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

Annotations already cover the safety profile (readOnly=true, destructive=false, openWorld=false), so the bar is lower; the description adds genuine behavioral context by disclosing that unknown ids are reported rather than rejected, and that each returned variant carries inputs[] echoing the requested id. This error-tolerance detail is not derivable from the annotations.

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 with the retrieval action first, followed by format detail and error semantics. Two clauses share one sentence and the embedded parenthetical is dense, but nothing is wasted.

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 need not be explained; the description supplies the two things an agent actually needs beyond the schema — accepted id syntax and unknown-id behavior. Market routing and the 20-id batch cap live in the schema, so nothing material is missing.

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?

The ids array has no description in the schema, and the description compensates by spelling out the accepted id syntaxes (sp-p-<id>, sp-v-<id>, bare post-id), which is real added meaning. The remaining parameters (markt, filters, context, attribution) are already documented in the schema, so 4 is appropriate rather than 5.

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 ("Haal producten op") and resource ("/via hun UCP-id") and even enumerates accepted id formats (sp-p-<id>, sp-v-<id>, bare post-id). The bulk-by-id nature is clear, though it never explicitly contrasts itself with the sibling search_catalog or get_product.

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 only implied: it is evident you call this when you already hold ids, but there is no explicit when-to-use/when-not statement and no pointer to search_catalog for text queries or get_product for single fetch. The caller must infer the boundary themselves.

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