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

The description adds useful behavior beyond the annotations: credit cost depends on source resolution × factor, and it returns the upscaled image URL. Annotations already indicate non-readonly, non-idempotent, non-destructive, and open-world, and the description does not contradict them. It could mention side effects or limitations, but the cost model is valuable.

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?

Three concise, front-loaded sentences: purpose, usage, and cost/return. No filler or redundancy.

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 only 2 simple parameters and no output schema, the description fully covers inputs, output, and cost behavior. It is complete for the tool's complexity and provides enough context for correct invocation.

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. The description adds extra meaning by explaining that credit cost is a function of resolution and factor, which helps choose parameters. It also reiterates the need for a public URL, aligning with the schema's format.

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 starts with a specific verb 'Upscales' and a clear resource 'source image', also naming the technology 'Topaz's high-fidelity upscaler'. This clearly distinguishes it from sibling tools like aetherwave_upscale_video or aetherwave_edit_image.

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?

It gives clear instruction to pass a public imageUrl and upscaleFactor, and provides cost guidance based on resolution and factor. It doesn't explicitly mention alternatives or exclusions, but the image-specific language and sibling tool names make the intended use clear.

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