Scrolls the main content of an Android app view down, up, left, or right, letting AI agents move through Gmail, Calendar, or Drive screens by a set number of swipes.
Scroll the main content ('down' shows what is below, 'up' goes back toward the top).
| Name | Required | Description | Default |
|---|---|---|---|
| times | No | Number of swipes. | |
| amount | No | Fraction of the scroll area per swipe (0.1-0.9). | |
| direction | No | down, up, left or right. | down |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It does add genuinely useful semantics by defining what 'down' and 'up' mean relative to the page, but it says nothing about whether the action blocks or settles before returning, what happens when a scroll limit is reached, or whether any feedback is returned.
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?
A single front-loaded sentence with the verb and resource first and the clarifying parenthetical after. No filler text, and the direction semantics come before any agent would need to consult the enum.
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 tool is simple, all three parameters are optional with defaults fully documented in the schema, and no output schema exists to explain. The description is nearly sufficient; only post-scroll observability (e.g. taking a screenshot to confirm movement) is left implicit.
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 coverage is 100%, so baseline would be 3, but the description adds meaning the schema lacks by explaining the direction enum in terms of viewport behavior ('down' shows what is below, 'up' goes back toward the top). It leaves 'left'/'right' and the times/amount parameters to 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?
States a specific verb (scroll) and the target resource (the main content), and clarifies what the two primary directions mean. It does not explicitly name the nearest sibling (ui_swipe) or explain how this differs from a raw gesture, so differentiation is only implied.
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?
Usage is implied by 'main content' — this is the scroll to use for the page body rather than a pane — but there is no explicit when-to-use versus ui_swipe, ui_dump, or gmail_scroll, and no guidance on needing a screenshot afterward to observe the result.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.