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

Annotations already declare readOnly/idempotent/openWorld=false, so safety is covered; the description adds genuinely useful context beyond that, namely that every statement carries a source, that today's lowest promotion is included, and that the tool withholds a verdict. It does not cover pagination or result size, so it falls short of a 5.

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?

Front-loaded with the noun phrase and its contents, then usage, then the no-argument case — a logical order. The middle sentences are dense and run long, but nearly every clause contributes information an agent needs.

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?

There is no output schema, so the description carries the burden of describing the return value, and it does: models compared with specs and promotions, feature explanations with when-you-need-it guidance, sourced facts, and the list-of-guides fallback. An agent can decide whether to call it and predict the shape of the answer.

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 baseline is 3; the description goes further by clarifying that the type may be Dutch or English, giving concrete synonyms ('airfryer', 'heteluchtfriteuse'), and explaining the no-argument fallback of returning all guides.

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?

Opens with a specific verb+resource ('A researched buying guide for a kind of product') and immediately enumerates the contents: compared models with key specs and today's lowest promotion, feature explanations, and sourced facts. It is clearly distinguishable from sibling tools such as get_deal or search_deals, which deal with individual deals rather than guide content.

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?

Gives explicit when-to-use conditions with real query examples in both Dutch and English ('beste airfryer', 'welke wasmachine kopen'), and states a clear boundary: it does not crown a winner but presents cited test and buyer scores. It also states the behavior when no type is supplied (returns the list of guides).

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