Check Element

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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is known. The description adds no additional behavioral context, such as whether toggling fires events, requires a loaded page, or has side effects. It neither contradicts the annotations nor enriches them with useful extra detail.

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 sentence, front-loaded with the action, and contains no filler. Every word earns its place, making it highly concise and well-structured.

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 state-setting tool, the description is adequate, especially with annotations and an output schema present. However, it does not mention prerequisites like needing a page loaded or whether the element must be visible, but given the simplicity, this is a minor gap. The description leaves room for implied assumptions about context.

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 75% (moderate), and the description contributes no parameter semantics beyond what the schema already provides. The schema clearly describes 'by_js' and 'checked,' while 'selector' and 'timeout' are mostly self-explanatory. Baseline of 3 is appropriate since the schema does the heavy lifting.

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 tool's function: 'Set a checkbox or radio element to checked/unchecked.' This is a specific verb ('Set') + resource ('checkbox or radio element') + action ('checked/unchecked'), which distinguishes it from sibling tools like element_click (clicks) or element_select (selects options).

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 when you need to change the checked state of a checkbox or radio. However, it provides no explicit exclusions or alternatives, such as 'prefer this over element_click for checkboxes.' There is no guidance on when not to use it or how it compares to similar tools.

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