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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint. Description adds no extra behavioral context (e.g., pagination details, result format). Without contradiction, a 3 is appropriate as it doesn't harm but adds no value beyond 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 single sentence is concise and front-loaded, but at the expense of necessary detail. It earns its place but omits critical context, making it borderline adequate.

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?

Given 5 parameters with zero schema description, no output schema, and siblings providing alternatives, the description is incomplete. Annotations are rich but insufficient to make the tool fully usable without guessing parameter semantics.

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 0% schema description coverage, the description must explain parameter meanings (ad_group_id, after, limit, order, before). It only mentions 'in an ad group', leaving four parameters (including pagination cursors and ordering) completely unexplained, failing to compensate for schema gaps.

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 'List ads in an ad group.' is specific with a clear verb ('List') and resource ('ads') within a context, effectively distinguishing from siblings like 'get_ad' (singular) and 'list_ad_groups' (different resource).

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?

No guidance on when to use this tool versus alternatives such as 'get_ad' for a single ad or other listing tools. Lacks explicit context, exclusions, or prerequisites.

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