Legal Research MCP 0.3.3-dev

0.3.3-dev hardens positive BFH get_case retrieval by replaying the actual live decision-search form state using label-based semantic field discovery and preserved cookies. The target-case evidence gate remains fail-closed unless the official target decision is opened.

Legal Research MCP MVP 0.3.2-dev - Render Free

Render-ready read-only research MCP for the planned legal-tax-advisor-de v2.3.0 research layer.

What 0.3.2-dev changes

0.3.2-dev is a narrow follow-up to the positive BFH get_case retrieval patch. The structured fail-closed evidence gate introduced in 0.3.0-dev remains unchanged. After deployment of 0.3.1-dev, Render showed that the official BFH page could be retrieved without a parseable decision-search <form>, causing BFH_SEARCH_FORM_NOT_FOUND before any search submission.

• still prefers replaying the live BFH TYPO3/Extbase form state when available;

• if the search form is not parseable, uses a bounded direct-GET fallback with the official visible field names;

• tries case number + date, case number only, then quoted case number in Suchbegriff;

• opens the positive path only when an exact official result hit is found;

• never converts an unverified direct-fallback no-hit into definitive not_found;

• returns structured transport/search diagnostics while preserving the closed evidence gate on failure;

• keeps the pre-2010 closed gate and all other Legal Research tools unchanged.

Related MCP server: de-eli-mcp

Tools

search_primary_sources

Controlled discovery for a small validated legislation registry (KStG, EStG, AO, GewStG). Discovery only.

get_norm

Retrieves the current official consolidated provision from gesetze-im-internet.de and returns structure/evidence metadata.

trace_norm_amendments

Safe amendment-history connectivity implementation. It may expose a whole-statute amendment header as a discovery lead but deliberately remains partial/unknown until a provision-specific chain resolver is implemented.

get_case

Mandatory target-case retrieval/evidence gate for named BFH decisions. If data.content_gate.target_case_content_allowed=false, no facts, holding, reasons, headnotes, quotes, paraphrases, or attributed legal propositions may be stated about the target case.

See docs/case-law-evidence-gate.md.

get_official_document_text

Opens an identified official document and verifies an exact passage.

Public MCP inputs (all required strings):

• document_ref: supported official document ID or allowlisted official HTTPS URL;

• locator: targeted location such as Artikel 30 Nummer 1;

• query: exact phrase to verify such as § 8b Absatz 6 Satz 2.

Supported document-id shortcuts include:

• BR-Drs. 5/26 -> Bundesrat document server PDF;

• BT-Drs. 21/3343 -> Bundestag document server PDF;

• BGBl. 2026 I Nr. 33 -> official recht.bund.de promulgation page.

Example amendment verification target:

get_official_document_text(
  document_ref="BR-Drs. 5/26",
  locator="Artikel 30 Nummer 1",
  query="§ 8b Absatz 6 Satz 2"
)

A successful normalized query match returns coverage_status=complete and full_checked passage evidence. A locator-only result is navigation evidence and must not be treated as proof of the requested amendment phrase.

Public schema target

The Copilot-facing contract is intentionally simple:

{
  "type": "object",
  "properties": {
    "document_ref": {"type": "string"},
    "locator": {"type": "string"},
    "query": {"type": "string"}
  },
  "required": ["document_ref", "locator", "query"]
}

SSRF / download safety

get_official_document_text remains deliberately constrained:

• HTTPS only;

• exact official-host allowlist;

• every redirect hop is revalidated;

• credentials and non-standard ports are rejected;

• download size capped at 20 MB;

• PDF text extraction only, no JavaScript/browser execution;

• read-only requests only.

Current allowlisted families include the official Bundestag/Bundesrat document server, recht.bund.de, gesetze-im-internet.de, Bundestag/Bundesrat web hosts, the Federal Ministry of Finance website, and the Bundesfinanzhof website.

Render deployment

Use the included render.yaml Blueprint. The service remains configured as:

• Web Service;

• Docker runtime;

• Free plan;

• Frankfurt region;

• /health health check;

• dynamic binding to Render's PORT;

• MCP endpoint at /mcp;

• explicit Host allowlisting from RENDER_EXTERNAL_HOSTNAME.

Detailed steps: docs/render-free-deploy.md.

Local setup

python -m venv .venv
source .venv/bin/activate
pip install -r requirements-dev.txt
python -m pytest -q
uvicorn app:app --reload --port 8080

Local endpoints:

• Health: http://localhost:8080/health

• MCP: http://localhost:8080/mcp

Still not implemented

• historical statutory version resolver;

• complete provision-specific amendment-chain resolver;

• automatic discovery of every Bundesgesetzblatt/Bundestag/Bundesrat document;

• broader multi-court case-law retrieval and citation graph;

• comprehensive BMF guidance retrieval;

• production authentication.

DEV security boundary

The Render Free deployment remains intentionally unauthenticated for DEV testing. Do not publish the Copilot agent and do not send confidential client/matter facts through the endpoint.

Free Render Web Services can spin down after inactivity and are not a production target.

0.3.1 -> 0.3.2 upgrade

1. Apply the 0.3.2-dev repository update and push to the branch Render deploys.

2. Verify /health returns version 0.3.2-dev.

3. No agent-skill change is required.

4. Directly test get_case with BFH, IX R 12/22, 2023-05-03.

5. Require an open gate before resuming RC2 release testing.

6. Re-run VIII R 10/96, 1998-07-07 as the negative closed-gate control.

See UPGRADE-0.3.2-DEV.md, docs/bfh-positive-retrieval.md, and docs/case-law-evidence-gate.md.