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

The description provides specific structural context for the results, mentioning the key fields (id, name, font hints). This is valuable behavioral information about the returned object that goes beyond the general read-only safety hints provided in the annotations.

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 a single, highly efficient sentence that front-loads all necessary information. It avoids filler and delivers the core functionality and scope immediately.

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-input listing tool, the description is functionally complete. It defines the action, the data being acted upon (the presets), and the contexts in which the data is relevant (the two specified themes).

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?

Since the input schema has zero parameters and 100% coverage, the description adds semantic value by defining the structure of the returned data points (id, name, font hints). Given the lack of input complexity, a 4 is appropriate.

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 specifies a clear verb ('List') and resource ('caption theme presets'), making the purpose unmistakable. It is highly granular by specifying that these presets are intended for two distinct workflows: clip_video.theme and create_music_video.theme.

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?

While the description defines exactly what the tool does, it does not provide explicit guidance on when to choose it over other sibling tools like 'list_templates.' The usage is implied to be when a user needs theme options for video creation.

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