scroll

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

With no annotations, the description carries the full burden. It usefully discloses that coordinates are derived from the real screen size so it works on any resolution, but says nothing about the fact that this simulates an input gesture, whether it animates/waits for the scroll to settle, or what it returns.

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 usage hint, then the resolution note. No filler, though the middle sentence is narrower than a general usage statement.

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?

For a 3-parameter gesture tool with no annotations and no output schema, the description covers the mechanics but omits the scroll-vs-swipe relationship and any behavioral detail about gesture execution. Adequate but with clear gaps.

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 67% ('amount' and 'device' are documented in the schema; 'direction' only has an enum). The description reinforces the meaning of 'direction' with a concrete example and explains that the travel amount is resolution-independent, but adds nothing for 'device' beyond the 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?

States a specific verb and resource ('Scroll the dominant axis of the screen'), which is concrete and unambiguous. It does not, however, distinguish itself from the sibling tool 'swipe', which is the obvious adjacent gesture and could be confused with it.

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 offers a hint for one parameter value ('Use direction \'down\' to reveal content further down the page'), which implies intended usage, but gives no guidance on when to choose scroll over swipe, no prerequisites, and no exclusions.

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