Scroll

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

No annotations exist, so the description carries the full burden. It discloses a key failure mode ('scrolling a single row does nothing') and a fallback path, which is exactly the kind of non-obvious behavior an agent needs; it does not mention scroll magnitude, whether it stops at boundaries, or any device-side effects, so it stops short of full disclosure.

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?

Three short sentences, front-loaded with the action, then the critical constraint, then the alternative. No wasted clauses, though the ref constraint and the alternative could arguably be merged to tighten it further.

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?

An output schema exists, so return values need no explanation. For a 3-param no-annotation tool the description covers the make-or-break detail (which ref to pass) and the escape hatch, but leaves `device` and scroll distance unspecified.

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?

Schema coverage is 0%, so the description must compensate. It does well for `ref` (must be the container's ref, not a row's) and implies the `direction` value set (up/down/left/right), but says nothing about `device` or how direction strings are formatted. Partial compensation for a three-parameter, undocumented schema.

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 first sentence gives a specific verb (scroll) plus the resource (list/container) and the supported directions, which maps directly to the `direction` param. It also implicitly separates itself from `swipe`, the closest sibling, by naming it as the fallback for a different case.

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?

States an explicit precondition (the ref must be the scrollable container, not a row) and an explicit alternative with the condition that selects it: if the container has no ref, use swipe(). Nothing about when to use this vs. swipe is left to inference.

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