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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered structurally. The description adds that policy approval status and responsive-search-ad copy are included, which is genuinely useful scope information, but it says nothing about pagination via the limit cap, multi-account fan-out when a folder is used, or what 'performance for the period' contains.

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?

A single compact sentence with no filler, and the field enumeration is front-loaded. It is a verbless fragment, but nothing in it is wasted.

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, the field list is valuable, but for a 7-parameter reporting tool spanning folder/account/date/campaign scoping, the description should say how ads are selected and whether results aggregate across accounts. It is adequate but leaves real gaps given the tool's complexity.

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 86%, so the schema already explains limit, folder vs. account, date_range, custom dates, and campaign_id; the baseline of 3 applies. The description only echoes the period concept with 'for the period' and adds no syntax, defaults, or interaction rules beyond the schema.

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 is a noun phrase listing returned fields (type, status, policy approval status, final URL, headlines/descriptions, performance) rather than a verb+resource statement like 'List ads'. Combined with the title it is inferable as a retrieval tool, but there is no explicit statement of the action and no differentiation from close siblings such as google_ads_ad_performance, google_ads_assets, or google_ads_policy_issues.

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 when-to-use guidance at all: nothing says whether to pick this over google_ads_ad_performance for performance numbers or over google_ads_policy_issues for approval problems. No prerequisites or exclusions are stated.

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