scroll

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

With no annotations, the description carries the full behavioral burden. It thoroughly explains direction semantics, the meaning of amount as a percentage of viewport height, and notes that amount is ignored for 'top' and 'bottom'. However, it does not mention edge cases such as bounds, invalid amounts, or behavior when the page cannot scroll further.

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 well-structured: a one-line purpose, a compact argument list, and a final routing note. Every sentence adds value, and the most important scoping information appears first. There is no redundant or filler content.

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 the tool's moderate complexity, the description covers the action, all parameter semantics, special cases, and the relevant sibling alternative. An output schema is present, so return-value documentation is not required. An agent has enough context to use this tool 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?

The input schema has 0% description coverage, so the description must compensate. It fully explains both parameters: each 'direction' value is defined, and 'amount' is described as a percentage of viewport height with a concrete example. This exceeds the schema's bare enum/default information.

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 and resource: 'Scroll the current page vertically.' It further differentiates itself from the sibling tool by explaining that focus_on(action="scroll_to_element") is for revealing a specific element, whereas this tool handles page scrolling.

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 states when to prefer an alternative: '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 gives clear, actionable routing guidance with no ambiguity.

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