Browser Mouse Move

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

With no annotations at all, the description carries the full burden of behavioral disclosure. It does not state whether the movement triggers hover events, what happens for out-of-viewport coordinates, whether movement is instant or animated, or whether a valid session is required. This is a significant gap for a tool that manipulates the browser UI.

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 a single short sentence with no filler, and the key concept 'viewport coordinates' is front-loaded. It is efficient, though slightly too terse to carry the behavioral weight needed given the lack of annotations and parameter documentation.

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 tool with three required parameters, no annotations, and no output schema, the description omits too much: sessionId is unexplained, coordinate bounds are unknown, and side effects like hover-event firing are not disclosed. An agent can guess the basic action but lacks enough context to invoke it reliably in all cases.

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%, so the description must compensate. 'Viewport coordinates' gives minimal meaning to x and y, but the description never explains their units or origin, and sessionId is entirely unaddressed. The hint is better than nothing but leaves two of the three required parameters semantically empty.

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 and resource: 'Move the mouse to viewport coordinates.' This clearly distinguishes it from click-style siblings like browser_mouse_click_xy, since it only moves without clicking, and from element-based actions like browser_hover because it targets raw coordinates. It does not explicitly name a sibling, but the intent is unambiguous.

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?

No guidance is given about when to choose this tool over browser_mouse_click_xy, browser_hover, or browser_drag. The description implies it is for moving the cursor without clicking, but it never states this or mentions any exclusions or prerequisites such as an active session.

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