AISchemaGate and DataContractGate runs on your own machine — the client starts it, so there is no endpoint to ping. 288 installs a week from npm. Last commit 29 Oct 2026.
AISchemaGate validates and repairs structured LLM output against a contract, plus DataContractGate.
What the code does
We read the source, 3 d ago · rules 995398eba69f
What this server is able to do. For an MCP server this is often the job itself — a terminal server runs commands because that is what it is for. Listed so you know what you are plugging in, not as an accusation.
ON CONFLICT (org_id, period) DO UPDATE
SET events = org_monthly_usage.events + EXCLUDED.events,
ARG NEXT_PUBLIC_API_KEY=""
Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.
This code can reach further than it looks
We found places where it runs commands, builds paths or queries from values it is given. None of that is a flaw by itself — it becomes one when the code changes, and code changes quietly between releases. We re-read it on every one.
Connect this server
This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.
claude mcp add contractgate -e 'CONTRACTGATE_API_KEY=<CONTRACTGATE_API_KEY>' -- npx -y @nightmoose/contractgate-mcp-server{
"mcpServers": {
"contractgate": {
"command": "npx",
"args": [
"-y",
"@nightmoose/contractgate-mcp-server"
],
"env": {
"CONTRACTGATE_API_KEY": "<CONTRACTGATE_API_KEY>"
}
}
}
}[mcp_servers.contractgate]
command = "npx"
args = ["-y", "@nightmoose/contractgate-mcp-server"]
env = { CONTRACTGATE_API_KEY = "<CONTRACTGATE_API_KEY>" }{
"mcpServers": {
"contractgate": {
"command": "npx",
"args": [
"-y",
"@nightmoose/contractgate-mcp-server"
],
"env": {
"CONTRACTGATE_API_KEY": "<CONTRACTGATE_API_KEY>"
}
}
}
}{
"servers": {
"contractgate": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@nightmoose/contractgate-mcp-server"
],
"env": {
"CONTRACTGATE_API_KEY": "<CONTRACTGATE_API_KEY>"
}
}
}
}Put your own value in place of
<CONTRACTGATE_API_KEY> (DataContractGate API key (cg_live_...). Create one at https://app.datacontractgate.com/account).
The author’s registry entry marks it as required.
Optional settings from the registry entry, left out of the block above:
CONTRACTGATE_BASE_URL (Gateway base URL. Defaults to https://api.datacontractgate.com).
Alternatives to AISchemaGate and DataContractGate
same job, measured the same wayJSON contract registry and validator for structured LLM and agent outputs.
Repair broken JSON from LLM output and validate it against a JSON Schema.
Repairs malformed JSON from LLM output, validated against a schema. Paid per call via Stripe.
Structured-output enforcer: extract and validate JSON from messy LLM text.
Zero-dependency JSON schema subset validator ensuring LLM structured outputs strictly conform to con
Validate JSON-LD structured data against the Schema.org vocabulary. Free; never fetches URLs.
Extract structured, schema-validated data from PDFs, scans, images, spreadsheets, and forms.
Validate, transform, and normalize structured data for AI agents.
AISchemaGate and DataContractGate — questions
Answers built from our own checks of this server.