Connect an email validator to AI assistants with a public MCP server

An assistant needs an actual tool connection to check email routing. Finding a blog post about a validator does not give the assistant permission or a connection to run it.

Heffl provides a public email_verify MCP tool and a JSON API backed by the same engine. The integration guide documents the endpoints, result fields and anonymous limits.

Add the remote MCP server

If your client supports remote MCP, add this server URL:

https://api.heffl.com/api/public-tools/mcp

Choose no authentication and enable the connector for the conversation or agent. This endpoint uses stateless Streamable HTTP. Opening it in a browser sends GET, which returns 405; that is not a connection test.

Claude's custom connector flow supports No sign in. OpenAI documents no-auth tool declarations. Perplexity has announced open-auth remote connectors, and OpenClaw documents outbound MCP configuration. Availability depends on your account, client version and organization policies.

Give the assistant a clear instruction

Ask it to check one address and explain the evidence. For example: “Use Heffl's email_verify tool to check this address. Tell me whether the mailbox was checked and whether any result is inconclusive.”

The tool accepts one email field. It does not accept SMTP hosts, ports, proxies or sender identities from callers. An unknown result must not become “valid” in the assistant's answer.

Use HTTP when MCP is unavailable

A personal agent with HTTP tool support can use the OpenAPI specification. Register the POST operation as a tool using the runtime's native integration mechanism. Keep the same uncertainty handling and respect Retry-After when a rate limit is reached.

Discovery is a separate step

Search-indexed documentation helps people and browsing agents find an integration. MCP registries help clients discover server metadata. Assistant directories have their own publishing and review processes. None of these guarantees that an assistant will choose or install a tool automatically.

Start with the browser validator to see how its evidence is presented, then connect your client using the integration guide.