list_widgets

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

There are no annotations, so the description carries the full burden. It discloses that the tool lists widgets and appearance options, which implies a read-only operation, but it does not explicitly state side-effect-free behavior, output format, or any limitations (e.g., whether it only returns widgets for the current canvas). Some behavioral context is added beyond the name, but not a rich disclosure.

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, concise sentence that packs in the core purpose (list widgets), scope (canvas), and additional details (fragments, theme/style/font options). There is no redundant wording or filler, making it highly efficient.

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 listing tool with no parameters and no output schema, the description is reasonably complete: it states what is listed and what extra information is included. Minor gaps exist around whether it returns all widgets globally or per canvas, and there is no explicit mention of output structure, but these are not critical given the tool's simplicity.

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 tool has zero parameters and the schema is empty with 100% coverage. The baseline for zero-parameter tools is 4. The description clarifies what is being listed, which compensates for any need to explain parameter meaning, though no parameter-specific semantics are required.

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 uses a specific verb ('List') and specifies the resource ('every widget that can be placed on a canvas'), including additional scope ('with its fragments' and 'available theme/style/font appearance options'). This clearly distinguishes it from sibling tools like list_pages or list_devices, and from get_widget_options which targets a specific widget.

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 implies usage: use this tool when you need to enumerate all widgets available for a canvas and their appearance options. However, it does not explicitly mention when not to use it or compare it to alternatives like get_widget_options, get_widget_choices, or probe_widget_data. The context is clear but exclusions are absent.

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