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 adds useful behavioral context by explaining that results include pricing per resolution and that template ids feed into generate. It does not describe ordering or pagination, but those are minor for a zero-parameter listing tool with an output schema.

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?

The description is two tight sentences with no filler. The resource and its definition are front-loaded, followed by the practical next step for using the result.

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?

The tool is simple, parameterless, read-only, and has an output schema, so the description does not need to explain return values in detail. It covers what is listed, the pricing context, and how to use the result. Minor details such as ordering or whether the list is exhaustive are left implicit.

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?

This tool has zero parameters, so there are no parameter semantics to explain. The baseline for a parameterless tool is 4, and the description appropriately focuses on the returned template data and how to use the template id.

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 uses a specific verb and resource: 'List trending video templates'. It also defines what a trend template is and states that results include total price in USD per resolution. That is enough for an agent to distinguish this from sibling tools such as list_models or estimate_cost.

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 description gives clear downstream usage: 'Use the template id in generate with { template, images }.' This tells the agent when the returned data is useful, though it does not explicitly contrast this tool with list_models or other listing tools.

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