Kempt Horizon Data Toolkit

Validate email

validate_email

Read-only

Check an email address: syntax, MX records, disposable/role/free-provider flags, typo suggestion. Returns verdict and score.

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": "validate_email"
  }
}

Input Schema

Name	Required	Description	Default
`email`	Yes	Email address to check
`checkMx`	No	Look up MX records over DNS-over-HTTPS

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 26, 2026

TDQS

A3.5/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered; the description adds that it returns a verdict and score. It does not disclose the network cost of MX lookups (latency, possible failures) or what a 'verdict' looks like, which matters since there is no output schema.

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

Conciseness5/5

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

One compact sentence with the capability list front-loaded and zero filler. Every clause (syntax, MX, flags, typo suggestion, return shape) earns its place.

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

Completeness3/5

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

The tool is simple (2 params, 1 required), but it makes live external lookups and has no output schema, so the description should say more about the returned verdict/score and whether MX failures degrade the result. As written it is adequate but leaves the return contract underspecified.

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 both the email and checkMx parameters are already documented in the schema. The description's mention of MX records loosely connects to checkMx but adds no format or constraint detail beyond the structured data, so baseline 3 applies.

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

Purpose4/5

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

States a specific verb and resource ('Check an email address') and enumerates the exact checks performed (syntax, MX, disposable/role/free-provider flags, typo suggestion), which is far more informative than the title. It does not name its sibling validate_emails to confirm singular-vs-batch scope, but the singular phrasing implies it.

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

Usage Guidelines3/5

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

Usage is implied by the nature of the tool (validate before signup/send), but no explicit when-to-use, when-not-to-use, or routing to validate_emails for bulk input is given. Nothing is misleading, but the agent must infer the choice between siblings.

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

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