page_click_at

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

With no annotations provided, the description carries the full burden and does solid work: it states the failure condition for out-of-viewport coordinates, and it discloses the post-click report (network/console/url delta). It doesn't fully document every side effect or prerequisite, but the essential behavioral traits are covered.

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?

Three sentences, no fluff, and the most important fact — coordinate space alignment with screenshots — is front-loaded. Every sentence earns its place and the structure makes the tool's mental model immediately clear.

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 6-parameter tool with no output schema and no annotations, the description covers the critical context: coordinate system, failure mode, and return delta. It doesn't spell out coordinate origin or interaction with existing page state, but the required information to call the tool correctly is present.

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 only 33%, so the description must compensate. It does add crucial meaning for x and y by defining the coordinate space and its alignment with screenshots. However, button, sessionId, and the exact meaning of clicks/waitMs beyond the schema text receive little or no additional semantic help.

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 uses a specific verb ('Click') and resource ('raw viewport coordinate in CSS px'), and clearly scopes the operation to coordinate-based clicking rather than DOM-targeted clicking. It distinguishes itself from sibling tools like page_click by explicitly stating 'No DOM target needed (canvas/WebGL)'.

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 makes the appropriate context clear: use this when you have raw pixel coordinates from page_screenshot or page_look, and when no DOM target exists. It does not explicitly name an alternative for DOM-based clicks, though the 'No DOM target needed' phrasing implies page_click would be the alternative.

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