Click at coordinates

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

The description reveals that coordinate clicks are not robust against layout shifts, use real CDP events with the same scripted fallback and 10s bound as `click`, and that coordinates are in CSS pixels ignoring device pixel ratio. These details extend well beyond the sparse annotations and provide critical execution context.

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 well-structured in four tight paragraphs, each addressing a specific aspect: core function, alternative usage, coordinate constraints, and behavioral equivalence. No redundant or filler sentences, and the most important information is front-loaded.

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 simple click action, the description covers when to use it, how it differs from `click`, coordinate system details, viewport requirements, and event behavior. With an output schema present, this is fully complete for an agent to invoke correctly without additional assumptions.

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?

The schema already describes all 4 parameters (100% coverage), so baseline is 3. The description adds meaningful semantics for x/y by stating they are in CSS pixels, viewport-relative, and matching emulate/resize_page, plus the viewport constraint. These additions clarify the coordinate system beyond the schema, though other parameters are not additionally addressed.

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 opens with 'Click a raw viewport coordinate instead of an element,' clearly stating the verb, resource, and distinguishing from `click` which targets elements. It further clarifies use cases for surfaces without addressable elements, such as canvases, maps, and video players.

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?

It explicitly instructs to use `click` with a uid when the target appears in a snapshot, and reserves coordinates for non-element surfaces. It also provides a prerequisite: scroll into view if the point is outside the viewport, naming `scroll_page` and `scroll_to_selector` as alternatives.

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