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

With annotations already covering readOnly/openWorld safety, the description adds real operational context: results are limited to the first server-rendered page (~25 ads), total matches live in `raw.totalMatches`, a filter is mandatory, and each call costs 1 credit. Cost and pagination limits are exactly the traits an agent needs before invoking.

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?

Front-loaded with purpose and scope, then cost and return-shape notes; every sentence carries information. The 'Pass `company`, `keyword`, or both' instruction appears twice, a minor redundancy that keeps it from a 5.

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?

No output schema exists, and the description compensates by describing the return shape (~25 ads, total in `raw.totalMatches`). For a 6-parameter search tool the date/country filters are left unexplained in prose, but the essential call-correctly information is present.

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 83%, so the schema already documents most parameters. The description clarifies that `company` accepts a page slug or numeric id and that `keyword` matches ad copy, but leaves `start_date`, `end_date`, `countries`, and `cache_max_age` entirely to the schema, adding only marginal meaning beyond it.

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 (search) and resource (LinkedIn's public Ad Library) plus its two filtering axes, advertiser and keyword. An agent can immediately distinguish it from the sibling single-ad tool linkedin_ad and from other networks' ad-library searches.

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?

Gives an explicit usage constraint: 'Pass `company`, `keyword`, or both. The Ad Library will not return an unfiltered archive,' which tells the agent not to call it with no filters. It does not explicitly name a sibling alternative (e.g., linkedin_ad for a single known ad), so it stops short of full routing guidance.

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