List models

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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. With no output schema, the description usefully carries the return-content burden, disclosing that options (aspect, resolution, duration, format, audio), reference-image capacity, free-tier eligibility and default credit cost are all included — an agent knows exactly what it gets back.

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 dense sentence with the scope ('Every image, video and music model') front-loaded before the payload list. The parenthetical field enumeration is long but earns its place given the absence of an output schema.

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 parameterless, read-only catalog call with no output schema, the description covers the return payload thoroughly. It could note whether the full catalog is returned at once or whether the kind filter is required for reasonable performance, which is the only remaining gap.

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?

Only one parameter (kind) exists and schema description coverage is 100%, so the enum values and their meaning are fully documented in the schema. The description adds nothing about filtering behavior, so the baseline 3 applies.

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 the resource precisely (image, video and music models) and enumerates the facets returned, which cleanly separates it from the generate_* siblings. The verb is only implicit (the title supplies 'List'), and the sentence is framed as a return-value inventory rather than an action, so it stops 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 statement of when to call this versus alternatives, nor any prerequisite or exclusion. An agent can infer it is a discovery/catalog call to run before generate_image or generate_video, but that routing is left entirely to inference.

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