scroll

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

With no annotations supplied, the description carries the full disclosure burden and does add real behavior: the scroll is page-sized with deliberate overlap, and fling introduces coasting that can skip items. It does not disclose what happens if no scrollable element exists, nor how timing/waiting parameters affect blocking or observation, leaving notable gaps.

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?

Two tightly packed sentences with the action and its scoping stated first and the fling trade-off immediately after; every clause carries information. Minor noise from quoting the direction names adds little, but the text is otherwise economical.

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?

An output schema exists, so return values need no explanation. For a seven-parameter gesture tool with zero annotation coverage, the description covers the core action semantics and the main behavioral trade-off, which is enough for an agent to call it correctly; the undocumented timing params are defaults that rarely need changing. This is adequate rather than exhaustive, but nothing critical to a correct call is missing.

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 compensate, and it partially does: direction, distance (fraction of height/width), fling, and the handle-vs-screen notion of target are all given meaning. Three parameters — duration_ms, max_wait_ms, and observe_after — get no explanation at all, so roughly half the surface remains undocumented.

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 names a specific verb (scroll) with its four directions and scopes it to either a scrollable handle or the whole screen, so the resource and action are unambiguous. It does not explicitly differentiate itself from the sibling gesture tools such as swipe, which keeps it from a 5.

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?

There is clear conditional guidance for one parameter: fling=True is recommended for long lists but warns that items can be skipped, which is useful trade-off guidance. However, there is no statement about when to use scroll versus swipe, or when a scroll is inappropriate (e.g., nothing scrollable on screen).

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