scroll

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

There are no annotations, so the description carries the behavioral transparency burden. It does add meaningful direction-to-effect mapping, such as 'up' meaning go back and left/right moving between pages. However, it does not mention scroll amount, behavior at scroll boundaries, or how the optional device parameter affects the action.

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 sentence delivers the core action and all direction semantics with no filler. The information is front-loaded and every part earns its place.

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 and has an output schema, so return values do not need elaboration. Still, the device parameter is entirely unexplained, and with zero schema descriptions and no annotations, an agent cannot confidently know whether it must supply a device or how that value is used.

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?

The schema provides no parameter descriptions, but the tool description explains the direction parameter's values and their effects. The device parameter, however, is completely undocumented, leaving ambiguity about whether and how to specify a target device.

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?

The description states a specific action ('Scroll the screen') and resource, and immediately clarifies what each direction does. It is neither a tautology nor vague, and it clearly distinguishes this tool from siblings like tap, type_text, and chrome_navigate.

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?

The description gives clear context: use 'down' to see content further down the page, 'up' to go back, and left/right to move between pages. It does not explicitly state when not to use this tool or name alternatives, but the usage context is strong enough for an agent to make a sensible selection.

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