Choose

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

Annotations already declare readOnlyHint=false and openWorldHint=true, so the mutation/open-world profile is covered. The description adds the return behavior ('answers with what changed on screen'), which is genuinely useful, but says nothing about failure modes (option not found, lazy-loaded options) or whether the dropdown must be closed first. With annotations doing the safety work, a 3 fits.

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 short sentences: what it does, when not to use it, and what it returns. Front-loaded with the core action and zero filler.

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 2-param tool with no output schema, the description covers the action, the alternative path, and the return shape ('what changed on screen'). Only minor gaps remain around error/edge behavior for missing or virtualized options.

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 both params (ref, option) are fully documented in the schema, including the frame-qualified ref format and 'exactly as shown'. The description only restates that the option is matched by visible text, adding little beyond the schema. Baseline 3 applies.

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 (Choose) and resource (an option of a native dropdown, combobox, listbox), and explicitly scopes it to native widgets, distinguishing it from the button/list sibling path. An agent can tell exactly what this does without opening the 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 the positive case (native dropdown by ref + visible text) and the exclusion with a named alternative: 'For one built from buttons and lists, open it and use browser_click.' That is an explicit when-not plus a redirect to a sibling.

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