OLDP MCP Server

The Open Legal Data Platform exposes a Model Context Protocol (MCP) server, enabling AI agents (Claude, Cursor, etc.) to search, retrieve, and navigate German legal data including court decisions and legislation with cross-references.

Quick Start

Claude Desktop / Claude Code

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "oldp": {
      "url": "https://de.openlegaldata.io/mcp"
    }
  }
}

Claude.ai (Custom Connector)

Go to Settings → Connectors → Add Custom Connector
Enter URL: https://de.openlegaldata.io/mcp
Click Add — works immediately without login

Claude Code CLI

claude mcp add --transport http oldp https://de.openlegaldata.io/mcp

Authentication

The MCP server supports two modes:

Mode	How it works	Rate limit
Anonymous	No login required	500 requests/hour (shared for Anthropic IPs)
Authenticated	OAuth 2.0 login with OLDP account	1,000 requests/hour (per user)

OAuth Flow

The server implements OAuth 2.0 with PKCE and Dynamic Client Registration (RFC 7591). Discovery endpoints:

/.well-known/oauth-protected-resource — Resource metadata
/.well-known/oauth-authorization-server — Authorization server metadata
/oauth/register/ — Dynamic Client Registration
/oauth/authorize/ — Authorization endpoint
/oauth/token/ — Token endpoint

Available Tools

Discovery

Tool	Description
`get_platform_info`	Platform coverage summary: total cases, laws, courts, date ranges
`list_courts`	Browse/filter courts by type, state, jurisdiction, level of appeal
`list_law_books`	List available law books (BGB, StGB, GG, etc.) with section counts

Search

Tool	Description
`search_cases`	Full-text search via Elasticsearch. Returns snippets, not full text. Accepts citation-graph filters (`cited_law_book` + `cited_law_section` or `cited_case_id`) that compose with the keyword query — e.g. “cases citing § 823 BGB that mention ‘Mietrecht’”
`search_laws`	Full-text search across law sections. Returns snippets only
`filter_cases`	Structured ORM filtering by court, date, file number, ECLI, etc.

See Search for the full filter matrix and combined-search examples across all three surfaces.

Retrieval

Tool	Description
`get_case`	Full case by ID/slug. Truncated at 30k chars; use `full_text=True` for 100k
`get_law_section`	Law text by book code + section (e.g. “BGB” + “823”)
`get_court`	Detailed court info: name, address, contact, case count

Cross-References

Tool	Description	Backend
`validate_citation`	Check if Aktenzeichen, ECLI, or § reference exists in the database	SQL
`get_case_references`	Forward refs: which laws and cases does a decision cite?	SQL
`get_citing_cases`	Reverse refs: which cases cite a given decision?	Elasticsearch
`get_cases_for_law`	All cases interpreting a specific statute section	Elasticsearch

The same data is queryable via the REST API’s citation surfaces: nested actions like /api/cases/<id>/references/ for case-by-case lookups, plus a flat /api/references/ resource with slug-based filters (cited_by_law__book__slug=bgb&cited_by_law__slug=823) for cross-cutting graph queries the MCP tools can’t express. The REST nested actions and the MCP tools share a single service layer and the same backends — references / forward-refs paths via the ORM, citing_cases paths via Elasticsearch — so payload shapes match.

When Elasticsearch is unavailable, get_citing_cases and get_cases_for_law return a structured error envelope rather than silently degrading:

// Transient timeout — same query is sub-100ms after segments are
// paged in. Agent should wait + retry.
{"error": "Search timed out…", "retryable": true, "hint": "…"}

// Hard outage — retrying immediately won't help.
{"error": "Citation graph is temporarily unavailable. Try again in a few minutes.", "retryable": false}

Agents should branch on retryable rather than parsing the message. See docs/elasticsearch.md for the underlying CaseIndex.cited_laws / CaseIndex.cited_cases fields.

Statistics

Tool	Description
`get_case_statistics`	Aggregated counts by court, year, jurisdiction

Usage Examples

Legal Research

“Find BGH decisions from 2023 about § 823 BGB”

search_cases(query="§ 823 BGB", court_code="BGH", start_date="2023-01-01", end_date="2023-12-31")
get_case(case_id=12345) for full text
get_case_references(case_id=12345) for cited laws/cases

Citation Verification

“Is ‘VI ZR 123/22’ a valid BGH file number?”

validate_citation(citation="VI ZR 123/22")

Legislative Impact Analysis

“How is § 1004 BGB interpreted in case law?”

get_cases_for_law(book_code="BGB", section="1004")
get_case(case_id=...) for relevant decisions

Design Principles

Verbatim text only: No AI-generated summaries. The agent summarizes; we provide the source.
Search → Retrieve pattern: Search returns snippets; get_case/get_law_section returns full text.
Citation validation: Built-in hallucination guard for legal citations.
Content truncation: Cases truncated at 30k chars by default to protect context windows.

Disclaimer

This data is provided for informational purposes only and is not a substitute for professional legal advice. References are automatically extracted and may be incomplete. Verify critical citations against the full text.

Technical Details

Transport: Streamable HTTP at /mcp
Package: django-mcp-server v0.5.7
OAuth: django-oauth-toolkit v3.x
Search: Elasticsearch 7.17 via django-haystack