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 beyond them: it discloses the failure semantics ('bij een onbekend id een JSON-RPC-fout') and that results carry discount code, partner link and permalink.

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 packs id format, return contents and error behavior with no filler. It is dense but every clause carries information; the only cost is that the semicolon-joined error note is buried late.

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?

An output schema exists, so return values needn't be explained, and annotations cover the safety profile. The description still covers the id constraint and the error case, leaving only the absence of sibling routing and the unaddressed markt parameter as minor gaps.

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 67% and the schema already documents markt and the context/meta fields reasonably well. The description's one genuine addition is the required id format (sp-p-<id> / sp-v-<id>), which the bare 'type: string' does not convey, putting it marginally above the baseline.

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 (fetch one product) plus the id shapes it accepts (sp-p-<id> / sp-v-<id>) and the enriched output form (UCP with discount code, partner link, permalink). The id format alone distinguishes it from the catalogue search siblings, though no sibling is named explicitly.

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?

There is no when-to-use guidance and no routing against alternatives such as search_catalog, zoek_producten or lookup_catalog. An agent must infer that this is the terminal step after an id has been discovered elsewhere.

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