fill

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

With no annotations, the description carries the full behavioral burden and falls short: it does not say whether existing text is cleared or appended, whether input events are dispatched, whether the field must be visible/enabled, or what happens on timeout. Only the barest mutation semantics are conveyed.

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?

One short, front-loaded sentence with no filler. It is efficient, though the brevity reflects under-specification rather than disciplined concision.

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 mutation tool with no annotations, no output schema, and four undocumented parameters, this description is far too thin. It gives an agent no basis for handling clearing behavior, event dispatch, timeouts, or session context.

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% across 4 parameters, and the description adds no parameter meaning beyond implying that 'value' is the text and 'selector' identifies the field. sessionId and timeout are entirely unexplained in both schema and description.

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?

States a specific verb (fill) and resource (input field) with the content type (text), so the core action is unambiguous. However, it does nothing to distinguish itself from siblings like click, select, or interact_accessible_node, which also perform field-level interactions. The purpose is understandable but minimally delineated.

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?

There is no guidance on when to use fill versus select, click, or interact_accessible_node, nor any prerequisites such as the element being visible or focusable. The agent must infer all usage context from the name alone.

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