codex-computer-use-linux

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Scroll the X11 desktop

scroll

Scroll vertically in small increments. Provide a positive step count to scroll up or negative to scroll down, enabling precise navigation in Linux desktop applications.

Instructions

Scroll vertically by a small number of steps. Positive scrolls up and negative scrolls down. On Wayland use press_key with PAGEUP or PAGEDOWN instead.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "steps": "<steps>"
    },
    "name": "scroll"
  }
}

Input Schema

Name	Required	Description	Default
`steps`	Yes

Output Schema

Name	Required	Description	Default
`ok`	No
`action`	Yes
`backend`	Yes
`message`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 31, 2026

TDQS

A4.7/5.0

Behavior4/5

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

The description adds the crucial sign convention ('Positive scrolls up and negative scrolls down') and clarifies it is for X11 by contrasting with Wayland. Annotations provide no safety hints (all false), so this context carries the burden, and it does so adequately, though it doesn't disclose the exact mechanics of the scroll event.

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

Conciseness5/5

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

Two sentences, front-loaded with the action, then sign convention, then the alternative. Every sentence earns its place with zero fluff.

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

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter scroll tool with an output schema present, the description covers all necessary aspects: purpose, parameter semantics, alternative usage, and platform note. No significant gaps remain.

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

Parameters4/5

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

The schema has no description for 'steps' (0% coverage), but the description explains the direction meaning of positive/negative values. It does not specify what a 'step' exactly corresponds to (e.g., lines or notches), but the bounded range implies discrete increments, so the meaning is sufficiently clarified.

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

Purpose5/5

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

The description states 'Scroll vertically by a small number of steps' with a specific verb and resource (X11 desktop), and it distinguishes from siblings by explicitly naming press_key as the Wayland alternative. This is a clear, non-tautological purpose.

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

Usage Guidelines5/5

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

It gives explicit when-to-use guidance: 'On Wayland use press_key with PAGEUP or PAGEDOWN instead.' This tells the agent exactly when to avoid this tool and what to use instead, leaving no ambiguity about platform applicability.

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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