fill_element

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states the core action (typing text) and does not mention that the element is cleared before typing by default, that Enter can be pressed, that the tool waits for the element up to timeoutMs, or any error behavior. These details exist in the parameter descriptions but not in the tool-level description.

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 with no filler or redundant information. The action and target are front-loaded, and every word adds meaning. It is an example of efficient, concise specification.

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?

The tool has six parameters with meaningful defaults (e.g., clearBefore=true, pressEnter=false, timeoutMs=10000) and no annotations to convey side effects or safety behavior. The description alone leaves important behavioral context implicit, though the schema fills many gaps. The combined context is sufficient for a basic fill action, but the tool-level description is not fully complete on its own.

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 100%, and every parameter includes its own description in the input schema. The tool description itself adds no parameter-specific meaning, which is acceptable because the schema already documents each parameter fully. Baseline 3 is appropriate.

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 ('Type') and a specific resource ('an input or textarea element'), making the tool's function immediately clear. It also differentiates itself from sibling tools like press_key (which types anywhere) and clear_element (which only clears), so an agent can distinguish it without opening the schema.

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 the tool is intended for filling input and textarea elements, which gives some contextual signal. However, it does not explicitly mention when to prefer this tool over alternatives, such as press_key or select_dropdown, nor does it state any exclusions or preconditions.

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