Ad Details

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

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true) by disclosing credit consumption, the mandatory confirm=true, cache-vs-live behavior, that optional fields are null when unpublished, and that text extraction uses OCR so accuracy varies. The read-like POST/no-social-publish clarification reconciles the non-read-only annotation with the actual effect.

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 the core purpose, then layers conditional details (political-ad spend/targeting, nullability, return structure, OCR caveat) in an orderly sequence. Slightly dense and field-list-heavy, but nearly every clause carries information an agent needs.

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 available, the description compensates by describing the return shape in detail: spend currency/amount bounds, targeting criteria with Google criterion IDs, creativeRegions, regionStats per-region impressions, and variations (destinationUrl, headline, description, imageUrl). That is sufficient for a 4-parameter tool.

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 100%, so the schema already documents url, account, confirm, and cache_max_age. The description reinforces confirm=true and credit cost but adds no syntax or format 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 (retrieves) and resource (detailed information about a specific Google ad), then enumerates the concrete fields returned (advertiserId, creativeId, format, firstShown, lastShown, overallImpressions). An agent can distinguish this from google_ad_library_company_ads, which lists a company's ads rather than one ad's details.

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?

Provides prerequisites rather than routing guidance: it warns that the call consumes paid credits, requires confirm=true, and notes cache_max_age behavior. However it never states when to use this over sibling advertiser/company/transcript tools or what to do if the ad URL is unknown, so selection guidance is only implied.

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