Scroll Android app content in a chosen direction to view off-screen elements. Specify package and container, or let it auto-detect the scrollable area.
滚动（down=查看下方内容，手指上滑）
| Name | Required | Description | Default |
|---|---|---|---|
| pkg | No | ||
| container | No | scrollable 容器选择器，缺省自动找 | |
| direction | No |
Changes observed during successful MCP inspections.
v0.5.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It says nothing about what happens on scroll, whether the pkg argument changes behavior, what occurs at the edge of scrollable content, or what the tool returns. The only behavioral hint is the direction-to-gesture mapping.
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?
Extremely terse — a single clause. Front-loads the verb, which is good, but it is arguably under-specified rather than efficiently concise given three parameters.
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?
No output schema, no annotations, and only 33% schema description coverage. The description does not explain the pkg parameter, the container auto-find fallback behavior, or scroll edge behavior, leaving the agent with clear gaps for a 3-parameter UI tool.
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 only 33%, so compensation is expected. The parenthetical usefully explains that direction=down means viewing content below via an upward finger swipe, which is real added meaning beyond the bare enum. However, pkg remains entirely undocumented in both schema and description.
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?
Names a specific verb (scroll) and clarifies the direction semantics in a parenthetical. An agent can tell it apart from ui.click or input.swipe, though the description never explicitly contrasts with input.swipe, which could also produce 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?
There is no guidance on when to use ui.scroll versus scrolling sibling tools like input.swipe, nor any preconditions. The direction hint implies usage but does not state it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.