mobilerun-mcp

Scroll Left

scroll_left

Scrolls the screen left to reveal content that is off-screen to the left, such as hidden menus or items.

Instructions

Scroll the content left (reveal what is to the left).

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "scroll_left"
  }
}

Input Schema

Name	Required	Description	Default
`amount`	No
`device`	No
`som_id`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 27, 2026

TDQS

C2.6/5.0

Behavior2/5

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

With no annotations provided, the description must carry the full burden of behavioral disclosure. It mentions the effect ('reveal what is to the left') but does not explain how the 'amount' parameter influences scrolling, what device or som_id are for, or any side effects or limitations. This is minimal behavioral transparency.

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 description is a single, clear sentence with no filler. It is appropriately concise and front-loads the action. However, its brevity borders on under-specification, which is more a completeness issue than a conciseness issue. The structure is effective.

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?

For a tool with three parameters, no annotations, and no parameter explanations, the description is incomplete. It does not cover parameter semantics, usage context, or behavioral details beyond the basic action. The presence of an output schema mitigates the need to explain return values, but the lack of parameter guidance is a significant gap.

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

Parameters1/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has 0% description coverage, and the description provides no information about the three parameters (amount, device, som_id). The description does not compensate for the lack of schema documentation, leaving the agent without any understanding of what these parameters mean or how to set them correctly.

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?

The description clearly states a specific verb ('scroll') and resource ('content') with a direction ('left'), and adds 'reveal what is to the left' to clarify the effect. It is distinguishable from other scroll tools like scroll_right and scroll_up, though it does not explicitly name them. This is clear and purposeful, not a tautology.

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?

There is no guidance on when to use this tool versus alternatives like scroll_to, scroll_right, or swipe. No context is provided for choosing this over a generic swipe or scroll. The description only states the action without any situational direction.

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

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