email-verify

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

No annotations exist, so the description carries the full behavioral burden. It usefully discloses billing ('Cost: 1 credit') and the result categories, but says nothing about permissions, rate limits, latency, whether a credit is charged on failure, or how the verdict is expressed — significant gaps for a zero-annotation tool.

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 short sentences with zero filler; the functional outcome is front-loaded and the cost caveat follows. Nothing could be trimmed without losing information.

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 one-parameter, no-output-schema lookup, the description covers purpose, result categories, and cost, which is nearly everything an agent needs. Only the behavioral layer (failure modes, credit charging rules) remains thin.

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?

There is a single parameter and schema description coverage is 100%, so the schema already documents 'Email to verify.' The description adds no format, normalization, or validation guidance beyond that, making 3 the appropriate baseline.

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?

States a specific verb (check) and resource (an email) plus the three concrete outcomes it reports: deliverable, catch-all, disposable. That is much stronger than a tautology, but it never distinguishes itself from the nearby 'emails' and 'profiles' siblings, which an agent might confuse with verification.

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 intended use (verify an address before relying on it) is implied by the phrasing but never stated, and there are no exclusions, prerequisites, or alternative tools named. Adequate but leaves the agent to infer when this beat is worthwhile.

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