previous answer. The optional niveau setting is basis by default; extra produces a more thorough response and uses 10 units. If preparation is not complete, haal_antwoord retrieves the pending answer.

Setup and configuration

Add the remote endpoint in a supported client and complete the Fermat 360 approval flow. Claude users can add it as a custom connector. Claude Code can register it with claude mcp add --transport http fermat https://fermat360.nl/mcp, then authenticate through /mcp. In VS Code, add it with code --add-mcp '{"name":"fermat","type":"http","url":"https://fermat360.nl/mcp"}'; VS Code requests sign-in on first use. ChatGPT supports the endpoint through developer mode and an app configuration.

The service costs €100 per user per month excluding VAT. The one-week Fermat 360 trial does not include the connector. Questions share the account’s monthly allowance of 3,000 units: Basis uses one unit and Extra uses 10. Connector questions also appear in Fermat 360 chat history.

Limitations and notes

Fermat 360 MCP server is a hosted service; the repository contains its documentation, listing information, and contract tests, not the service implementation. The service is not open source. Answers can take up to a minute, and all answers are in Dutch.

Fermat 360 stores data on servers in the European Union and separates data by firm. Documents and case files held in Fermat 360 are not shared through the connector. The output supports legal research and is not legal advice, so a qualified lawyer should review it before relying on an answer. The repository itself is available under the MIT License.