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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds real value by specifying the return is prose ('in words') covering three named topics, which tells the agent the shape of the content without an output schema. It does not state length or that no numbers/current ratings are returned, which would fully close the gap.

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 front-loaded sentence that names the action, the subject domain, and the three content areas with no filler. Nothing in it should be cut.

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, the description carries responsibility for describing the return, and it does by enumerating the topics covered and stating the output is textual. Minor gaps remain – no indication of length, of whether the current ratings are included, or of how to get the version value separately – but an agent can call this confidently.

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, so there is nothing for the description to disambiguate. Baseline 4 applies; the description correctly implies no arguments are needed to retrieve the methodology.

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 and resource – it 'explains in words how 442ball calculates its club Power Ratings and league strength' – and enumerates the covered topics (band meaning, method version). This implicitly separates it from data-returning siblings like club_rating, league_strength, and rankings, which yield numbers rather than prose, though no sibling is named.

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 usage context is implied: call this when you need an explanation of the ratings rather than the ratings themselves. There is no explicit when-to-use or when-not-to-use statement, and no sibling is called out as the alternative for numeric lookups.

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