fill_element

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

With no annotations, the description carries the burden of behavioral disclosure. It adds the useful behavioral trait that the selector is 'automatically healed' if it fails, which goes beyond the schema. However, it does not mention whether it types like a user, clears existing values, triggers events, or requires focused/visible elements, leaving significant behavioral ambiguity.

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 exceptionally concise: two short sentences with no fluff. The core purpose is front-loaded in the first sentence, and the second sentence adds meaningful behavior. Every word earns 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?

Despite having an output schema, the context is thin. The description tells what the tool does and one behavioral nuance, but it omits important details: selector format, whether it replaces or appends text, and any page-level constraints. For a two-parameter tool it is adequate but has clear gaps.

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 0%, so the description must compensate. It implications that 'selector' refers to the form/input element and 'value' is the value to fill, but it does not explain selector syntax or value subtlety. It provides basic meaning above the raw schema but does not fully compensate for the missing parameter descriptions.

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 and resource: 'Fill a form/input element with a value.' It clearly describes what the tool does and is distinct from siblings like click_element and get_content. However, it does not explicitly name any sibling or contrast itself with them, so it stops short of full differentiation.

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 usage guidance is provided. The description does not say when to use fill_element over click_element or evaluate_js, nor does it mention prerequisites such as element visibility or page readiness. The context for when this tool is appropriate must be inferred from its name and first sentence.

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