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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), so the description earns credit for extra behavior: the difference is only emitted when both ratings share a scale, and otherwise the response explains why it is withheld. That pre-empts a confusing partial result. Return shape beyond that (fields, ordering) is not described.

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, front-loaded with the return value, then the conditional behavior, then the parameter source. Nothing is redundant and every sentence adds 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 simple two-parameter read with no output schema, the description covers what is returned, the conditional withholding rule, and the parameter provenance — enough for correct invocation. Minor gap: no hint about what the response contains when the difference is withheld or how ratings are labeled per club.

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 compensate, and it does the most important part: both parameters are club slugs sourced from resolve, not free-text names. It does not restate the slug pattern or clarify ordering of club_a vs club_b, but the critical type/derivation is covered.

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 ('Returns two clubs' latest 442ball Power Ratings side by side') and makes the two-club comparison scope unmistakable, which cleanly separates it from the single-club sibling club_rating and the list-style rankings/league_index tools.

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 clause 'Takes two club slugs from resolve' establishes the prerequisite step (resolve the clubs first) and is genuinely useful routing context. However, it never says when to prefer this over club_rating called twice, nor any exclusion or failure condition beyond the withholding rule.

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