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

Annotations already declare destructiveHint=true and related traits. The description adds meaningful behavioral context beyond that: it preserves the existing box by default unless a new placement is requested, and it overwrites current image content. It does not discuss reversibility or permissions, but adds solid value over the 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?

Three sentences, front-loaded with the core action and followed by the overwrite warning and prerequisite. No wasted words.

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 the essential action, destructive behavior, default box preservation, and a prerequisite for target/print-area resolution. It is reasonably complete for a mutation tool without an output schema, though it could mention sibling alternatives or restoration behavior.

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 100%, so the input schema already documents parameters thoroughly. The description adds a little semantic context about image-box preservation and optional new placement, but not enough to exceed the baseline for high schema coverage.

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 states a specific verb and resource: replace the target's current artwork using an uploaded image. The overwrite language ('This overwrites the selected image content') implicitly distinguishes it from add_image, though it does not explicitly name that sibling.

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 provides a useful prerequisite ('Resolve the target and print area first') but does not say when to use this versus add_image, upload_image, or restore_original_image. Usage is implied by the overwrite semantics rather than explicitly guided.

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