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

Annotations already declare destructiveHint=true, openWorldHint=true, readOnlyHint=false, and idempotentHint=false. The description adds useful input-validity context and placement behavior, but it does not explain what destructive effect occurs or what may be overwritten when uploading and applying to a design.

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 four short sentences, front-loads the main action and accepted inputs, and contains no filler. Each sentence contributes either source semantics, required identifiers, placement guidance, or an important invalid-input constraint.

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 complex destructive upload tool with no output schema, the description covers key input sources and placement but leaves return behavior and the practical impact of the destructive flag unstated. The rich input schema and annotations carry much of the burden, but the description is still only minimally complete for safe 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 description coverage is 100%, so the baseline is 3, but the description adds meaningful semantics by naming the accepted image source alternatives and giving examples for filename, contentType, and fileType. It also explains that applyToDesign and areaId control placement.

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 a specific verb and resource: upload an image from one of several source forms. It does not explicitly distinguish this tool from close siblings such as add_image or replace_image, so it is clear but lacks sibling differentiation.

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 practical usage context, including required identifying fields and placement options, and warns that caller-local paths or bare file IDs are not downloadable artwork. However, it does not say when to use this tool instead of alternatives like add_image or replace_image, leaving selection guidance implied.

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