comfyui_upscale_image

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

Annotations already indicate this is a write operation (readOnlyHint=false). The description adds context about the upload prerequisite and model-determined scale factor, which is valuable. However, it does not disclose other behavioral aspects such as whether it runs asynchronously, where the output is stored, or any side effects beyond what the annotations and schema imply. With annotations present, the description offers moderate additional transparency.

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 extremely concise, consisting of three short sentences that each carry essential information: the action, the prerequisite, and the model-determined scale factor. It is front-loaded with the primary verb and contains 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?

For a tool with 3 parameters, an output schema, and annotations, the description covers the critical workflow steps: upload first, then upscale, with model selection influencing the result. Some minor gaps exist (e.g., where the result is stored, async behavior), but the schema and output schema fill most of these; the description is largely complete for a simple upscale operation.

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 input schema already covers all parameters (coverage 100%), so the baseline is 3. The description enhances parameter understanding by explaining that the upscale model determines the scale factor (e.g., RealESRGAN_x4plus = 4x) and that the image must be pre-uploaded. This goes beyond the schema descriptions, adding meaningful context.

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 opens with a specific verb+resource ('Upscale an image using a model-based upscaler'), clearly identifying the tool's function. It distinguishes this from sibling tools by emphasizing model-based upscaling and the prerequisite of prior upload, making its purpose unambiguous.

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 clearly states a key prerequisite: the image must already be uploaded via comfyui_upload_image. It also explains that the scale factor is determined by the selected model, helping the agent understand the tool's behavior. However, it does not explicitly mention alternative tools or when not to use this tool, stopping short of a 5.

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