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

Annotations already declare the write/safe profile (readOnlyHint=false, destructiveHint=false), and the description adds genuinely new behavior: an e-mail invite is sent and the plan's student limit is enforced. It stops short of describing what happens when the limit is exceeded or what identifier is returned.

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?

Purpose and side effect are front-loaded in the first clause, followed by required/optional fields and the plan constraint. The app-UI analogy ('like "Adicionar aluno"') is a small amount of filler but does not obscure the core 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?

With no output schema and only high-level annotations, the description covers the mutation's side effects, required inputs, and a key constraint, which is close to sufficient for an agent to call it correctly. Missing details are the response shape and limit-exceeded failure behavior.

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 88%, so the schema already documents each field including formats like YYYY-MM-DD and the email invite target. The description mostly restates the required/optional split that the schema's 'required' array already conveys, adding little beyond that.

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 and resource ('Adds a student to the trainer's account') and immediately characterizes the effect: an e-mail invite to install the app. It is clearly distinct from sibling creation tools like create_workout and schedule_class.

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?

States a real precondition ('Respects the student limit of the trainer's plan') and which fields are required vs optional, giving the agent clear context for when the call will succeed. It does not, however, name alternatives such as get_student for lookups or say what to do when the plan limit is hit.

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