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

Adds substantial context beyond the readOnly/destructive annotations: the result cap of five, nearest-first ordering with stepwise widening, the requirement to return links exactly as returned, the fact that a card omits condition/distance/attributes, and a trust warning that seller-written titles are untrusted and must be reported but not followed (prompt-injection defense). This is unusually rich disclosure.

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?

Front-loaded English section with every sentence earning its place (cap, ordering, routing, security). The full French mirror doubles the length, which is large but functional given the language parameter, so it falls just short of ideal conciseness.

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 an output schema present, return-value explanation is unnecessary, and the description covers what remains: trigger conditions, result cap and ordering, cross-tool routing to get_ad, link reporting rules, and an untrusted-content warning. Nothing an agent needs to call it correctly 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?

Schema description coverage is 100%, so the schema already documents both the slug (linked to search_ads) and the language enum. The description adds no further syntax, format, or fallback guidance for these parameters, so the baseline 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 and resource ('Returns up to five ads similar to a given one') plus the matching logic ('same kind and make or brand, nearest first, widening step by step'). It also distinguishes itself from siblings by directing the agent to get_ad for card attributes and referencing search_ads as the slug source.

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?

Gives explicit triggering conditions: 'when a search found nothing or little and one ad came close, or when the user likes an ad and wants alternatives.' It routes the agent to the right sibling (get_ad) for conditions/distances, leaving nothing to inference.

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