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

Annotations already cover read-only, idempotent, non-destructive behavior, but the description adds genuinely new facts: the call is free of charge and the payload contains each model name plus the token price per picture ("the same number the charge takes"). Missing only things like ordering or whether availability varies by plan.

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?

One sentence, front-loaded with the purpose, then the payload contents, then the cost caveat. No filler and nothing repeated from the annotations or 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?

With no output schema, the description carries the burden of describing returns and does so precisely: model name to pass plus per-image token cost. For a zero-parameter browse tool with full annotation coverage, nothing an agent needs is absent.

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 there is nothing for the description to disambiguate; baseline 4 applies. The schema is trivially complete at 100% coverage.

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?

A specific verb ("Browse") plus a precise resource ("image-generation models available to your Switch account") with explicit tie to the consuming tool: "exactly the models generate_image accepts." That phrase also separates it from nearby list_* tools such as list_video_models, list_styles, and list_upscalers.

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 makes the use case clear by declaring the output is exactly what generate_image accepts, which implies calling this before model selection, and "Free to call" removes cost hesitation. It stops short of an explicit when/when-not instruction or naming the alternative for video models.

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