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

Annotations already cover readOnlyHint/destructiveHint/openWorldHint, so 'Read-only' is largely redundant, but the description adds non-annotation value: the call is 'free' (a cost trait the annotations do not express) and it discloses the shape of the returned reference data. It does not cover pagination or any caching/staleness behavior, so it falls short of a 5.

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, both load-bearing: the first defines the scope, the second defines the returned content and routes the agent to generate_*. The most decision-relevant fact (what you get and why it matters) is front-loaded with no filler.

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?

With no output schema, the description must describe what comes back, and it does — per-tier field keys, allowed values, defaults, and their effects. Combined with the explicit no-argument guidance, an agent has everything needed to call this correctly.

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 coverage is 100%, so the baseline is 3, but the description adds genuine meaning by explaining the scoping model: tiers derive from the publisher's plan rather than any title, which justifies why the sole parameter is inert. That is real semantic context beyond the schema text.

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 and resource ('List the quality/price tiers ... for every kind of media') and goes further to name exactly what each tier entry contains (field keys, allowed values, defaults). It is clearly distinguishable from the many generate_* and get_* siblings because it frames itself as the reference source for their params.

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?

Explicitly tells the agent when to consult this tool: it is 'the reference for the `params` argument of the generate_* tools'. It also pre-empts a likely mistake by stating title_id is not needed, removing an unnecessary call pattern.

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