Nexus Legal MCP

What djtellado/nexus-legal-mcp MCP server does

The djtellado/nexus-legal-mcp MCP server connects MCP-compatible clients to Nexus Legal. Its tools support legal analysis, document drafting, adversarial review, litigation scenario simulation, administrative doctrine research, case-law search, legislative lookup, and citation verification. The available jurisdiction codes include Spain, Great Britain, Colombia, Singapore, the United States with selected state overlays, and other options; however, selectable jurisdictions do not necessarily have the same corpus coverage.

The service is suited to workflows where an agent needs more than general legal text generation. It can compare two to fifteen jurisdictions, calculate certain procedural deadlines, inspect the relationship between provisions and judgments, compare document versions, check conflicts of interest, and analyze a Box file when an active Box connection is available.

How it works

Install the package as a local stdio MCP server. The client launches it with npx, and the server sends requests to Nexus Legal using the configured API key. Claude Desktop, Claude Code, Cursor, and other MCP-compatible clients can then discover the exposed tools.

Calls use account credits. Generative operations such as analysis, drafting, auditing, red teaming, and Monte Carlo simulation have different credit costs. Case-law and additional legislation may require jurisdiction-specific add-ons. Requests made without the relevant balance or entitlement can fail with an access error rather than returning grounded content.

Some accounts require a customer-provided LLM engine for generative endpoints. Read-only search and corpus coverage tools do not require an engine because they do not generate content. Long reasoning-model analyses may exceed the synchronous 300-second gateway limit; the documented alternative is the asynchronous jobs API, while standard mode is shorter for supported MCP calls.

Setup and configuration

Create an MCP key from the Nexus Legal developer portal and store it as NEXUS_API_KEY. The key is shown only once when created. A Claude Desktop configuration uses the npx command with -y @nexus-legal/mcp, plus the key in the server’s environment settings. Cursor uses the same command and environment variable in its MCP configuration. Claude Code can add the server with the equivalent npx command and an exported key.

After restarting the client, the Nexus tools should appear in the client interface. An account with a positive credit balance is required for calls, and premium corpus features depend on the account’s enabled jurisdiction add-ons.

Tools and capabilities

The documented tool set includes:

• Legal analysis, open-ended consultation, drafting, cross-audit, consensus, second opinions, adversarial arguments, and red-team review.
• Monte Carlo litigation simulation and strategic negotiation playbooks.
• Administrative doctrine and multi-jurisdiction case-law search.
• Deterministic citation verification, document-wide citation checking, and provision-to-judgment graph exploration.
• Procedural deadline calculation for Spain and England and Wales through the listed jurisdiction modes.
• Legislation search, historical provision text, legislative hierarchy, and corpus coverage inspection.
• Box file analysis, document version comparison, conflict checking, firm inbox review, and case-context chat.

Limitations and notes

The djtellado/nexus-legal-mcp MCP server is a paid service rather than a free local legal database. Each call requires an account and available credits, while some searches require additional content entitlements. Corpus depth, freshness, and search availability vary by jurisdiction and should be checked with the coverage tools.

The server does not establish that every selectable jurisdiction has official-source grounding. Generated legal output should therefore be evaluated against the returned certainty, citation, and audit information. Accounts configured for bring-your-own-engine use must register and enable a provider before generative tools can run; retrying the same request does not resolve that configuration error.

The package exposes tools through MCP, but the underlying Nexus Legal service remains responsible for account billing, content access, model configuration, and API processing.