JSON Contracts MCP Server: Install & Setup

Install JSON Contracts in Claude Code

Claude Code

claude mcp add json-contracts -- npx -y json-contracts

mcp.json (Claude Desktop, Cursor, VS Code, Windsurf)

{
  "mcpServers": {
    "json-contracts": {
      "command": "npx",
      "args": [
        "-y",
        "json-contracts"
      ]
    }
  }
}

JSON contract registry and validator for structured LLM and agent outputs.

Yes, most likely. Open source and no paid account or API key is mentioned in the listing. Check the provider for current pricing.

Local. Runs on your machine (stdio). You install it with npx, uvx, Docker or from source.

Run: claude mcp add json-contracts -- npx -y json-contracts

trycua/cua

MCP server for the Computer-Use Agent (CUA), allowing you to run CUA through Claude Desktop or other MCP clients.

oraios/serena

Coding agent that uses language servers for symbolic code operations.

mastra-ai/mastra

Client implementation for Mastra, providing seamless integration with MCP-compatible AI models and tools.

wonderwhy-er/DesktopCommanderMCP

Manage and execute programs, and read, write, search and edit code and text files.

Q00/ouroboros

Local agent OS for spec-first AI coding: a replayable, ledger-recorded interview, seed, execute, evaluate and evolve loop that MCP clients can drive.

lingodotdev/lingo.dev

Make your AI agent speak every language on the planet, using Lingo.dev Localization Engine.