direct_list_ad_extensions

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the description's "Read-only" merely restates structured data. It adds nothing about pagination behavior (limit defaults to 500), response size, or rate limits for a listing tool, so no new behavioral context is supplied.

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 description is very short and front-loads the resource, with the sibling pointer kept brief. The parenthetical "(Id, Type, Status, text)" is of questionable value given an output schema exists and its meaning is unclear, but overall there is no padding.

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?

The output schema covers return values, so those needn't be explained, but for a list tool with three entirely undocumented parameters the agent is left without knowing the default page size or how to filter by ids. Combined with no usage context, the definition is under-specified for correct invocation.

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 0% for all three parameters (ids, limit, offset), and the description does not compensate — it never explains that ids filters to specific extensions or how limit/offset paginate. The parenthetical field list reads like output fields rather than the actual arguments, adding no real meaning.

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 the resource (callout extensions) and explicitly routes sitelinks queries to the sibling `direct_list_sitelinks`, so the agent can distinguish the two. The listing verb itself lives only in the tool name, and the parenthetical "(Id, Type, Status, text)" is ambiguous about whether those are return fields or filters, keeping it short of a 5.

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?

"Read-only" plus the sitelinks pointer imply this is a query tool for callout extensions and give one alternative, but there is no explicit when-to-use, no condition for choosing this over other direct_list_* tools, and no mention of prerequisites. Usage is implied rather than stated.

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