browser_fill

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

No annotations are provided, so the description bears the full burden of behavioral disclosure. It simply says 'fill' without revealing key traits such as whether the existing value is replaced, whether DOM events are triggered, or whether the element must be visible. This is insufficient for an automation tool where such behavior affects correctness.

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 directly states the tool's action and the parameters' roles. It is front-loaded with the verb and resource, and every word adds value without unnecessary fluff.

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 fill operation, the description covers the basic action but lacks vital context: no usage guidance, no behavioral details, and no mention of event triggering. Given the sibling list includes browser_type, the absence of differentiation makes the description incomplete for reliable tool selection and invocation.

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?

With 0% schema description coverage, the description should compensate, but it largely restates the parameter names ('selector' and 'value'). The only meaningful addition is clarifying that the target element is an 'input/textarea', which is useful but minimal. The description fails to explain the semantics of the value (e.g., whether it supports special characters) or the selector format beyond naming it.

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 states a specific verb ('fill') and resource ('input/textarea identified by a CSS selector'), clearly indicating what the tool does. It does not explicitly distinguish itself from sibling tool browser_type, which could also be used for form input, so it falls short of a 5.

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 provides no guidance on when to use this tool versus alternatives like browser_type, browser_click, or browser_hover. There is no mention of prerequisites, intended form-filling scenarios, or exclusions, leaving the agent to guess the appropriate context.

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