Widget controls

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

Annotations already establish readOnlyHint=true and openWorldHint=false, but the description adds real behavioral detail beyond them: options are truncated at 30, responsive controls accept _tablet/_mobile suffixed keys, and value shapes are dictated by control type. It does not cover error behavior for an unknown widget type, so it stops short of 5.

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?

Front-loaded with the action and resource, then the when-to-call rule, then return shape detail — a sensible priority order with no filler sentences. The final value-shapes sentence is dense and runs several mappings together, which slightly hurts scanability.

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?

There is no output schema, so the description carries the burden of describing returns and does so: it lists the returned control fields and maps control types to their value shapes. Combined with the truncation cap and responsive suffix rule, an agent has everything needed to call it and interpret results.

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% and the single widgetType parameter is already documented as accepting a widget type or elType with the same examples. The description's restatement adds little beyond the schema, which is the correct baseline-3 case for a one-parameter tool.

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?

States a specific verb and resource: 'Return the control definitions (setting keys) of a widget type or elType', with concrete examples (heading, button, container) and an enumeration of returned fields. An agent can distinguish it from inspect_element and list_widgets without opening any schema.

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?

Gives an explicit trigger ('Call this before writing settings you have not seen in inspect_element') and an explicit prohibition ('never guess setting keys'), which implicitly defines the when-not case (settings already observed via inspect_element). The alternative tool is named directly.

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