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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile needs no restating. The description earns credit for disclosing the response payload (current price, previous price, discount, rating, sales, store, verification date, buy link), which matters because there is no output schema.

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: the lookup key comes first, the returned fields follow as a compact enumeration. No filler, no redundancy with the title.

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 one-parameter read tool with full annotation coverage and no output schema, the definition supplies the missing return-value information, which is the main gap it needed to close. Minor omission: it doesn't say what happens when the id is unknown or the URL points to a removed offer.

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% and the schema's own parameter description already says 'Id da oferta (número) ou URL https://cloo.be/ofertas/…', which the description essentially repeats. It adds no extra format rules, normalization behavior, or error semantics for a malformed id/URL, so the baseline of 3 applies.

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+resource (fetch the details of an offer) with its two accepted keying modes (id or cloo.be URL) and enumerates exactly which attributes come back. It implicitly separates itself from the list-oriented siblings (buscar_ofertas, ofertas_da_categoria, ofertas_em_alta) by being a single-offer lookup, but never names them.

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?

Usage is implied rather than stated: you need an offer id or an offer URL, so this is the follow-up call after a search, not a discovery call. There is no explicit 'use buscar_ofertas if you only have a keyword' routing, so an agent must infer the alternative from the required `id`.

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