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

Beyond the annotations (write, open-world, non-destructive), the description discloses two genuinely useful traits: a newly created ad group is created paused, and images must be supplied as https URLs. It omits whether the ad itself is created paused, permission requirements, and any validation/rate-limit behavior, so it is helpful but not complete.

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?

Two tight sentences, with the primary action and its two modes front-loaded and the image-format constraint appended. Nothing is redundant or padded.

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?

For a 13-parameter mutation tool with no output schema and no annotation explanation of return values, the description covers the mode split and image constraints but leaves the majority of required creative fields unexplained and says nothing about outcome. Adequate but clearly incomplete.

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 only 23%, so the description carries real weight: it clarifies that landscape_images and square_images are https URLs and hints at the ad_group_id vs campaign_id+ad_group_name split. However, required fields such as headlines, long_headline, descriptions, and business_name get no semantic guidance, and limits/logos are unaddressed, leaving a substantial gap.

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 (add a responsive display ad) and covers both modes: attaching to an existing Display ad group or creating a new ad group in a Display campaign. The ad type (responsive display) is named, which separates it from generic ad creators, but no sibling tool is named explicitly to sharpen the boundary with google_ads_create_ad or google_ads_update_display_ad.

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?

The two operational modes are described (existing ad group vs new ad group in a campaign), which implies when each path applies, but the description never states how to choose between them or when to prefer the dedicated google_ads_create_ad_group / google_ads_update_display_ad tools instead. The mode-selection logic is only partially recoverable from the campaign_id schema note.

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