upscale_image

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

With no annotations, the description carries the burden and does well: it discloses that all layers are scaled (Lanczos), that a new top layer is created, and which backends are supported. It stops short of stating whether a backend requires credentials/network access, what happens on backend failure, or whether the new layer becomes active.

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?

Dense but front-loaded: the core action and its side effect come first, then backend list, then the alternative-tool pointer. No filler sentences, though the backend enumeration is slightly list-like.

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 3-parameter, no-annotation, no-output-schema mutation tool, the description covers the action, its side effect, backend options, and the fallback tool. The remaining gap is the 'model' parameter and error/credential behavior, which are minor but real.

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 0%, so the description must compensate. It explains 'factor' (scaling multiplier) and 'backend' (a1111/comfyui/stability/replicate/fal), but 'model' is only alluded to via 'the model's upscaled rendering' without saying how to choose or name one, leaving one of three parameters under-specified.

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 ('AI super-resolution: scales the document by factor') plus the concrete effect of adding the upscaled rendering as a new top layer. It also explicitly distinguishes itself from the sibling scale_image, so an agent can choose between them without opening either schema.

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?

Gives an explicit routing rule: use this tool when an AI backend is available, and 'Without an AI backend use scale_image.' The alternative and the condition that selects it are both named.

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