MCP Overview

What MCP Is

The Model Context Protocol is an open standard for connecting AI clients to external tools and data. An MCP server advertises a set of tools (callable functions) and resources (read-only data) to any compliant client. The client handles authentication, tool discovery, and human review; the server handles the business logic.

What the Lev MCP Server Does

The Lev MCP server is a thin, opinionated translation layer on top of the Lev External API v2:

• It authenticates users through Auth0, not through static API keys. Each user sees the data their Lev account permits.
• It exposes 27 tools at launch covering deals, contacts, companies, lenders, placements, pipelines, term sheets, market data, and account context. Three additional lender-discovery tools are documented and in the works.
• It returns JSON strings tuned for LLM consumption — list tools wrap results with total, showing, and has_more; detail tools return a single resource.
• It translates errors into human-readable strings so models can surface the cause to the user without parsing HTTP envelopes.

It is not a replacement for the REST API. Every tool ultimately calls /api/external/v2/* on lev-backend.

Architecture

MCP Client (Claude, Cursor, …)
        │  Streamable HTTP (POST /mcp)
        ▼
Lev MCP Server (FastMCP, Python)
  ├── Auth0 JWT verification (RS256, JWKS)
  ├── Tool registry (27 live + 3 coming soon across 9 domains)
  └── Async API client (retries, circuit breaker)
        │  Authorization: Bearer <jwt>
        │  X-Origin-App: mcp
        ▼
Lev External API v2

• Transport. Streamable HTTP. No stdio, no SSE — one persistent connection per session.
• Runtime. Python, FastMCP, gunicorn + uvicorn workers in production.
• Reliability. A circuit breaker trips after 5 consecutive 5xx responses with a 30-second cooldown. 429s do not trip the breaker — rate limits are expected, not outages.
• Observability. Every tool call forwards an X-Request-Id to lev-backend. A GET /health endpoint reports version, upstream API reachability, and circuit-breaker state.

When to Use MCP

What's in the Box

• Deals — search, read, create, update, delete, and move through pipelines.
• Lender workflows — direct lender lookup today; directory search, AI lender matching, and ranked-result retrieval are coming soon.
• CRM — contacts and companies with full CRUD.
• Placements and term sheets — track outreach progression and read lender quotes.
• Market data — current SOFR, Prime, Treasury rates; asset type classifications.
• Account — profile, available accounts, team members, and live account switching.

For the full catalog with parameters and return shapes, see MCP Tools.

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