Instantly MCP Server

verify_email

Check email address validity using the Instantly MCP Server to ensure deliverability and maintain contact list accuracy.

Instructions

Verify if an email address is valid. IMPORTANT: This feature may require a premium Instantly plan or specific API permissions. If you receive a 403 Forbidden error, check: 1) Your Instantly plan includes email verification, 2) Your API key has the required scopes, 3) Contact Instantly support to confirm feature availability.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "email": "<email>"
    },
    "name": "verify_email"
  }
}

Input Schema

Name	Required	Description	Default
`email`	Yes	Email address to verify (must be valid email format)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Sep 21, 2025

TDQS

A4.1/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behavioral traits: it's a validation operation (implied read-only), discloses potential access restrictions (premium plan requirements, 403 errors), and provides troubleshooting guidance. It doesn't mention rate limits or response format details, but covers critical operational constraints.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is appropriately sized and front-loaded with the core purpose first, followed by important operational details. The troubleshooting list is somewhat lengthy but necessary for the access constraints, making it reasonably efficient overall.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter validation tool with no annotations and no output schema, the description provides good contextual completeness. It covers purpose, usage context, and critical behavioral constraints (access requirements, error handling). The main gap is lack of output format details, but otherwise it's quite comprehensive given the tool's simplicity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already fully documents the single 'email' parameter. The description adds no additional parameter information beyond what's in the schema, maintaining the baseline score of 3 for adequate coverage through structured data alone.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose with a specific verb ('verify') and resource ('email address'), and it distinguishes this tool from all sibling tools which focus on campaigns, leads, accounts, or lists rather than email validation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context about when to use this tool (to verify email validity) and includes important prerequisites (premium plan, API permissions). However, it doesn't explicitly state when NOT to use it or name specific alternatives among the sibling tools.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.