Swiss Case Law — MCP Setup Guide

Search 1,050,000+ published Swiss decisions directly inside Claude, ChatGPT, or Gemini.

There are two options: remote (no download, instant access) or local (offline access, 65 GB disk). The hosted deployment exposes the tool surface available on that server; local installs can expose additional local-update tools.

Option A: Remote server (recommended)

Connect to the hosted server. No data download, no Python, no 65 GB disk usage.

Claude Desktop / claude.ai

Plan required: Pro, Max, Team, or Enterprise.

Open Settings → Connectors
Click "Add custom connector"
Paste https://mcp.opencaselaw.ch
Click Add

Same steps in the browser (claude.ai) and the desktop app. No Node.js, no config files.

Claude Code

Any plan. One command:

claude mcp add swiss-caselaw --transport sse https://mcp.opencaselaw.ch

ChatGPT

Custom remote MCP servers connect through ChatGPT's Developer mode (full MCP connector support, currently in beta). This exposes opencaselaw's full tool surface (search_decisions, get_decision, get_law, …) in a normal chat.

Plan required: Plus, Pro, Business, Enterprise, or Education (web only). On Enterprise/Education an admin/owner must turn Developer mode on for the workspace first.

One-time setup:

Open Settings → Apps & Connectors → Advanced settings → enable Developer mode
Back on Apps & Connectors, click Create (next to Advanced settings)
Enter name: Swiss Caselaw
Paste MCP server URL: https://mcp.opencaselaw.ch
Set authentication to No authentication → click Create

The new connector appears under Drafts; open it to see the tools pulled from the server, and use Refresh there if the tool list ever changes.

To use in a chat: click the + button → Developer mode → select Swiss Caselaw. ChatGPT shows a confirmation prompt before any write action — opencaselaw is read-only, so all of its tools are safe to allow.

Which ChatGPT models can use it: custom connectors work with the Instant and Thinking models (incl. Thinking High / "extended"). They do not work with Pro models — OpenAI does not pass custom connectors/actions to the Pro models (or the o-series). So if the connector "disappears" or is never called, check the model picker: switch from Pro to Thinking for heavy reasoning over Swiss law with the connector attached. This is an OpenAI platform limitation, not an opencaselaw one.

Transport: ChatGPT supports both SSE and Streamable HTTP; the URL above serves SSE and connects directly. No API key — the server is public.

ChatGPT Deep Research is supported. The server exposes the two read-only tools deep research requires — search (query → ranked {id, title, url} results) and fetch (id → full decision text) — alongside the richer search_decisions / get_decision that regular chats use. Add the connector the same way (Developer mode, above), then select it as a source in a Deep Research prompt. (Deep research only calls search/fetch; in a normal chat ChatGPT uses the full tool set.)

Gemini CLI

Free, no account plan required.

Add to ~/.gemini/settings.json:

{
  "mcpServers": {
    "swiss-caselaw": {
      "url": "https://mcp.opencaselaw.ch"
    }
  }
}

Restart Gemini CLI after saving.

Google ADK (Agent Development Kit)

Build a Gemini-powered agent against the hosted MCP server:

pip install google-adk mcp

from google.adk.agents import LlmAgent
from google.adk.tools import MCPToolset
from mcp.client.sse import SseConnectionParams

agent = LlmAgent(
    model="gemini-3.1-pro",
    name="swiss_law_agent",
    instruction="You are a Swiss legal research assistant.",
    tools=[
        MCPToolset(
            connection_params=SseConnectionParams(
                url="https://mcp.opencaselaw.ch/sse",
            ),
        ),
    ],
)

The agent auto-discovers the tools exposed by that deployment (search_decisions, find_citations, get_law, etc.) and can call them during conversations. See the ADK MCP docs for authentication options and advanced configuration.

Google Gen AI SDK

Use MCP tools directly with the Gemini API without the full ADK framework:

pip install google-genai mcp

from google import genai
from google.genai import types
from mcp.client.sse import SseClientTransport

client = genai.Client()
tools = types.Tool(mcp_tool=types.McpTool(
    server=types.McpToolServer(
        url="https://mcp.opencaselaw.ch/sse",
    ),
))

response = client.models.generate_content(
    model="gemini-3.1-pro",
    contents="What are the leading cases on Art. 8 EMRK?",
    config=types.GenerateContentConfig(tools=[tools]),
)

The SDK handles tool discovery and execution automatically. See the Gen AI SDK docs for details.

Other MCP clients

The server uses the SSE (Server-Sent Events) transport at https://mcp.opencaselaw.ch. Any MCP client that supports remote SSE servers can connect using this URL. No authentication required.

Verify it works

After connecting, try asking:

Search for BGer decisions on Mietrecht Kündigung from 2024

You should see search results with matched decisions, snippets, and metadata.

The update_database and check_update_status tools are not available on the remote server — the dataset is updated automatically every night.

Alternative: manual JSON config for Claude Desktop (if custom connectors aren't available on your plan)

Requires Node.js 18+.

Add to your claude_desktop_config.json:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "swiss-caselaw": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://mcp.opencaselaw.ch"]
    }
  }
}

Restart Claude Desktop after saving.

Works with the Claude for Legal plugin

Anthropic's Claude for Legal plugin (contract review, NDA triage, compliance checks, briefs) reads your organisation's positions from a file called legal.local.md. Its defaults are US positions. A Swiss version is at opencaselaw.ch/claude/legal.local.md: Swiss governing law and forum, the OR liability floor, the DSG instead of GDPR-only terms, mandate law on termination, statutory written form for e-signatures, and one standing rule that every article is verified through the OpenCaseLaw connector before it is stated.

Connect the OpenCaseLaw server as above.
Install the legal plugin (Cowork: from claude.com/plugins; Claude Code: claude plugin marketplace add anthropics/knowledge-work-plugins then claude plugin install legal@knowledge-work-plugins).
Save the Swiss playbook where the plugin looks for it: .claude/legal.local.md in your project for Claude Code, or any folder you share with Cowork.

mkdir -p .claude && curl -fsSL https://opencaselaw.ch/claude/legal.local.md -o .claude/legal.local.md

Values in [brackets] are yours to set (canton of seat, liability cap, notice periods). The statute references were retrieved from the Fedlex mirror on the date stated in the file; the plugin re-verifies them through get_law when it uses them. The file is not legal advice.

A companion plugin, opencaselaw, bundles the server with skills for research, statute lookup and citation verification; it is in preparation.

Option B: Local server (offline access)

Run the MCP server locally with your own copy of the database. Requires 65 GB free disk and a one-time 30–60 minute setup.

What you need

Claude Desktop — claude.ai/download
Python 3.10 or newer — python3 --version (macOS/Linux) or python --version (Windows)
Git — git --version
65 GB of free disk space

macOS Setup

Step 1 — Download the code

Open Terminal (press Cmd + Space, type "Terminal", press Enter). Then run:

cd ~
git clone https://github.com/jonashertner/opencaselaw.git

This creates a folder at /Users/YOUR_USERNAME/caselaw-repo-1.

Step 2 — Install Python dependencies

Still in Terminal, run these three commands one by one:

cd ~/caselaw-repo-1
python3 -m venv .venv
.venv/bin/pip install mcp pydantic huggingface-hub pyarrow

Wait for the installation to finish. You should see "Successfully installed ..." at the end.

Step 3 — Find your exact paths

Run this command. It prints the two paths you'll need in the next step:

echo "command: $(cd ~/caselaw-repo-1 && pwd)/.venv/bin/python3"
echo "    arg: $(cd ~/caselaw-repo-1 && pwd)/mcp_server.py"

It will print something like:

command: /Users/anna/caselaw-repo-1/.venv/bin/python3
    arg: /Users/anna/caselaw-repo-1/mcp_server.py

Keep these — you'll paste them into the config file next.

Step 4 — Add the MCP server to Claude Desktop

You have two options. Option A uses the Claude Desktop settings UI. Option B edits the config file directly — use this if Option A doesn't work or if your version of Claude Desktop doesn't have the settings UI.

Option A: Through the Claude Desktop settings (easiest)

Open Claude Desktop
Open Settings:
- Click the Claude menu in the menu bar (top-left) → Settings...
- Or press Cmd + ,
Click Developer in the left sidebar
Click Edit Config. This opens claude_desktop_config.json in your default text editor.
Replace the entire file contents with the following. Use the paths from Step 3:

{
  "mcpServers": {
    "swiss-caselaw": {
      "command": "/Users/YOUR_USERNAME/caselaw-repo-1/.venv/bin/python3",
      "args": ["/Users/YOUR_USERNAME/caselaw-repo-1/mcp_server.py"]
    }
  }
}

Save the file (Cmd + S) and close the text editor.
Go back to Claude Desktop Settings → Developer. You should now see swiss-caselaw listed under MCP Servers.

Already have other MCP servers? Don't overwrite the file. Add the "swiss-caselaw": { ... } block inside your existing "mcpServers" object, separated by a comma.

Option B: Edit the config file manually (fallback)

If you can't find the Developer settings, edit the config file directly:

open -a TextEdit ~/Library/Application\ Support/Claude/claude_desktop_config.json

If the file doesn't exist, create it first:

mkdir -p ~/Library/Application\ Support/Claude
echo '{}' > ~/Library/Application\ Support/Claude/claude_desktop_config.json
open -a TextEdit ~/Library/Application\ Support/Claude/claude_desktop_config.json

Paste the same JSON from Option A, save, and close.

Step 5 — Restart Claude Desktop

Quit Claude Desktop completely (Cmd + Q — not just close the window). Then reopen it.

How to verify it worked: Look at the text input bar at the bottom of the chat. You should see a small hammer icon on the right side. Click it — you should see tools like search_decisions and get_decision in the list.

You can also verify in Settings → Developer — the swiss-caselaw server should show a green "running" indicator.

If you don't see the hammer icon, see Troubleshooting below.

Step 6 — Build the search index (one time, ~30–60 minutes)

In Claude Desktop, send this message:

Please run the update_database tool to download the Swiss case law dataset.

Claude will start downloading ~7 GB of data from HuggingFace and building the local search index. This takes 30–60 minutes depending on your internet connection and disk speed. You can watch the progress in Claude's response.

You only need to do this once. After it finishes, searching is instant.

Windows Setup

Step 1 — Download the code

Open PowerShell (press Win + X, select "Terminal" or "PowerShell"). Then run:

cd $HOME
git clone https://github.com/jonashertner/opencaselaw.git

This creates a folder at C:\Users\YOUR_USERNAME\caselaw-repo-1.

Step 2 — Install Python dependencies

Still in PowerShell, run these three commands one by one:

cd $HOME\caselaw-repo-1
python -m venv .venv
.venv\Scripts\pip install mcp pydantic huggingface-hub pyarrow

Wait for the installation to finish. You should see "Successfully installed ..." at the end.

Step 3 — Find your exact paths

Run this command to print the paths you need:

Write-Host "command: $HOME\caselaw-repo-1\.venv\Scripts\python.exe"
Write-Host "    arg: $HOME\caselaw-repo-1\mcp_server.py"

It will print something like:

command: C:\Users\Anna\caselaw-repo-1\.venv\Scripts\python.exe
    arg: C:\Users\Anna\caselaw-repo-1\mcp_server.py

Keep these paths for the next step. Important: when you put them in the JSON config file, you must double every backslash (\ becomes \\).

Step 4 — Add the MCP server to Claude Desktop

Option A: Through the Claude Desktop settings (easiest)

Open Claude Desktop
Open Settings:
- Click the hamburger menu (three lines, top-left) → Settings...
- Or click File → Settings...
Click Developer in the left sidebar
Click Edit Config. This opens claude_desktop_config.json in Notepad.
Replace the entire file contents with the following. Use the paths from Step 3, with doubled backslashes:

{
  "mcpServers": {
    "swiss-caselaw": {
      "command": "C:\\Users\\YOUR_USERNAME\\caselaw-repo-1\\.venv\\Scripts\\python.exe",
      "args": ["C:\\Users\\YOUR_USERNAME\\caselaw-repo-1\\mcp_server.py"]
    }
  }
}

Save the file (Ctrl + S) and close Notepad.
Go back to Claude Desktop Settings → Developer. You should now see swiss-caselaw listed under MCP Servers.

Already have other MCP servers? Don't overwrite the file. Add the "swiss-caselaw": { ... } block inside your existing "mcpServers" object, separated by a comma.

Option B: Edit the config file manually (fallback)

If you can't find the Developer settings, edit the config file directly:

notepad "$env:APPDATA\Claude\claude_desktop_config.json"

If Notepad asks whether to create the file, click Yes. Paste the same JSON from Option A, save, and close.

Step 5 — Restart Claude Desktop

Quit Claude Desktop completely (right-click the system tray icon and choose "Quit"). Then reopen it.

You can also verify in Settings → Developer — the swiss-caselaw server should show a green "running" indicator.

If you don't see the hammer icon, see Troubleshooting below.

Step 6 — Build the search index (one time, ~30–60 minutes)

In Claude Desktop, send this message:

Please run the update_database tool to download the Swiss case law dataset.

You only need to do this once. After it finishes, searching is instant.

Using it

Once connected, just ask questions in natural language. Examples:

What you type	What happens
"Find BGer decisions about Mietrecht from 2024"	Searches all Federal Supreme Court decisions on tenancy law
"Search for BVGer asylum cases involving Eritrea"	Searches Federal Administrative Court asylum decisions
"Look up BGE 133 I 106"	Fetches that specific leading case with full text
"Find decisions citing Art. 8 BV"	Searches for decisions that reference this constitutional article
"How many decisions does each court have?"	Shows statistics across all 89 courts
"Draft a legal analysis of whether X constitutes Y"	Builds a research outline grounded in actual case law
"Get a case brief for BGE 133 III 121"	Structured brief: Sachverhalt, key Erwägungen, statutes, authority, related cases
"Explain the doctrine of Art. 41 OR"	Statute text + authority-ranked BGEs + doctrine timeline
"Generate an exam question on Haftpflichtrecht"	Real BGE fact pattern with hidden analysis for Fallbearbeitung practice

The AI automatically picks the right search tool, runs the query, and shows you the results. You can then ask follow-up questions like "Show me the full text of the second result" or "Find more recent decisions on the same topic."

Studying Swiss law

Three tools power legal study and exam prep. No curriculum browsing needed — Claude builds the full session dynamically from real decisions.

Unpack a decision:

"Get a case brief for BGE 133 III 121" "Walk me through the key Erwägungen of BGE 120 II 331"

Returns the Sachverhalt, key Erwägungen (numbered), statutes with article text, citation authority, and related cases. Claude can then generate Socratic questions, hypotheticals, or a reading guide on top of this.

Explore doctrine:

"Explain the doctrine of Art. 41 OR" "What are the leading cases on Art. 8 EMRK?" "How has Tierhalterhaftung evolved in BGer case law?"

Returns statute text (if applicable), the most-cited BGEs ranked by authority, and a doctrine timeline showing how the rule developed year by year.

Practice with exam questions:

"Generate an exam question on Haftpflichtrecht" "Give me a Fallbearbeitung on Vertragsrecht"

Returns a real BGE fact pattern adapted as a Fallbearbeitung scenario. The applicable statutes, legal test, and correct outcome are hidden — ask Claude to reveal the analysis after you've worked through it.

Covered areas (100 canonical BGEs): Vertragsrecht · Haftpflicht · Sachenrecht · Familienrecht · Arbeitsrecht · Mietrecht · Strafrecht AT · Strafrecht BT · Grundrechte · Erbrecht · Gesellschaftsrecht · Zivilprozessrecht · Strafprozessrecht · Öffentliches Prozessrecht

Available tools

Tool	What it does
`search_decisions`	Full-text search with filters (court, canton, language, date range)
`get_decision`	Fetch one decision by docket number (e.g., `6B_1234/2025`) or ID
`list_courts`	List all 89 courts with decision counts and date ranges
`get_statistics`	Aggregate statistics by court, canton, or year
`find_citations`	Show what a decision cites and what cites it
`find_appeal_chain`	Trace the appeal chain (Instanzenzug) across court levels
`find_leading_cases`	Find the most-cited decisions for a topic or statute
`analyze_legal_trend`	Year-by-year decision counts for a statute or topic
`draft_mock_decision`	Legal research outline grounded in case law and statutes
`get_case_brief`	Structured case brief: Sachverhalt, key Erwägungen, statutes, authority, related cases
`get_doctrine`	Statute text + authority-ranked BGEs + doctrine timeline for any statute or concept
`generate_exam_question`	Real BGE fact pattern as Fallbearbeitung exercise with hidden analysis
`get_law`	Look up a Swiss federal law by SR number or abbreviation
`search_laws`	Full-text search across Swiss federal law articles
`search_legislation`	Search 30,000+ Swiss legislative texts (federal + all 26 cantons) via LexFind.ch
`get_legislation`	Get details for a specific law by LexFind ID or SR number
`browse_legislation_changes`	Browse recent legislation changes for a canton or federal level
`update_database`	Download the latest data from HuggingFace (local only)
`check_update_status`	Check progress of a running database update (local only)

Keeping the dataset up to date

Remote server: The dataset is updated automatically every night. No action needed.

Local server: Ask your AI to run the update_database tool:

Update the Swiss case law database.

This downloads only the changed files and updates the index. Much faster than the initial build.

Some deployments may also use the HuggingFace artifacts/manifest.json file when it advertises a full SQLite snapshot under snapshot.sqlite_zst. That snapshot is a bootstrap artifact for external tools; the current local MCP update_database tool still uses the Parquet download/rebuild path.

For a manual snapshot bootstrap recipe, see the "SQLite snapshot artifacts" section in the repository README.

Troubleshooting

No hammer icon after restarting Claude Desktop

This means Claude Desktop didn't load the MCP server. Check these in order:

Is the config file in the right place?
- macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
- Windows: %APPDATA%\Claude\claude_desktop_config.json
Is the JSON valid? Open the file and check for:
- Missing or extra commas
- Mismatched braces { }
- Unescaped backslashes on Windows (must be \\, not \)
Do the paths actually exist? Test by running the command directly in your terminal:
```
/Users/YOUR_USERNAME/caselaw-repo-1/.venv/bin/python3 --version
```
This should print Python 3.x.x. If it says "No such file", the path is wrong.
Did you fully quit Claude Desktop? On macOS, use Cmd + Q. Just closing the window is not enough.

"Database not found" or empty results

You need to build the search index first. Ask Claude to run the update_database tool (Step 6 above).

First search is slow

The first query after opening Claude Desktop takes 3–5 seconds to load the ~58 GB database into memory. Every subsequent search is fast.

"Permission denied" errors on macOS

If your terminal says "permission denied" when running Python:

chmod +x ~/caselaw-repo-1/.venv/bin/python3

Python not found

macOS: Install Python from python.org or via Homebrew: brew install python
Windows: Install Python from python.org. During installation, check "Add Python to PATH".

Not enough disk space

The full search index requires ~65 GB. If you don't have enough space, the update_database tool will fail partway through. Free up space and run it again — it resumes where it left off.

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Swiss Case Law — MCP Setup Guide

Option A: Remote server (recommended)

Claude Desktop / claude.ai

Claude Code

ChatGPT

Gemini CLI

Google ADK (Agent Development Kit)

Google Gen AI SDK

Other MCP clients

Verify it works

Works with the Claude for Legal plugin

Option B: Local server (offline access)

What you need

macOS Setup

Step 1 — Download the code

Step 2 — Install Python dependencies

Step 3 — Find your exact paths

Step 4 — Add the MCP server to Claude Desktop

Option A: Through the Claude Desktop settings (easiest)

Option B: Edit the config file manually (fallback)

Step 5 — Restart Claude Desktop

Step 6 — Build the search index (one time, ~30–60 minutes)

Windows Setup

Step 1 — Download the code

Step 2 — Install Python dependencies

Step 3 — Find your exact paths

Step 4 — Add the MCP server to Claude Desktop

Option A: Through the Claude Desktop settings (easiest)

Option B: Edit the config file manually (fallback)

Step 5 — Restart Claude Desktop

Step 6 — Build the search index (one time, ~30–60 minutes)

Using it

Studying Swiss law

Available tools

Keeping the dataset up to date

Troubleshooting

No hammer icon after restarting Claude Desktop

"Database not found" or empty results

First search is slow

"Permission denied" errors on macOS

Python not found

Not enough disk space