click_at

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

With no annotations, the description fully carries the burden. It discloses it uses a 'real mouse event', returns 'post-action page_state', and notes it is 'less reliable' than the selector-based click. It does not discuss rate limits or permissions, but for a clicking action this is adequate transparency.

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 two sentences, front-loaded with the primary action, then usage guidelines. Every sentence adds value with no wasted words. It is highly concise and well-structured.

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 no output schema, the description mentions 'post-action page_state' which is sufficient for a click tool. It also references sibling tools. It might implicitly assume coordinates are within viewport, but overall it is complete for the tool's complexity.

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 the description adds significant extra context: for 'widen' it explains default and full-page diff effect; for 'x' and 'y' it explains how to obtain them via getBoundingClientRect. This goes well beyond the schema definitions.

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 explicitly states 'Click at specific viewport coordinates (x,y) using a real mouse event' and distinguishes itself from the sibling 'click' tool by specifying exclusive use for elements without stable CSS selectors like canvas, maps, SVG regions. It provides a clear verb-resource pair and differentiates use cases.

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 gives explicit when-to-use ('exclusively for elements without stable CSS selectors') and when-not-to-use ('prefer the selector-based click tool for normal DOM elements'), along with instructions for obtaining coordinates via execute_js with getBoundingClientRect.

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