scroll

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

With no annotations, the description carries the behavioral disclosure burden. It explains that amount is a percentage of viewport height and that amount is ignored for top/bottom. It doesn't cover edge cases like no-overscroll or return behavior, but the output schema exists and the core behavior is well specified.

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 front-loaded with the core action, then uses a compact Args block to document parameters, and finishes with a clear alternative tool. No sentence is wasted and the structure is easy to parse.

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 two-parameter scroll tool with an output schema and no annotations, the description covers all necessary semantics: direction values, amount meaning, ignored-argument behavior, and when to use a sibling tool. There are no critical gaps.

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 is the only parameter documentation. It fully describes every enum value for direction, defines amount as a percentage of viewport height, and provides a concrete example. It also notes when amount is ignored.

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 states a specific verb and resource: 'Scroll the current page vertically.' It enumerates all four direction behaviors and explicitly contrasts with focus_on(action='scroll_to_element'), distinguishing it from a key sibling.

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 gives explicit usage guidance: 'Use focus_on(action="scroll_to_element") when the goal is to reveal a specific element rather than scroll the page by a relative amount.' This clearly identifies when to choose an alternative tool.

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