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

Annotations already declare the tool as read-only, idempotent, and non-destructive, so the safety profile is covered. The description adds that it includes a credit table and lists everything a request can choose from, which is useful context about the return content. It doesn't describe return format, pagination, or other behavioral details, but with annotations present, this is adequate.

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 sentences, front-loaded with the list of contents and followed by the use case. Every phrase earns its place, with no redundant or vague statements.

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 no-parameter catalog tool with no output schema, the description sufficiently summarizes the return content and when to use it. It could go further by describing the structure of the response (e.g., grouped by type), but given the simplicity and annotation coverage, it is nearly complete.

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?

The tool takes zero parameters, so the baseline score is 4. The description doesn't need to explain parameter semantics, and the empty schema is fully self-explanatory.

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 clearly enumerates what the tool returns: video types, Look categories, background sources, formats, and credit prices. It is a catalog of selectable options, which is distinct from sibling tools like get_look or list_videos. It doesn't explicitly name a sibling it is not, but the aggregate nature is evident.

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 second sentence gives clear context: 'Use it to pick a category or source and to explain prices.' This tells the agent when to call it. However, it lacks explicit exclusions or alternatives (e.g., 'not for fetching details, use get_look instead'), so it falls short of a 5.

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