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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds useful content disclosure (what is listed: models, prices, dedicated processing availability), but says nothing about freshness, rate limits, or pagination.

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, front-loaded sentence with zero filler. Every clause adds a distinct piece of information about what the tool returns.

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 simple read-only list tool with no nested objects and no output schema, the description adequately conveys the return content and safety is covered by annotations. The only real gap is the unexplained includeUnavailable parameter, which is a minor but noticeable omission.

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?

There is one parameter, includeUnavailable, with 0% schema description coverage, and the description never mentions it. The phrase 'dedicated processing availability' gestures at availability but does not explain whether unavailable models are hidden by default or how to include them, so it fails to compensate for the coverage gap.

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 (List) and resource (image models) plus the fields returned: prices and dedicated processing availability. This clearly separates it from action-oriented siblings like generate_image, upscale_image, and derive_image, though it never names them explicitly.

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 offers no when-to-use guidance, no prerequisites, and no mention of alternatives. An agent can infer this is a discovery/pricing lookup tool, but nothing in the text confirms that role or rules out other siblings.

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