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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive). The description adds real behavioral context beyond that: it discloses what is compared (published specs, calculated ratings, same-currency prices, missing inputs), the return (human comparison URL), and explicit limits ('cannot establish live availability or medical suitability').

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?

The core purpose is front-loaded, but the description is dense and mixes several distinct instructions (resolve first, compare, explain tradeoffs, can't do X, present as clickable link) into a long unsegmented block. Every clause is relevant, yet the presentation instruction ('keep each model and year identical to the returned records') reads as prompt-engineering bloat rather than tool semantics.

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 read-only, no-output-schema tool, the description is nearly complete: it covers inputs, comparison scope, limitations, and follow-up presentation. Only the absence of explicit sibling routing keeps it from 5.

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 coverage is 100%, so the schema documents both parameters; the description adds only that the identifiers must be 'exact' models with known catalogue slugs, which nudges meaning but provides no syntax or format detail. Baseline 3 when the schema carries the load.

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 clear verb and resource ('differences between two exact padel-racket models') and scopes it to catalogue-slug-known models, which differentiates it from get_racket/search. However, it does not name the siblings (get_racket, search_rackets) it is adjacent to, relying on implication rather than explicit contrast.

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 explicit preconditions ('Resolve ambiguous model names and years first') and a use case ('when a buyer wants the differences'), which is strong context. It lacks an explicit exclusion naming alternatives (e.g. 'use search_rackets when slugs are unknown'), so it falls short of 5.

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