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

Annotations already declare readOnlyHint=false, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds that this sends an outbound email and operates on exactly one ID, but it does not mention ICANN-driven rate limits, throttling, or what happens if the ID is stale — the main behavioral risks for a resend 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?

One sentence, no filler, with the action and the ID source front-loaded. Nothing could be removed 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 single-parameter, non-destructive send action with annotations covering the safety profile and no output schema, the description supplies everything essential: what it sends, for which record, and where to get the ID. Only missing rate-limit/retry behavior keeps it from a 5.

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 verification_id parameter, so the description must compensate — and it does by naming the source tool (list_unverified_contacts) and emphasizing 'one', which implies a single opaque ID rather than a batch. It does not describe the ID format or validity lifetime, keeping it below a 5.

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 (send again / resend), a specific resource (the ICANN verification email), and a specific scope (one verification_id). It also names the sibling list_unverified_contacts as the source of the ID, so an agent can distinguish it from other domain tools without opening a 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 word 'again' plus the pointer to list_unverified_contacts makes the intended workflow explicit: fetch unverified contacts, then resend for one of them. It stops short of stating exclusions (e.g., don't call repeatedly, rate limits, or when to use set_contacts instead), so it is clear context but not full when/when-not guidance.

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