kryptheon-mcp

kryptheon-mcp

Kryptheon inside your AI coding tool. Your assistant records a flow through your app, checks it again after every change, and attacks a copy of your database - and tells you in plain English what broke.

Works with anything that runs MCP servers: Cursor, Claude Code, Codex, Windsurf, Antigravity, VS Code.

What your assistant gets

tool	what it does
kryptheon_record	opens your app in a browser on your screen; you click through one short flow and close the window, and it is saved as a test
kryptheon_check	replays every recording and says what still works and what broke - the button that went missing, the page it was on, and a line to paste back
kryptheon_scan_database	copies the shape of your Supabase/Postgres database into a throwaway schema, attacks the copy, reports, deletes it. Never touches your rows
kryptheon_job	long runs hand back a job; this waits for the answer

The assistant is told to run kryptheon_check after every change and not to call a change done until it passes.

Set it up

You need Node.js 20.6 or later. Nothing else to install - your tool starts the server itself.

Cursor, in one click: Add Kryptheon to Cursor

• Cursor asks you to confirm, then it is there. VS Code has a one-click button on kryptheon.tech.

Claude Code

claude mcp add kryptheon -- npx -y kryptheon-mcp

Codex - ~/.codex/config.toml

[mcp_servers.kryptheon]
command = "npx"
args = ["-y", "kryptheon-mcp"]

Cursor (~/.cursor/mcp.json), Windsurf / Devin Desktop (Cascade panel, the ... menu, Open MCP config file - newer versions keep it in %APPDATA%\devin\mcp_config.json), Antigravity (~/.gemini/config/mcp_config.json - Manage MCP Servers, then View raw config), Claude Desktop (Settings, Developer, Edit Config - then quit and reopen Claude)

Step by step for each tool, with copy buttons: kryptheon.tech.

{
  "mcpServers": {
    "kryptheon": {
      "command": "npx",
      "args": ["-y", "kryptheon-mcp"]
    }
  }
}

VS Code - .vscode/mcp.json (note: servers, not mcpServers)

{
  "servers": {
    "kryptheon": {
      "command": "npx",
      "args": ["-y", "kryptheon-mcp"]
    }
  }
}

On Windows, if your tool says it cannot start npx, use this instead:

"command": "cmd",
"args": ["/c", "npx", "-y", "kryptheon-mcp"]

Then just ask: "record the sign-in flow of http://localhost:3000", or "check the app".

Scanning your database

The scan needs your database's connection string. It goes in the config, never in the chat - pasting it into a conversation puts the password to your whole database in a transcript.

"kryptheon": {
  "command": "npx",
  "args": ["-y", "kryptheon-mcp"],
  "env": { "KN_DATABASE_URL": "postgresql://..." }
}

Where to find it in Supabase: Project Settings (the gear, bottom left) -> Database -> Connection string -> URI -> Session pooler. Replace [YOUR-PASSWORD] with your database password.

An app on Lovable Cloud (Lovable's built-in backend) has no connection string to give. The scan reaches apps whose Supabase project you own.

How it works

The server is a few hundred lines with no dependencies, so the first time - nothing cached, fetched from npm - it starts in about four seconds, measured. Some tools give a server ten seconds; the official SDK alone took fifteen. The work is done by the published commands, fetched when a tool is first used: kryptheon for recording and checking, kryptheon-night for the database. Nothing is uploaded anywhere; there is no server on our side.

What has been tested, and what has not

Tested for real, on Windows 11:

• the official MCP SDK client: handshake at every protocol version from 2024-11-05 to 2025-11-25, all four tools listed and called end to end
• Claude Code: starts the server with plain npx and with cmd /c npx, connects, sees all four tools
• an address built to run a command through a shell (&md,...) reaches kryptheon as an address and runs nothing

Not yet run by hand: Cursor, Codex, Windsurf, Antigravity, VS Code. They are configured from their own documentation. If one of them does not work, that is a bug - please say so.

Licence

MIT