browser_highlight

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

With no annotations, the description carries the burden and it delivers: 'Does not affect page behavior' is a meaningful safety guarantee, and 'persistent' discloses the overlay's lifetime behavior. It could mention cleanup or timeout, but the core non-destructive nature is explicit.

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, each earning its place: the action, the use case, and the side-effect guarantee. The key functional constraint (selector or ref) is front-loaded with the verb.

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 visual overlay tool this is largely complete: the agent knows what to target, why to use it, and that it is safe. It stops short of describing return values or timeout behavior, but no output schema exists and the core invocation constraints are covered by the schema.

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 83%, so the schema already documents most parameters. The description adds no new parameter-level detail beyond noting CSS selector/aria ref, which the schema already states; the undocumented 'timeout' parameter is not explained in the description either.

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-resource pair ('Draw a persistent highlight overlay') and clarifies the target is an element identified by CSS selector or aria ref. It also states the intended purpose (screenshots/video focus), making it easy to distinguish from siblings like browser_hide_highlight and browser_take_screenshot.

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?

It explicitly says the tool is useful for screenshots and video recording to show agent focus, giving clear when-to-use context. It does not state when not to use it or name alternatives explicitly, but the inverse browser_hide_highlight is implied by 'persistent' and the label-as-key parameter.

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