Validate an email address by checking its format, MX records, domain resolution, disposable domain status, and role-based detection.
Inspect an email address. Checks format validity, MX records, domain resolution, disposable domain detection, and role-based address detection.
| Name | Required | Description | Default |
|---|---|---|---|
| Yes | Email address to inspect (e.g., "hello@example.com") |
Changes observed during successful MCP inspections.
v1.4.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The readOnlyHint annotation already communicates this is a non-destructive operation, so the description's burden is reduced. The description adds the specific checks performed, which is useful, but it does not disclose what the returned result looks like, whether failures are partial, or that network lookups like MX and domain resolution may be non-deterministic. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two concise sentences. The first sentence names the action and resource, and the second immediately lists the specific checks. There is no filler, and the most important identifying information is front-loaded.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple single-parameter read-only tool, the description covers the essential behavior well. The only minor gap is the absence of any statement about return format, but since no output schema exists, a short note about the returned findings would strengthen it. Still, the listed checks make the general result sufficiently predictable.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, and the single 'email' parameter is already clearly documented with an example. The description does not add new parameter-level detail, but given full schema coverage, the baseline of 3 is appropriate; no compensation is needed.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb ('Inspect') and resource ('email address'), then enumerates the concrete checks performed: format validity, MX records, domain resolution, disposable domain detection, and role-based detection. This makes the tool's purpose unambiguous and differentiates it from sibling tools like validate_email_auth, which has a narrower scope.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description clearly implies when to use this tool: whenever an email address needs a multi-faceted inspection covering syntax, domain infrastructure, disposability, and role accounts. It does not explicitly name alternatives or exclusions, but the listed check categories provide enough guidance for an agent to select it over related tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.