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

Annotations already declare the safety profile (readOnlyHint=true, destructiveHint=false), so the bar is lower. The description adds genuine value beyond them: it clarifies the returned entities are ad-creation templates and discloses conditional return behavior (product_link appears per row when product_ref is used).

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?

Three tight sentences, front-loaded with purpose before the disambiguation and the parameter note. No filler; every clause conveys 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?

For a zero-required-param list tool with no output schema, the description covers purpose, disambiguation, and the only substantive optional parameter's effect. The undocumented connection_context is a minor gap given its conventional role.

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 carry the load. It explains product_ref well, including its conditional effect and the product_link field it surfaces, but says nothing about connection_context. One of two parameters is meaningfully documented, so this is adequate but incomplete.

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+resource ('List saved reusable Google ad templates') and preempts a likely confusion by noting these are ad-creation templates, not an insights breakdown. It does not name its closest siblings (google_ads_template_save/update/delete), but the resource is unambiguous.

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?

Implied usage through the product_ref note ('limits the list to one product card when product cards are enabled'), but there is no explicit when-to-use versus the template mutation siblings or google_ads_product_cards_list. An agent can infer the read-only listing role, but nothing routes it among alternatives.

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