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Connectors
Connect

Connect to everything your agents need, without writing the infrastructure to get there.

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Enterprise-grade controls to ensure your agent always meets security & compliance standards.

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Maximise agent efficiency – faster responses, increased accuracy, fewer tokens used.

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Whois MCP Server
for AI Agents

Connect your AI agent to StackOne's Whois MCP server and give it 20 MCP tools out of the box. Auth, tool execution, and security all managed.

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Whois MCP Server
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Coverage

20 Agent Actions

Create, read, update, and delete across Whois — and extend your agent's capabilities with custom actions.

MCP Actions → Build Actions →

Authentication

Agent Tool Authentication

Per-user OAuth in one call. Your Whois MCP server gets session-scoped tokens with zero credentials stored on your infra.

Agent Auth →

Security

Agent Protection

Every Whois tool response scanned for prompt injection in milliseconds — 88.7% accuracy, all running on CPU.

Prompt Injection Defense →

Performance

Max Agent Context. Min Cost.

Free up to 96% of your agent's context window to enhance reasoning and reduce cost, on every Whois call.

Tools Discovery →

What is the Whois MCP Server?

A Whois MCP server lets AI agents read and write Whois data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Whois MCP server ships with 20 pre-built actions, fully extensible via the Connector Builder — plus managed authentication, prompt injection defense, observability, and agent execution runtime. Connect it from MCP clients like Claude Desktop, Claude Code, Cursor, Goose, and VS Code, or from agent frameworks like OpenAI Agents SDK, LangChain, and Vercel AI SDK.

All Whois MCP Tools

Every action from Whois's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.

Other (20)

  • Get Account Balance

    Get the remaining API credits for each subscribed product.

  • WHOIS Lookup

    Get the WHOIS record for a domain or IP.

  • WHOIS History

    Get the historical WHOIS records for a domain.

  • DNS Lookup

    Get DNS records for a domain.

  • Check Domain Availability

    Check whether a domain is available for registration.

  • Subdomains Lookup

    Discover subdomains for a domain.

  • Domain Reputation

    Get the reputation score for a domain.

  • SSL Certificates Lookup

    Get the SSL/TLS certificate chain for a domain.

  • Website Categorization

    Get the content categories for a domain.

  • Verify Email

    Verify an email address.

  • IP Geolocation

    Get geolocation and network data for an IP address.

  • IP Netblocks Lookup

    Get the netblock (IP range) records that an IP, ASN, or organization belongs to.

  • Reverse WHOIS Search

    Find domains matching WHOIS record search terms.

  • Reverse NS Lookup

    Find domains served by a name server.

  • Reverse MX Lookup

    Find domains using a mail server.

  • Reverse IP Lookup

    Find domains hosted on an IP address.

  • Brand Alert

    Find newly registered or dropped domains matching brand terms.

  • Registrant Alert

    Find newly registered or dropped domains matching registrant terms.

  • Capture Website Screenshot

    Capture a screenshot of a web page.

  • Threat Intelligence Lookup

    Look up threat intelligence for an indicator of compromise.

Set Up Your Whois MCP Server in Minutes

One endpoint. Any framework. Your agent is talking to Whois in under 10 lines of code.

MCP Clients

Claude Desktop setup guide
Claude Code setup guide
Cursor setup guide
Goose setup guide

Agent Frameworks

Claude Desktop
{
  "mcpServers": {
    "stackone": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote@latest",
        "https://api.stackone.com/mcp?x-account-id=<account_id>",
        "--header",
        "Authorization: Basic <YOUR_BASE64_TOKEN>"
      ]
    }
  }
}

Platform Resources

MCP Code Mode: Keeping Tool Responses Out of Agent Context

Anthropic's code_execution processes data already in context. Custom MCP code mode keeps raw tool responses in a sandbox. 14K tokens vs 500.

11 min

Comparing BM25, TF-IDF, and Hybrid Search for MCP Tool Discovery

Benchmarking BM25, TF-IDF, and hybrid search for MCP tool discovery across 916 tools. The 80/20 TF-IDF/BM25 hybrid hits 21% Top-1 accuracy in under 1ms.

10 min

Indirect Prompt Injection Defense for MCP Tools: A Technical Guide

MCP tools that read emails, CRM records, and tickets are indirect prompt injection vectors. Here's how we built a two-tier defense that scans tool results in ~11ms.

12 min

MCP vs A2A: Architecture, Security, and When to Use Each

MCP vs A2A: what each protocol standardizes, how they differ, their shared security risks including indirect prompt injection, and when to use one, both, or a hybrid architecture.

12 min

MCP vs API: What 200+ Connector Builds Taught Us

MCP wraps APIs, it doesn't replace them. After building 200+ connectors that serve both, here's when each approach wins.

14 min read

Whois MCP Server FAQ

Does StackOne have a Whois MCP server?
Yes. StackOne offers a hosted Whois MCP server with 20 pre-built actions, and every action is tested and QA'd by StackOne. Connect it to Claude, Cursor, and any other MCP client, or to any agent framework through the AI Action SDK. It ships with managed agent authentication, prompt injection defense, and tool discovery with server-side execution that preserve your agent's context window and keep reasoning performance.
Whois MCP server vs direct API integration — what's the difference?
A Whois MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Whois. A Whois MCP server is for AI agents — MCP clients like Claude and Cursor, plus framework agents built with OpenAI, LangChain, or Vercel AI — discovering and calling Whois at runtime. StackOne provides both.
How does Whois authentication work for AI agents?
Whois authentication for AI agents works through a StackOne Connect Session. Create one via the dashboard or the SDK — you get an auth link and ready-to-paste config for Claude Desktop, Cursor, and other MCP clients. Your user authenticates their own Whois account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via origin_owner_id.
Are Whois MCP tools vulnerable to prompt injection?
Yes — Whois MCP tools can be vulnerable to indirect prompt injection. Any tool that reads user-written content — documents, messages, tickets, records, or free-text fields — is a potential vector. StackOne Defender scans every tool response before it enters the agent's context — regex patterns in ~1ms, then a MiniLM classifier in ~4ms. 88.7% accuracy, CPU-only.
What is the context bloat of a Whois agent and how do I avoid it?
Context bloat happens when Whois tool schemas and API responses eat your Whois agent's memory, preventing it from reasoning effectively. A single Whois query can return a massive JSON response, and connecting multiple tools compounds the problem. Tools Discovery and Code Mode reduce context bloat — loading only relevant tools per query and keeping raw responses out of the agent's context.
Can I limit which actions my Whois agent can access?
Yes — you can limit which actions your Whois agent can access directly from the StackOne dashboard. Toggle actions on or off, or restrict them to specific accounts, with no code changes to your agent. Session tokens can be scoped to exact actions so if one leaks, exposure stays contained.
Can I create custom agent actions for my Whois MCP server?
Yes — you can create custom agent actions for your Whois MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Whois's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a Whois MCP server?
Skip a Whois MCP server if your integration is purely software-to-software — direct Whois API integration is simpler when no AI agent is involved. For deterministic, compliance-critical operations (financial transactions, regulatory reporting), direct API gives you predictable behavior without agent-driven decision-making. MCP shines when AI agents need to dynamically discover and call Whois actions at runtime.
What AI frameworks and AI clients does the StackOne Whois MCP server support?
The StackOne Whois MCP server supports both. MCP clients (paste-and-go apps): Claude Desktop, Claude Code, Cursor, VS Code, Goose. Agent frameworks (code SDKs you build with): OpenAI Agents SDK, Anthropic, Vercel AI, Google ADK, CrewAI, Pydantic AI, LangChain, LangGraph, Azure AI Foundry.

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All the tools you need to build and scale AI agent integrations, with best-in-class connectivity, execution, and security.

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