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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, and the description adds substantive context on top: no scraping, no fact verification, not legal advice, no media generated, no listing stored or changed, and operational call metrics are logged. That last detail is a genuinely useful disclosure an agent could not get 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?

The trigger condition and return contents are front-loaded, and the exclusion list is compact. There is mild redundancy between 'does not fetch or scrape any website' and the later 'Do not use for ... retrieving ads', which could be consolidated without losing meaning.

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?

For a two-parameter, read-only, idempotent lookup tool with an output schema, the description covers everything an agent needs: what it returns, what it will not do, and the boundary against live-checking siblings. Return value details can be left to the output 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?

Schema description coverage is 100% and both parameters are enums with their own descriptions, so the schema already carries the semantics. The description only restates that market and condition are optional filters ('optionally for a new or used vehicle'), adding no format or defaulting detail beyond what the schema supplies.

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 names a specific verb+resource ('static dealer vehicle-listing checklist') and scopes it by market (Germany, US, UK, generic) and condition, then enumerates the returned artifacts: recommended fields, photo order, title pattern and description structure. This is clearly separable from the sibling check_car_listing, since the text explicitly rules out live portal rule checking and ad retrieval.

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?

It opens with a clear triggering condition ('Use this when the user wants...') and closes with an explicit when-not list (live portal rules, retrieving ads, inspections, image/video generation). The only gap is that the alternative tool is described by function rather than named, so the agent must infer that check_car_listing is the intended destination for live-rule checks.

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