Search marktplaats.nl

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

Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds substantial behavioral context beyond these: the meanings of delivery values ('shipping', 'pickup', 'both', 'unknown'), that paid placements are included and flagged with isSponsored, and that prices are in euros with null for bids/no-price listings. No contradiction with 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?

The description is five concise sentences that are front-loaded with the core purpose, followed by essential response semantics. Every sentence provides useful information with no redundancy or fluff.

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?

With no output schema, the description carries the burden of explaining return values. It covers key fields (price, condition, delivery, category specs, location, seller, isSponsored) and clarifies delivery and price edge cases. However, it does not describe the overall response envelope (e.g., list structure, pagination metadata), leaving some ambiguity.

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 description coverage is 100% (all 12 parameters have descriptions). The tool description does not add parameter-level semantics; its delivery and price details are about response fields, not input parameters. Thus, it stays at the baseline 3.

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 clearly states the tool's function with a specific verb ('Search') and resource ('marktplaats.nl (Dutch classifieds)'). It also lists the returned fields, distinguishing it from sibling tools like get_listing and get_seller, which are focused on retrieving individual items rather than searching.

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?

The description provides no explicit guidance on when to use this tool versus alternatives. There is no mention of get_listing or get_seller, and no exclusions or prerequisites are given. The agent must infer usage solely from the tool name and basic function description.

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