browser_fill

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

Since no annotations are provided, the description carries the full burden of behavioral disclosure. It reveals a locator-preference hierarchy but does not state whether the existing value is replaced, whether focus is needed, or whether input/change events are triggered. 'Fill input' states intent but not side effects.

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 entire description is one front-loaded sentence with no filler. The action and the priority rule are stated directly and efficiently, making every word earn its place.

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 action the description is minimally sufficient: an agent knows to provide a value and can choose a locator by priority. But it omits important behavioral context such as clearing existing content, event triggering, and applicability to textareas or contenteditable elements, and there is no output schema to fill that gap.

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 0%, so the description must compensate. It adds meaning by defining a priority order among ref, selector, and placeholder and ties ref to browser_elements. However, the required 'value' parameter is left completely undefined, and no locator syntax details are provided.

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 clear verb-resource pair ('Fill input') that distinguishes it from sibling browser tools like browser_click, browser_select, and browser_press. It does not explicitly name a competing sibling, but the action 'fill' is unambiguous enough for an agent to identify its core purpose.

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?

No guidance is given on when to choose browser_fill over alternatives such as browser_press or browser_select. The only usage hint is the parameter-preference order (ref > selector > placeholder), which is about how to invoke the tool rather than when to use it versus siblings.

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