MCP Logic MCP Server

An MCP server for automated first-order logic reasoning using Prover9 and Mace4.

Local serverstdioPython

What is the MCP Logic MCP server?

Mcp logic mcp server connects MCP Logic to AI assistants that speak the Model Context Protocol. An MCP server for automated first-order logic reasoning using Prover9 and Mace4.

What MCP Logic does

An MCP server for automated first-order logic reasoning using Prover9 and Mace4.

Key capabilities

  • Theorem Proving — - Prove logical statements with Prover9
  • Model Finding — - Find finite models with Mace4
  • Counterexample Finding — - Show why statements don't follow
  • Syntax Validation — - Pre-validate formulas with helpful error messages
  • Categorical Reasoning — - Built-in support for category theory proofs
  • Propositional Contingency — - Purely analytical HCC prover for fast propositional checks
  • Abductive Reasoning — - Rank hypotheses using Variational Free Energy (VFE)
  • Self-Contained — - All dependencies install automatically

Tools it exposes

Once connected, the assistant can call these 9 tools directly:

  • prove — Prove statements using Prover9
  • check-well-formed — Validate formula syntax with detailed errors
  • find_model — Find finite models satisfying premises
  • find_counterexample — Find counterexamples showing statements don't follow
  • verify_commutativity — Generate FOL for categorical diagram commutativity
  • get_category_axioms — Get axioms for category/functor/group/monoid
  • check_contingency — Check truth-functional contingency via HCC prover
  • abductive_explain — Find the VFE-minimizing explanation for an observation
  • Installation — The Installation tool exposed by this server

Installing the mcp logic mcp server

Setup follows the standard MCP pattern: clone or install the server, then register it in your client's configuration file and restart the client. The configuration snippets on this page cover Claude Desktop, Claude Code and Cursor.

Where it fits

Developer-tool servers are usually the first ones people connect, because they turn "help me with this code" into an assistant that can actually read the repo and act on it. MCP Logic sits in that group, and the shape of its toolset — prove, check-well-formed, find_model among others — tells you what it is really for. Worth comparing against the other developer tools servers in this directory before you commit to one, since several overlap in scope but differ sharply in setup cost and permissions.

Practical notes

  • This server runs locally, so it operates with whatever access your machine and its credentials already have. Scope that deliberately rather than by default.
  • With 9 tools exposed, expect a noticeable bump in prompt size — disable it in projects that never use MCP Logic.
  • Maintained by angrysky56, written in Python.
  • MCP clients ask for confirmation before each tool call by default. Keep that on while you learn what the mcp logic mcp server actually does with your data.
  • Every entry in this directory is reviewed by hand before it goes live, and details are checked against the project's own documentation.

Available tools

ToolWhat it does
proveProve statements using Prover9
check-well-formedValidate formula syntax with detailed errors
find_modelFind finite models satisfying premises
find_counterexampleFind counterexamples showing statements don't follow
verify_commutativityGenerate FOL for categorical diagram commutativity
get_category_axiomsGet axioms for category/functor/group/monoid
check_contingencyCheck truth-functional contingency via HCC prover
abductive_explainFind the VFE-minimizing explanation for an observation
InstallationThe Installation tool exposed by this server.

How to install the MCP Logic MCP server

{
  "mcpServers": {
    "mcp-logic": {
      "command": "uv",
      "args": [
        "--directory",
        "/absolute/path/to/mcp-logic",
        "run",
        "python",
        "-m",
        "mcp_logic",
        "--prover-path",
        "/absolute/path/to/mcp-logic/ladr/bin"
      ]
    }
  }
}

Configuration as documented by the project. Restart the client after saving.

Example prompts to try

  • Use MCP Logic to prove.
  • Use MCP Logic to check-well-formed.
  • Use MCP Logic to find model.

Frequently asked questions

It connects MCP Logic to MCP-compatible AI assistants such as Claude and Cursor, exposing 9 tools (prove, check-well-formed, find_model, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with MCP Logic directly.