Validate bulk email lists using RFC syntax checks, DNS MX lookups, disposable-domain detection, and role-account scoring to clean contacts before outreach.
Verify email addresses via RFC syntax, DNS MX records, disposable domain detection, and role-account scoring.
| Name | Required | Description | Default |
|---|---|---|---|
| emails | Yes | Emails to verify | |
| maxItems | No |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden; it does disclose the specific verification checks performed, which is useful context beyond the schema. However, it does not explain whether the tool makes network/DNS calls, whether it is read-only, how failures are reported, or what the response contains, leaving meaningful gaps.
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 a single front-loaded sentence with no wasted wording. Its brevity is appropriate, though the same sentence could have carried a bit more operational detail without becoming bloated.
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?
There is no output schema, so the description should explain what verification results look like, but it does not. It also omits the maxItems parameter behavior and any limits or side effects relevant to a bulk verification tool, leaving the definition materially incomplete.
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 coverage is only 50%, with 'maxItems' undocumented in both the schema and the description. The description says nothing about batch limits, default maximum of 25, or how the 'emails' array is processed, so it fails to compensate for the coverage gap.
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 states a specific verb and resource: 'Verify email addresses,' and enumerates the verification techniques used (RFC syntax, DNS MX, disposable domain detection, role-account scoring). This is clear enough for an agent to understand the tool's function, though it does not explicitly differentiate it from sibling tools.
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 offers no when-to-use guidance, no alternatives, and no exclusions. An agent must infer from the verb alone that this is for validating a list of email addresses rather than, for example, enriching or searching them.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.