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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description still adds real value by disclosing that the returned template is 'unsaved' (non-persistent) and that a 'source fingerprint' accompanies it, which an agent would not know from annotations or schema. It stops short of covering auth or rate-limit behavior.

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 front-loaded sentence with no filler; the purpose and the nature of the return are stated immediately. It is efficient, though it is arguably terse rather than optimally sized given the untold return structure.

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 description is the only place to explain the returned artifact, yet 'normalized template preview' and 'source fingerprint' are left unexplained. Combined with a five-parameter schema at 20% coverage, an agent has enough to identify the tool but not enough to predict or use its output confidently.

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 20% (just the customer_id format is documented), and there are five parameters including three required identifiers. The description never explains ad_id, ad_group_id, name, or connection_context semantics, so it fails to compensate for the documentation gap as the low coverage demands.

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 names a specific verb and resource ('Read one owned responsive search ad') and specifies the output, 'an unsaved normalized template preview plus a source fingerprint'. That is materially more precise than the name alone. It does not, however, differentiate itself from close siblings like google_ads_templates_list or google_ads_responsive_search_ad_create_prepare, so it falls 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?

There is no explicit when-to-use or when-not-to-use guidance, and no alternative is named. An agent must infer from the name and the crowded template/responsive-search-ad sibling set when reverse-engineering an existing ad is preferable to listing, saving, or creating a template. Nothing in the text resolves that ambiguity.

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