Several ads

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), but the description adds non-obvious behavior: compact payload (specs plus one image, description truncated at 300 chars) and partial-failure semantics where a removed ad yields an `error` field instead of failing the whole call. That is meaningful context beyond the annotations, though ordering/pagination behavior is unstated.

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?

Two short sentences, zero filler, with the payload shape front-loaded and the routing hint second. Every clause earns its place.

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 usefully sketches the return shape (compact specs, one image, truncated description, `error` for removed ads), which is enough to call and interpret it. Minor gaps remain, such as whether results are returned in token order.

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?

With a single parameter at 100% schema description coverage (type, example, maxItems), the schema carries the semantics. The description only restates the batch cap of 10, adding no format or token-provenance detail beyond the schema, 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 ('Details of up to 10 ads in one call') plus the batch scope, which cleanly distinguishes it from the singular sibling dv_post. An agent knows exactly what this returns without opening the schema.

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?

'Use to read a shortlist from dv_search' names the upstream tool and the workflow condition that selects this one, which is strong routing guidance. It does not state explicit exclusions (e.g., when to prefer dv_post or dv_compare instead), so it stops short of a 5.

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