Verify an email address's deliverability and status, checking MX records, disposable domains, and more to classify it as valid, risky, or invalid.
Verify an email address for deliverability and status
| Name | Required | Description | Default |
|---|---|---|---|
| Yes | |||
| options | No |
| Name | Required | Description | Default |
|---|---|---|---|
| Yes | |||
| checks | Yes | ||
| reason | Yes | ||
| status | Yes | ||
| metadata | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full responsibility for behavioral disclosure. It only says 'verify' without revealing that the tool likely performs network checks, uses timeouts, or has no side effects. No safety profile or operational behavior is disclosed.
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 efficient sentence with no filler. The core action is front-loaded, and it earns its place, though it sacrifices detail.
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?
Even with an output schema present, the description omits meaningful context: there is no mention of optional settings, what checks are performed (MX, disposable), or whether the operation is read-only. An agent can call it with just 'email', but has no guidance on customizing behavior or interpreting the verification scope.
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 0%, and the description mentions no parameters at all. It does not explain the 'email' field or the nested 'options' object with checkMx, timeoutMs, and checkDisposable. The agent must rely entirely on parameter names and defaults.
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 ('Verify'), a clear resource ('an email address'), and the purpose ('deliverability and status'). It is immediately distinguishable from the unrelated sibling tools (mcping, mchelp).
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 gives no guidance on when to use this tool versus alternatives, nor any prerequisites or context. There is no explicit or implicit direction about choosing verify_email over another tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.