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Scroll

scroll

Move screen content in a chosen direction by a screen fraction, with optional verification that the screen actually moved.

Instructions

Scroll the content in direction (up | down | left | right) by distance (fraction of the screen). verify=true reports whether the screen actually moved (mobilerun-core).

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
msNo
deviceNo
verifyNo
distanceNo
directionYes

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

C2.9/5.0
Behavior3/5

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

With no annotations, the description carries the full behavioral burden. It usefully discloses that verify=true reports whether the screen actually moved, which is not in the schema, but it omits other relevant behavior such as whether the action is destructive, what permissions or app context are needed, and what happens on unsupported screens.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The definition is a single compact sentence plus a parenthetical note, with the core action and important parameters front-loaded. The '(mobilerun-core)' tag is minor noise but the description is otherwise efficient.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

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 not be explained, but the tool still has five parameters with zero schema descriptions and no annotations. The description leaves ms, device, and the choice among sibling scroll tools unexplained, which is inadequate for a tool with this much structured surface area.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

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, but it only explains direction, distance, and verify. The ms and device parameters remain completely undocumented in both the schema and the description, leaving an agent without semantics for two parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Scroll the content'), and enumerates the parameterized directions and distance unit. It does not explicitly name or contrast with the dedicated siblings scroll_up, scroll_down, scroll_left, scroll_right, scroll_to, or scroll_until, so the agent must infer when the generic form is preferred.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explains what the tool does but gives no when-to-use guidance, prerequisites, or comparison to alternative scrolling tools. It never says when to prefer this general tool over the specialized scroll_down/scroll_up/scroll_left/scroll_right or scroll_to.

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