netintel_email_verify

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

With no annotations, the description carries the full burden and does most of it: it discloses the return shape (boolean-first deliverable/safe_to_send plus a machine-readable reason) and, critically, the scope limit 'DNS-level check only, no SMTP mailbox probe', which prevents the agent from over-trusting a positive result. It stops short of stating auth requirements or rate limits, so it is strong but not exhaustive.

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?

Three dense clauses with zero filler, the capability summary front-loaded and the sibling routing at the end. Every element (checks performed, output shape, scope limit, alternative) 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?

No output schema and no annotations exist, so the description is the only source, and it covers the important ground: what is checked, the boolean-first output keys, and the DNS-only limitation. It could go further by naming the possible 'reason' values, which would let the agent interpret a negative result, so it is complete but not fully so.

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 0% for the single 'email' parameter, but the parameter is self-evident and the description supplies the relevant meaning: the input is an email address to be validated, and what is validated about it is spelled out (syntax, MX, provider classification). This compensates adequately for the undocumented schema, though it adds no format constraints or examples.

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?

Starts with a specific verb+resource ('Validate an email address') and immediately enumerates what is checked: syntax, MX, disposable/role/free-provider detection. It also names the sibling netintel_email_intel and the axis that separates them (yes/no gate vs. scored trust report), so the agent can disambiguate without opening either 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?

The phrase 'email verification before you send' gives the operative scenario, and the final sentence explicitly routes the agent elsewhere ('For a scored trust report instead of a yes/no gate, see netintel_email_intel') with the deciding condition. Both when-to-use and the alternative are stated.

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