browser_fill

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

No annotations present, so description carries full burden. It mentions auto-scrolling, focusing, and working on CSP-strict sites via Chrome Debugger API. It does not specify if the field is cleared before filling, but 'fill' implies replacement. Good transparency overall.

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?

Two concise sentences front-loaded with the primary action. No waste; every sentence provides useful information.

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?

Given 2 params and no output schema, description covers purpose, usage guidelines, behavioral traits, and parameter semantics adequately. Lacks explicit mention of whether existing value is cleared or return value, but not critical for this simple tool.

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 100%, but description adds semantic value by stating selector supports CSS AND text-based selectors, and that auto-scroll/focus behavior applies. This aids agent understanding beyond the schema's type and required fields.

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?

Clearly states it fills a form input field with a value, supporting CSS and text selectors. Explicitly distinguishes from sibling tools browser_set_date and browser_set_combobox.

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?

Provides explicit when-to-use: 'Fill a form input field with a value.' Also gives clear alternatives: 'For date inputs use browser_set_date, for autocomplete/combobox use browser_set_combobox.'

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