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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description's 'Read only; no spend' largely restates that, though 'no spend' adds a useful cost dimension. It reveals nothing about what the public library returns or rate/query constraints.

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?

Short and front-loaded with the core purpose. The resource-URI 'Fields' sentence is cryptic and earns little of its space, but overall there is minimal waste.

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 six params, a nested filter object at 50% description coverage, and no output schema, the description should explain the search filters and what results look like. Instead it provides only a URI pointer, leaving the agent without the detail needed to invoke it confidently.

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 coverage is only 50% and the schema leaves the nested 'parameters' object almost entirely undocumented (q, limit, adType, countries, etc. have no descriptions). The description compensates only with a cryptic pointer 'Fields: soclo://tools/...' and adds no meaning about how these filters behave.

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 ("Search the public Ad Library"), which clearly separates it from the owned-account ad tools that dominate the sibling list. It does not name any sibling to contrast against, but the 'public library' scope is distinctive enough for an agent to select it.

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?

There is no guidance on when to use this versus the many other ad-search siblings (search_ad_interests, search_ad_targeting) or owned-ad listing tools. It only notes 'Read only; no spend', which is a safety note, not usage direction.

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