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

Annotations indicate readOnlyHint=false and destructiveHint=false, which aligns with the description's claim of producing a new cutout. The description adds the return-link detail, but does not disclose potential side effects like cost, rate limits, or whether the original image is preserved. Adequate given annotations.

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?

Two concise sentences with the primary action front-loaded and the output mentioned shortly after. No redundant words; it is efficient and easy to scan.

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 single-parameter tool with no output schema, the description is nearly complete. It states the operation, the result, and the return format. The only missing detail is the prerequisite that the image must be uploaded first, but that is already listed in the parameter description, so the description itself is sufficient.

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 parameter description in the schema already explains that imageUrl is a fal URL from fattly_upload_image (100% coverage), so baseline is 3. The parameter description adds the constraint of using a previously uploaded image, improving clarity beyond the schema's basic type definition.

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 action (removes background) and the outcome (clean cutout, returns a link). It distinguishes this tool from siblings like fattly_upscale or fattly_inpaint by being specific to background removal.

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?

No guidance on when to use this tool versus alternatives or when not to use it. There is no mention of complementary tools or conditions that would select this over others, leaving an agent to infer based solely on name and purpose.

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