scroll

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

The description adds the scroll direction convention (dy negative/positive) and practical guidance about using large values for meaningful scroll distance. The annotation openWorldHint=true suggests this operates in an open context, and the description aligns with no contradictions. It doesn't describe return values or touch behavior, but the annotations cover the safety profile.

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 concise sentences with zero waste. The direction semantics and example values are front-loaded. It could arguably be more concise by removing redundant direction restatement, but the examples add practical value for parameter tuning.

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 there is an output schema, the return value is covered externally. The description covers the scroll direction convention, provides magnitude guidance, and the schema handles all parameters. It provides adequate context for a positioning tool, though it could mention that coordinates refer to the screen coordinate system.

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 100%, so the schema documents all 5 parameters including dx/dy direction conventions and x/y coordinates. The description adds the practical guidance about using large values (e.g., -400, 500), which is additive. The serial parameter has clear schema documentation, so no further detail is needed.

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 clearly states 'Scroll at the specified position' and provides specific direction semantics (negative dy = scroll up, positive dy = scroll down). It is immediately distinguishable from siblings like scroll_to_element, which scrolls to a target element rather than to a position.

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 implies usage by showing how to trigger scroll directions with examples like -400 and 500. However, it doesn't explicitly state when to use this tool vs scroll_to_element or other scroll alternatives, and doesn't mention prerequisites like starting a session or having a device connected.

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