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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=true. The description adds real value beyond that: asset-count constraints (3-15 headlines, 2-4 descriptions), which fields are required, and the dry-run preview semantics of confirm=false.

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, front-loaded with the action, then the required asset shape, then the confirm workflow. No filler; every clause adds operational information.

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 mutation tool with a rich annotation set and an output schema (which removes any need to describe return values), the description covers the essential creative constraints and the preview/apply behavior. The only real gap is the uncharted account-scoping parameters and any permission prerequisites.

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 0%, so the description must compensate, and it does for the core creative parameters: headline/description count limits (which the schema does not express as minItems/maxItems), final_url required, path1/path2 optional display paths, and confirm as a preview flag. It leaves account_id, ad_group_id, and customer_id semantics undocumented, which keeps it out of 5 territory.

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 ("Creates a Responsive Search Ad (RSA)") and immediately enumerates the required asset shape, so an agent knows exactly what entity is produced. It does not, however, explicitly differentiate itself from the sibling create_responsive_search_ad (the Google counterpart) beyond the tool name/title, so it falls just short of a 5.

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 confirm=false preview / confirm=true apply workflow is genuinely useful usage guidance and implies a safe two-step pattern. However, there is no statement of prerequisites (an existing ad group/account) or when to prefer update_microsoft_responsive_search_ad over creating a new ad.

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