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

Annotations already declare this is a non-read-only, open-world, non-destructive operation, so the safety profile is covered. The description adds the return value ('the address it went to') and the ownership constraint, but says nothing about link expiry, rate limiting, or what happens if the student has no e-mail on file.

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 waste: the action and recipient scope come first, then the return value. 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 e-mail trigger with annotations and no output schema, the description covers action, trigger condition, recipient scope and return value. Only failure modes (no e-mail on record, delivery failure, link lifetime) are unaddressed.

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% and the schema already explains that studentId comes from list_students. The description only adds the ownership nuance ('one of the trainer's students'), which is marginal added meaning over the schema — baseline 3 applies.

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?

Names a specific verb (e-mails) plus the exact resource (link to create a new password) and the recipient scope ('one of the trainer's students'). It is unmistakable against siblings like send_message, send_checkin or invite_student, though it never explicitly names those alternatives.

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 parenthetical '(when the student forgot it)' gives a clear triggering condition, and the ownership phrasing limits it to the trainer's own students. It stops short of stating exclusions, e.g. what to do if the student never had an account or already has a valid link.

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