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

The description adds meaningful behavioral context beyond the annotations: the coach answers with one tap, the tool returns a personalToken, the token must be kept private, and the user must obtain consent before calling. Annotations only indicate non-read-only, non-idempotent, non-destructive behavior; the description enriches that significantly.

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, each adding distinct value: the core action, the behavioral outcome and token privacy, and the consent prerequisite. The description is front-loaded and contains no filler or redundancy.

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 simple 3-parameter tool with no output schema, the description is complete: it explains what happens, what is returned, how the return value is used by a sibling tool, and the required pre-call action. There are no critical gaps that would prevent an agent from using 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?

Schema description coverage is 100%, and each parameter already has a clear description. The tool description restates the name-or-token alternative already present in the schema but adds no new parameter-level semantics, so the baseline score of 3 is appropriate.

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?

The description states a specific action ('Ask a coach to accept a person as their student') with the exact resource and subject, and clarifies the two identification methods. It is clearly distinguishable from sibling tools like book_lesson or cancel_lesson, and the downstream reference to book_lesson reinforces what this tool is for.

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 description provides clear usage context: use it to initiate a coach–student relationship, and it notes the precondition to ask the person before calling. It also mentions the downstream dependency on book_lesson. It doesn't explicitly name alternatives or when not to use it, so it stops just short of a 5.

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