Vantagate MCP Server

VantaGate MCP Server & OpenAPI Integration

Human-in-the-Loop authorization for AI Agents. VantaGate intercepts high-risk actions, routes them to a human approver via Slack or Email, and returns a cryptographically-signed decision - so your agent resumes or halts with a full audit trail.

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What is VantaGate?

AI agents are increasingly capable of executing consequential real-world actions: sending emails to thousands of users, deleting database records, moving money, deploying to production. VantaGate is the trust layer that ensures humans remain in control.

Agent hits risky action

↓ POST /v1/checkpoint ──→ Human receives Slack/Email notification ↓ ↓ id and status Human reviews payload & decides ↓ ↓ Poll GET /v1/checkpoint/{id} ←── Decision recorded + payload purged ↓ APPROVED → Resume workflow REJECTED → Halt + report reason

Key Guarantees

• < 100ms API response - your agent is never blocked waiting for I/O
• AES-256 payload encryption at rest - payload is permanently destroyed after the decision
• Zero-Retention polling - GET /checkpoint/{id} never returns the original payload
• Cryptographic audit trail - every decision is HMAC-SHA256 signed
• Stateless protocol - no SDK required; plain HTTP from any language

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This Package

This package ships two integration artifacts for connecting any AI agent to VantaGate:

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Prerequisites

• Node.js >= 20
• A VantaGate account: https://vanta-gate.com
• A VantaGate API key (Dashboard → Projects → New Project)

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Quick Start

Option A: Use the MCP Server with Claude Desktop

The fastest path. No manual setup required.

Step 1: Get your API key from https://vanta-gate.com/dashboard/projects

Step 2: Add VantaGate to your Claude Desktop config.

Open your claude_desktop_config.json:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

{

"mcpServers": { "vantagate": { "command": "npx", "args": ["-y", "@vantagate/mcp-server"], "env": { "VANTA_API_KEY": "YOUR_API_KEY_HERE" } } } }

Step 3: Restart Claude Desktop. The tools create_vantagate_checkpoint and check_vantagate_status will appear in Claude's tool list.

Step 4: Ask Claude to do something that requires approval:

*"Delete all records from the staging database where created_at < 2024-01-01"*

Claude will automatically pause, create a checkpoint, and tell you to check your email or Slack for the approval notification.

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Option B: Use the OpenAPI Spec (No-Code / Low-Code)

Import vanta-gate-openapi.json directly into your tool of choice.

OpenAI GPTs / Custom Actions

1. Open your GPT editor at https://platform.openai.com/gpts
2. Click "Add actions" → "Import from URL" or paste the JSON
3. Set Authentication → API Key → Header: X-API-KEY
4. Enter your VantaGate API key

The GPT will now pause before high-risk tool calls and ask for human approval.

Alice (AI Agent Platform)

1. Go to Integrations → Import OpenAPI
2. Upload or paste vanta-gate-openapi.json
3. Set header X-API-KEY to your VantaGate API key in the credential store
4. Map create_vantagate_checkpoint to your agent's "before high-risk action" trigger

n8n / Zapier

1. Add an HTTP Request node
2. Import the OpenAPI spec to auto-populate endpoints
3. Set X-API-KEY header in the credential configuration

LangChain / LlamaIndex

from langchain.tools import OpenAPITool

vanta_tool = OpenAPITool.from_openapi_spec( spec_path="./vanta-gate-openapi.json", headers={"X-API-KEY": os.environ["VANTA_API_KEY"]} ) agent = initialize_agent([vanta_tool], llm, agent=AgentType.OPENAI_FUNCTIONS)

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Available MCP Tools

create_vantagate_checkpoint

Pauses the agent workflow and routes a human approval request.

When Claude uses it: Before any high-risk action - financial operations, data deletion, production deployments, bulk communications.

Returns: checkpoint_id and step-by-step instructions for the agent.

check_vantagate_status

Polls the decision status of a pending checkpoint.

Returns: status (PENDING / APPROVED / REJECTED / RESOLVED / EXPIRED), selected_option, reject_reason, and the full audit trail.

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API Reference Summary

Base URL: https://api.vanta-gate.com/v1 Authentication: X-API-KEY header

Checkpoint Status Lifecycle

PENDING → APPROVED   (human chose first/positive option)

→ REJECTED (human rejected with optional reason) → RESOLVED (human chose non-primary option) → EXPIRED (timeout elapsed, no decision)

Error Codes

All errors follow the envelope:

{

"statusCode": 400, "error": "Machine_Readable_Code", "message": "Human-readable description." }

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Subscription Tiers

Timeout values are silently clamped to your plan's maximum. A Free plan request with timeout: "7d" will be capped to 24h.

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Webhooks

When a human decides, VantaGate sends a signed HTTPS POST to your callback_url (up to 5 retry attempts with exponential back-off).

Request headers:

Content-Type: application/json

X-Vanta-Signature: sha256= User-Agent: VantaGate-Webhook/1.0

Signature verification (Node.js):

const crypto = require('crypto')

function verifyVantaSignature(rawBody, signature, projectSecret) { const expected = 'sha256=' + crypto .createHmac('sha256', projectSecret) .update(rawBody) .digest('hex') return crypto.timingSafeEqual( Buffer.from(expected), Buffer.from(signature) ) }

app.post('/webhook/vanta', express.raw({ type: 'application/json' }), (req, res) => { const sig = req.headers['x-vanta-signature'] if (!verifyVantaSignature(req.body, sig, process.env.VANTA_PROJECT_SECRET)) { return res.status(401).json({ error: 'Invalid signature' }) } const event = JSON.parse(req.body) if (event.status === 'APPROVED') { // ✅ Resume agent workflow } else if (event.status === 'REJECTED') { // ❌ Halt - check event.reject_reason } res.json({ received: true }) })

Your Webhook Signing Secret (VANTA_PROJECT_SECRET) is distinct from your API key. Find it in Dashboard → Project Settings.

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Building from Source

# Install dependencies

npm install

Build TypeScript

npm run build

Run the server directly

VANTA_API_KEY=YOUR_API_KEY_HERE npm start

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Advanced: MCP Config for Other Clients

Cursor / Cline / Windsurf

{

"mcpServers": { "vantagate": { "command": "npx", "args": ["-y", "@vantagate/mcp-server"], "env": { "VANTA_API_KEY": "YOUR_API_KEY_HERE" } } } }

With local build (development)

{

"mcpServers": { "vantagate": { "command": "node", "args": ["/absolute/path/to/dist/index.js"], "env": { "VANTA_API_KEY": "YOUR_API_KEY_HERE" } } } }

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Security

• Your X-API-KEY is hashed server-side - VantaGate never stores plaintext keys.
• Your slack_webhook_url is sent per-request and purged atomically after the decision. Zero retention.
• All payload data is encrypted at rest with AES-256 and destroyed after the human decision. It cannot be reconstructed.
• callback_url is validated against private IP ranges (SSRF prevention).
• All webhook deliveries are signed with HMAC-SHA256. Always verify signatures.

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License

MIT - see LICENSE

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Links

• Dashboard: https://vanta-gate.com/dashboard
• Full API Docs: https://vanta-gate.com/dashboard/docs
• Privacy Policy: https://vanta-gate.com/legal/privacy-policy
• Terms of Service: https://vanta-gate.com/legal/terms-of-service