scroll

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

With no annotations, the description carries the full behavioral burden. It discloses that the scroll is OS-level, momentum-based, occurs at the cursor position, and defines the sign convention for dy. It does not cover edge behaviors like whether the scroll is smooth or if it blocks, but for a simple scroll action the key behaviors are well explained.

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?

The description is two sentences, front-loaded with the core purpose, and every clause earns its place: OS-level, cursor position, sign convention, and the alternative tool. No fluff or repetition.

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?

Given no annotations and no output schema, the description provides sufficient context for a simple scroll tool: what it does, where it operates, the sign convention, and an alternative for a specific use case. It doesn't mention return values or failure modes, but those are unlikely to be critical for a scroll utility, so the description is nearly complete.

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 input schema already covers 100% of parameters with clear descriptions (dx, dy, ms), and the description adds the sign convention for dy ('dy > 0 scrolls the page DOWN'), though this is largely redundant with the schema's 'positive = down'. The description doesn't add meaningful parameter semantics beyond the schema, so baseline 3 is appropriate.

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 clearly states the tool performs an OS-level momentum scroll at the cursor position, with a specific verb ('scroll'), a clear resource ('OS-level'), and a location ('cursor position'). It also distinguishes itself from the sibling chrome_scroll by contrasting OS-level vs web-page-on-camera use.

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 explicitly says 'For scrolling a web page on camera, prefer chrome_scroll', providing a concrete alternative for a common scenario. It implies this tool is for OS-level scroll outside of that camera-specific web page context, giving clear when-to-use guidance.

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