scroll

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

Annotations only provide openWorldHint, so the description carries most of the behavioral burden. It discloses the default scroll amount (80% of viewport/container), the default container (the page), and even the return format ('scrolled y=<y>/<scrollHeight> viewport=<h>') plus detection of height changes for infinite scroll – valuable context beyond annotations.

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 compact paragraph that front-loads the core behavior and then details the two modes and output. It is dense but every sentence adds useful information; minor room for clearer separation but overall efficient.

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 (5 optional parameters, two modes, container vs page defaults, infinite scroll detection), the lack of an output schema, and minimal annotations, the description provides everything an agent needs to call it correctly: defaults, mode distinctions, and expected output format.

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 only 20% (only the tab parameter is described in schema), so the description must compensate. It does well: it explains the semantics of target, direction, amount (with default), and to (top|bottom), covering all parameters except tab, whose default is already in the schema.

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 ('Scroll') and resource ('the page or a container'), and explicitly distinguishes two modes: scrolling a target into view versus scrolling a container in a direction. This lets an agent immediately understand what the tool does without opening the schema.

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?

It clearly explains the two invocation patterns: omitting direction/to scrolls target into view, while providing direction or to makes target the scroll container. However, it doesn't name any alternative sibling tools or explicitly state when to prefer this over e.g. click or evaluate for scrolling-related tasks.

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