Checks only whether an email address uses a known disposable/temporary email domain. For syntax, MX, disposable and role-account checks in one call, use email_verify.
| Name | Required | Description | Default |
|---|---|---|---|
| Yes | Email address to check against a list of known disposable/temporary email domains. |
Changes observed during successful MCP inspections.
Input schema / properties / email / descriptionPrevious value: -""New value: +"Email address to check against a list of known disposable/temporary email domains."Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds the specific behavioral scope (checks against a known list) and explicitly limits it to only disposable domains, which is useful beyond annotations. 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?
Two sentences, front-loaded with the core purpose, and the alternative is mentioned in the second sentence. No filler or redundancy. Every word earns its place.
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 single-parameter tool with comprehensive annotations and a clear alternative routing, the description is complete. It explains what the tool does, what it does not do, and when to use the sibling. No output schema is needed for such a simple boolean-style check, and nothing critical is missing.
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 parameter description already explains the email address is checked against disposable domains. The tool description does not add additional parameter semantics beyond what the schema provides, but that is acceptable given full coverage. Baseline 3 is appropriate.
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 ('Checks') and resource ('email address') and clearly scopes it to disposable/temporary email domains. It distinguishes itself from the sibling email_verify by naming what it does NOT do, making the purpose unambiguous even without opening the schema.
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?
Explicitly states when to use this tool versus the alternative: 'For syntax, MX, disposable and role-account checks in one call, use email_verify.' This provides clear routing logic, telling the agent exactly when to choose this tool (only disposable check needed) and when to choose the sibling.
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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