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

Annotations already declare readOnly, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely new behavioral detail: the month-end sampling rule, the 1-60 month window with a 24-month default, and that a club page URL 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?

A single dense sentence that front-loads the return value before the parameters, with no filler. It is slightly overstuffed with parentheticals, but nothing is wasted.

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 only two parameters, no output schema, and full annotation coverage, the description supplies the essential call-shaping facts (slug source, month window, sampling semantics, URL in response). It stops short of describing the fields in each monthly record, which an agent might still want.

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 0%, so the description must carry the load and largely does: 'club' is defined as the slug from resolve, and 'months' is bounded 1-60 with a stated default of 24. Only the slug pattern constraint and what format the returned series takes are left unstated.

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 uses a specific verb ('Returns') on a specific resource ('442ball Power Rating month by month') scoped to one club, and clarifies the aggregation rule ('the last weekly value of each month'). An agent can distinguish this from the sibling 'club_rating' by the monthly time series framing.

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?

It gives an explicit prerequisite: the club slug must come from 'resolve', which prevents a whole class of failed calls. It does not state when to prefer this over 'club_rating' (current vs. historical), so the sibling routing is left implicit.

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