AISchemaGate and DataContractGate

Name: AISchemaGate and DataContractGate
Author: nightmoose

by nightmooseversion 0.4.1i★ 4iRuns on your computer

Registry nameio.github.nightmoose/contractgate

Install

Overview

Description from the maker (original English)

AISchemaGate validates and repairs structured LLM output against a contract, plus DataContractGate.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi2 of 2 passedChecked from public information; code not scanned yet
UsageiEarly↓ 123/wk · ★ 4

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Search & AI memory
You need to fill in: CONTRACTGATE_API_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 2 of 2 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: CONTRACTGATE_API_KEY, CONTRACTGATE_BASE_URL

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "contractgate": {
      "command": "npx",
      "args": [
        "-y",
        "@nightmoose/contractgate-mcp-server"
      ],
      "env": {
        "CONTRACTGATE_API_KEY": "your-value",
        "CONTRACTGATE_BASE_URL": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add contractgate --env CONTRACTGATE_API_KEY=your-value --env CONTRACTGATE_BASE_URL=your-value -- npx -y @nightmoose/contractgate-mcp-server

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "contractgate": {
      "command": "npx",
      "args": [
        "-y",
        "@nightmoose/contractgate-mcp-server"
      ],
      "env": {
        "CONTRACTGATE_API_KEY": "your-value",
        "CONTRACTGATE_BASE_URL": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "contractgate": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@nightmoose/contractgate-mcp-server"
      ],
      "env": {
        "CONTRACTGATE_API_KEY": "your-value",
        "CONTRACTGATE_BASE_URL": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

CONTRACTGATE_API_KEY secret required env
DataContractGate API key (cg_live_...). Create one at https://app.datacontractgate.com/account
CONTRACTGATE_BASE_URL env
Gateway base URL. Defaults to https://api.datacontractgate.com

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

Which apps can use it

Based on how this server connects and on each app’s own docs, checked Nov 10, 2026.

Run on your computer in

Claude Goose LM Studio Msty Studio Cherry Studio Cursor VS Code + GitHub Copilot Visual Studio Windsurf (Devin Desktop)Zed Kiro Cline Continue JetBrains AI Assistant Claude Code Codex CLI Gemini CLI OpenCode nodecode Warp LibreChat Raycast

All apps, with pros and cons →

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 10, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account nightmoose, which owns the repo
✓ Pass
Still maintained
Code last changed yesterday
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Search & AI memoryi

More stars than 86% of the other 5857 servers in this category
Published to the registry more recently than 75% of the other 5857 servers in this category
Basic checks equal to or better than 100% of the other 5857 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is AISchemaGate and DataContractGate safe?

It passed 2 of 2 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: CONTRACTGATE_API_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed yesterday, and the latest version (0.4.1) reached the registry 13 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Ruflo, Context7, Metabase

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:↓ Downloads per weeki★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

Ruflo

Agent teams, swarms, memory and hooks for Claude Code and Codex, served over MCP.

by ruvnetWidely used↓ 74.3K/wk★ 81.4KUpdated today

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Install

Context7

Feeds AI the latest docs for libraries and frameworks before it answers, so code it writes does not use outdated, removed functions.

by upstashWidely used↓ 1.2M/wk★ 64.4KUpdated yesterday

Computer or cloud

Install

Metabase

Lets AI clients search, explore, query, and visualize data in a Metabase instance.

by metabaseWidely used★ 50.3KUpdated 6 months ago

Runs in the cloud

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

@nightmoose/contractgate-mcp-server

AISchemaGate validates and repairs structured LLM output against a contract, plus DataContractGate data contracts. Repair uses the violation fields from that check. The contract checks values a JSON Schema or Pydantic validation can leave open.

Official Model Context Protocol server. Thin stdio wrapper over the HTTP API at https://api.datacontractgate.com (override with CONTRACTGATE_BASE_URL). The dashboard host https://app.datacontractgate.com is not the gateway.

One server, two products, same API key:

AISchemaGate — validates structured LLM output (egress_validate → POST /egress/{id}). Repair uses the violation fields from that check (min, max, pattern, enum, compliance_mode). Forward payload from the tool result, not the original body.
DataContractGate — infer and deploy data contracts, validate ingest (validate_events → POST /v1/ingest/{id}), including ODCS v3.1.0 and v3.2.0 contracts, and inspect quarantine (get_quarantine). Replay stays on the HTTP API (POST /contracts/{id}/quarantine/replay).

Registry metadata for the Official MCP Registry is server.json. The title and description lead with AISchemaGate (description is the 100-character registry field). The server name stays io.github.nightmoose/contractgate. Keywords and the longer summary are under _meta. Smithery config is smithery.yaml; its default contractgateBaseUrl is the API gateway. npm keywords, this README, and DIRECTORY_LISTINGS.md are the directory listing.

See docs/mcp-reference.md for tools and auth. AISchemaGate app integrations: docs/integrations/.

"mcpServers": { "contractgate": { "command": "npx", "args": ["-y", "@nightmoose/contractgate-mcp-server"], "env": { "CONTRACTGATE_API_KEY": "${CONTRACTGATE_API_KEY}" } } } }

cd mcp

npm install npm test npm run build

AISchemaGate and DataContractGate

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

Which apps can use it

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Search & AI memoryi

Common questions

Alternatives

Ruflo

Context7

Metabase

README from the maker

@nightmoose/contractgate-mcp-server