scroll

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

No annotations are provided, so the description carries the full behavioral burden. It discloses that it 'returns before/after scroll position, pageHeight, and nearBottom' and reveals a key behavioral nuance about virtualized lists skipping content. It does not explicitly state side effects or whether it's read-only, but for a scroll tool this is largely inferable. It adds meaningful behavioral context beyond the bare operation.

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 front-loads the core purpose in the first sentence, then uses a compressed but readable enumeration of modes, and ends with a single practical caveat about virtualized lists. Every sentence earns its place; there is no filler or repetition. Appropriately sized for a 7-parameter multi-mode tool.

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?

Despite having 7 parameters and no output schema, the description is remarkably complete: it explains all four invocation modes, discloses return values (before/after scroll position, pageHeight, nearBottom), and provides guidance on the trickiest scenario (virtualized lists). Given the tool's moderate complexity and lack of annotations/output schema, this is thorough enough for an agent to select and invoke correctly.

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%, so the baseline is 3, but the description adds real value beyond the schema by grouping parameters into distinct usage modes (node_id for scroll containers, x+y for wheel events, selector for scrollIntoView). It also clarifies that scrollY is the primary delta with a default of 600, contextualizing the parameter semantics beyond raw field descriptions.

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 a specific verb+resource: 'Scroll the active tab by a delta (positive scrollY scrolls down).' It then enumerates four distinct modes (page scroll, node_id container, x+y wheel-at-point, selector scrollIntoView), clearly distinguishing this scrolling tool from siblings like goto, click, and eval_js. The purpose is unambiguous and well-scoped.

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 explicitly lists when to use each mode: 'pass node_id to scroll inside a specific scroll container, x+y to send a mouse wheel at a viewport point, or selector to scrollIntoView a specific element.' It also provides proactive guidance on virtualized lists, recommending small steps and extraction between steps. This is explicit, actionable usage guidance superior to most tool descriptions.

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