upscale_image

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

No annotations are present, so the description carries the full burden. It discloses the underlying model, input constraints, and a key side effect (higher detail may deviate from the original). It lacks info on postconditions like whether the original is modified, but the output schema covers return format.

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?

The description is compact and front-loaded with the main purpose, followed by a succinct parameter breakdown. No fluff or redundant information.

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?

The description covers all three parameters with defaults and constraints, includes behavioral context, and benefits from an output schema. It is complete for a straightforward tool, despite not explicitly naming alternatives.

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 description coverage is 0%, and the description fully compensates by explaining each parameter's type, default, allowed values, and constraints (e.g., image_url format/size, resolution choices, detail range and trade-off).

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 clearly states the tool's function: enlarging and enhancing image detail to 4K/8K resolution. The specific model name and parameter list further clarify its role, distinguishing it from sibling generation tools like generate_image or image_to_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?

The description provides clear context for when to use the tool (whenever image upscaling to 4K/8K is needed). It does not explicitly compare to alternatives, but the purpose is unambiguous enough for an agent to select this tool correctly.

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