email-verify

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

No annotations are provided, so the description carries full behavioral disclosure burden. It details the specific checks (syntax, disposable domain via Kickbox, DNS MX via Cloudflare DoH) and the output format (score and verdict). While it does not mention rate limits or side effects, the tool is a validation check and likely read-only; the disclosure is adequate.

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 three sentences, each earning its place: first states the core function, second details checks and output, third lists use cases. It is front-loaded and avoids filler or repetition.

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?

Given the simple single-parameter input and no output schema, the description fully covers what the tool does and what it returns (quality score and verdict). The use cases and technical details are sufficient for an agent to understand and invoke the tool correctly.

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 100% with one parameter ('email') described as 'Email address to validate (e.g. 'user@example.com').' The description does not add meaning beyond the schema; it explains the validation process but not the parameter format or constraints. Baseline 3 is appropriate since the schema already contains sufficient documentation.

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 clearly states the tool performs email validation and quality scoring, specifying RFC-5322 syntax, disposable domain detection, DNS MX check, and output quality score with verdicts. This is a specific verb-resource combination that distinguishes it from the many sibling tools, none of which appear to focus on email validation.

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 explicitly mentions use cases: 'lead qualification, form validation, and filtering bot signups.' This provides clear context for when to use the tool. It does not exclude any scenarios or reference alternative tools, but the guidance is sufficiently strong for an agent to decide.

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