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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuinely new behavioral context: that prior links and codes are invalidated by the call, and a rate limit ('a few per hour'). That is useful disclosure beyond the structured fields, though the rate limit is vague and no auth requirements are mentioned.

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 short sentences, zero filler, and the core action is front-loaded ahead of the side-effect and rate-limit caveats. Every sentence 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 parameterless mutation with no output schema, the description covers the action, the destructive side effect on existing tokens, and the rate constraint. Combined with annotations that carry the idempotency and openness flags, an agent has everything needed to call it 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?

The tool takes zero parameters (100% coverage of an empty schema), so the baseline is 4. There is nothing for the description to disambiguate, and it correctly does not invent parameters.

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+resource combination ('Send the owner a new confirmation email') plus what the email contains ('link and code'). It is largely distinguishable from the sibling verify_email, though the description never names that counterpart explicitly to reinforce the resend-vs-verify distinction.

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?

Usage is implied by the verb 'resend' plus the warning that earlier links and codes stop working, which hints at when a caller would reach for it. However, there is no explicit statement of when to use this versus verify_email or any precondition (e.g. email must be unverified), so guidance stays at the implied level.

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