Server Quality Checklist

Tool Scores

• search_listingsA
  4/5.0
  Behavior5/5

  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.

  Conciseness5/5

  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.

  Completeness4/5

  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.

  Parameters3/5

  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.

  Purpose5/5

  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.

  Usage Guidelines2/5

  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.

• get_sellerA
  4.2/5.0
  Behavior4/5

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

  Annotations already declare read-only and open-world; the description adds that the profile is public (no auth needed) and that the ID comes from search results, which helps the agent understand the source and safety. It does not detail error handling, but that's beyond what's expected here.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  Two short sentences, front-loaded with the action and resource, and the second sentence adds purpose without redundancy.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness4/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  For a read-only profile fetch with only one required parameter, the description provides enough context on what the tool does, where the ID comes from, and how the result can be used. Without an output schema, it could explain return fields, but the purpose makes the presence of profile information sufficient.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  The schema already fully describes both parameters with 100% coverage, including the numeric seller id and optional seller name. The description's mention of 'numeric seller id' reinforces the schema but adds little new meaning, so baseline of 3 applies.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the tool fetches a seller's public profile by numeric seller id, and differentiates it from listing-related siblings by focusing on seller information. It also explains the use case of determining private vs shop, which further clarifies purpose.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines4/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  Provides a clear context: useful for judging seller type after obtaining the ID from search results. It does not explicitly name alternatives or when-not-to-use, but the context is sufficient to infer when to call it.

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

• get_listingA
  4.4/5.0
  Behavior4/5

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

  Annotations already declare readOnlyHint and openWorldHint, so the safety profile is known. The description adds useful behavioral context by detailing the exact fields returned (shipping carrier, counts, dates, etc.), which is not otherwise disclosed. It stops short of error-handling details, but the annotations lower the burden.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is two sentences and quick to read. The first sentence states the core function, and the second lists the value-added fields. No unnecessary words or repetition.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness4/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  With no output schema, the description compensates by listing the fields returned, giving the agent a clear idea of the response content. It doesn't mention error cases or the response format, but for a simple read-only fetch of a single resource, it is sufficiently complete.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  The input schema has 100% coverage for the single parameter 'listing', with a description explaining it can be an id or a full URL. The tool description merely repeats 'by id or URL' without adding new meaning, so it doesn't elevate beyond the baseline score.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the tool fetches full detail for a single listing by id or URL, and it distinguishes itself from search_listings by enumerating the additional fields it returns. The verb 'fetch' and the resource 'listing' are specific, making the purpose unmistakable.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines5/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description explicitly says it 'Adds what search does not carry,' which clearly informs when to use this tool instead of search_listings. This provides direct guidance on tool selection relative to a sibling tool.

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