MCP server

Connect an AI client to the Klaracase MCP server (v0.93.0) to ground answers on the corpus and citation graph.

Client support

The server offers two ways in: a personal bearer token for clients that allow custom headers, and OAuth 2.1 for chat clients that do not. Vendor details as of 2026-07-28.

Claude Code

Works todayAny plan. Add the server with the CLI or a project-scoped .mcp.json.

Cursor

Works todayAny plan. Add the server to ~/.cursor/mcp.json.

VS Code / Windsurf

Works todayAny plan. Both support custom headers on remote MCP servers.

Claude Desktop

Works todayWorks through the mcp-remote bridge, which needs Node.js installed. The built-in connector flow does not.

ChatGPT (developer mode)

Via OAuth – in trialDeveloper mode is available on the web for Plus, Pro, Business, Enterprise and Edu. Custom connectors accept OAuth only: enter the server URL. No client ID or secret is needed.

Claude (custom connector)

Works today – via OAuthCustom connectors are available on Free, Pro, Max, Team and Enterprise. The form takes the server URL; leave the OAuth credential fields empty and the client registers itself.

OAuth 2.1 has been live since 2026-07-29. We tested the Claude connector through to a first tool call with a real account the same day. The equivalent check for ChatGPT is still outstanding, which is why it reads “in trial”. Plan and authentication details were checked on 2026-07-28 and can change at any time.

Get a token

Create an API token

For clients that allow a custom Authorization header. Create and revoke your tokens in account settings. A token is shown once. Keep it like a password. If you connect via OAuth you need no token.

Open API tokens in settings

You need to be signed in to open this page. Calls are charged to your organisation's credit balance.

Connect a client

The MCP endpoint is https://klaracase.de/mcp (streamable HTTP, POST). It accepts both a bearer token and OAuth 2.1.

Connect a chat client without a token (OAuth)

For ChatGPT and Claude. No terminal and no token required: use the server address https://klaracase.de/mcp.

Add a custom connector in the client and paste the server address. Leave client ID and secret empty.
Sign in to Klaracase, then approve access on the next page.
After you approve, the client takes you back and lists the Klaracase tools.

Calls made this way are charged to your organisation's credit balance, exactly like calls made with a token.

Note: The first attempt sometimes fails: after you approve, the browser shows an error page from the chat provider and the connector stays disconnected. That happens on the provider's redirect back, not at Klaracase. Your sign-in and approval already reached us. Add the connector again. If that does not help, try a browser window without extensions (a private window). Password managers and similar extensions occasionally interfere with the redirect.

Claude Code (CLI)

Add the server with a custom Authorization header.

claude mcp add --transport http klaracase https://klaracase.de/mcp \
  --header "Authorization: Bearer YOUR_TOKEN_HERE"

Claude Code (.mcp.json)

Or commit a project-scoped .mcp.json to your repo root.

{
  "mcpServers": {
    "klaracase": {
      "type": "http",
      "url": "https://klaracase.de/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_TOKEN_HERE"
      }
    }
  }
}

Cursor

Add to ~/.cursor/mcp.json.

{
  "mcpServers": {
    "klaracase": {
      "url": "https://klaracase.de/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_TOKEN_HERE"
      }
    }
  }
}

mcp-remote (stdio bridge)

For clients that only speak stdio (e.g. Claude Desktop), bridge to the remote server with mcp-remote.

{
  "mcpServers": {
    "klaracase": {
      "command": "npx",
      "args": [
        "mcp-remote",
        "https://klaracase.de/mcp",
        "--header",
        "Authorization: Bearer YOUR_TOKEN_HERE"
      ]
    }
  }
}

A connection is working once the client lists the Klaracase tools and a first call returns a result. A client that shows the server as connected but lists no tools has not authenticated. See below.

When it does not work

After approving, the chat provider shows an error page and the connector is not connectedAdd the connector again — the second attempt almost always works. The break happens after our part: sign-in and approval already completed, only the redirect back to the chat provider failed, so it never collected the access it was granted. If it persists, open the chat provider in a private window with no extensions. Nothing is charged and no half-connected access is left behind.

The client cannot connect, or shows the server as connected but lists no toolsThe token is missing, mistyped or revoked. Check that the Authorization header reads "Bearer " followed by the whole token, including the part before the "|". Create a fresh token in settings if in doubt.

A call returns an error message instead of resultsFailures are reported as errors, never as an empty result. So an error means something went wrong on our side, not that nothing was found. Retry once; if it persists, send us the wording of the message.

The answer says there are not enough creditsThe call was not performed and nothing was charged. The message names the cost and your balance. A paid plan's allotment renews monthly, the one-time credits of Free do not. Usage is visible in the app.

The client gives up before an answer arrivesA long search can exceed a chat client's own timeout. Ask again more narrowly, with a court or a date range, so there is less to retrieve.

There is no option to add a custom connectorYour plan or client does not offer custom MCP connectors. Check the table above and use one of the supported clients.

Corpus coverage

The corpus holds German federal court decisions and statutes as well as EU instruments. It is not complete, and coverage differs by court and by year. A Fundstelle we cannot resolve is a statement about our coverage, not a judgement about the citation.

See what the Bestand holds

MCP tools

Each tool description below states its purpose, its arguments, the refusal codes it can answer and its credit price. The field-by-field meaning of every response field lives in the tool guide, so a client does not pay for it on every connection.

Read the MCP tool guide