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

Annotations already indicate this is a write operation that is not destructive. The description adds a useful behavioral detail: position, width, and height are automatically defaulted. It does not disclose return values or side effects, but the output schema and annotations ease that burden.

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 a single, well-structured sentence that front-loads the action and object, then adds one relevant default-behavior note. There is no filler or repetition of schema content.

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 simple create operation, the description is minimally adequate: the action is clear and all parameters are documented in the schema. However, it does not help an agent distinguish when to choose this widget type over sibling add_*_widget tools, and it does not clarify what the created button widget looks like or how it is returned.

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%, and each parameter already has a meaningful description with source hints like 'from list_pages' and 'from list_reports'. The tool description adds no additional parameter-level meaning beyond noting that layout properties not present in the schema use defaults.

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 ('Add') and the resource ('a button widget to a page'). It does not explicitly differentiate from the many sibling add_*_widget tools, but the widget type is named directly and the scope is clear.

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?

There is no guidance on when to use this tool versus alternatives such as add_text_widget, add_image_widget, or update_button_widget. The note about defaults is mild usage information, but it does not help an agent choose among the closely related add_*_widget siblings.

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