scroll_page

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

Annotations include destructiveHint: true, and the description aligns by implying the scroll changes the page state and temporarily affects the viewport. The description also discloses that it reports the new position, which is useful behavior. It doesn't delve into side effects like triggering scroll events or lazy loading, but that's not required given the annotation. The description adds value by explaining the scan_page interaction and the default behavior, which annotations don't cover.

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 concise and well-structured. The first sentence states the core function (scroll and report position). The second sentence provides the critical usage note about scan_page's limitation, which is essential for correct usage. The third sentence lists the target options and defaults. There is no fluff; every sentence provides necessary information.

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?

The description is complete for the complexity level. It covers the action, the interaction with a sibling, parameter semantics, and defaults. An output schema exists, so return value details are not needed. The tool has only 3 parameters, all optional, and the description sufficiently explains them. No critical information is missing for an agent to invoke it 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 description coverage is 0%, so the description must carry the meaning. It does so by explaining the 'to' parameter's allowed values ('bottom', 'top', pixel offset, CSS selector) and the timeout default (15 seconds). The session_id parameter is not described, but it's a common context parameter, and the lack of specific meaning is acceptable given the description's focus. Overall, the description compensates well for the schema's sparse documentation.

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 the tool's purpose: scroll the page and report the new position. It also differentiates itself from sibling scan_page by explaining the 5000px limitation and the need to alternate scan and scroll on long pages. The mention of specific target types adds further clarity.

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 explains when to use this tool versus scan_page: on long pages, one should scan, scroll, then scan again. It also provides clear guidance on how to specify the scroll target ('bottom', 'top', pixel offset, or CSS selector) and mentions the default timeout. This gives the agent precise usage instructions.

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