Swipe

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

With no annotations, the description carries the full burden and does well: it discloses that js mode performs a container scroll with no touch, os mode is a real device gesture, and auto tries js first and reports the fallback reason. It does not cover permissions, return values, or what happens with missing parameters, but the core behavioral distinctions are unusually 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 two operating modes are front-loaded in the first sentence, and the delivery-path explanation follows efficiently. The second sentence is dense but every clause adds useful information.

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 an 8-parameter tool with zero required parameters, no annotations, and no output schema, the description leaves important gaps: it does not clarify that at least a direction or a full coordinate pair is needed, nor does it explain duration_ms or device. It is minimally viable for the core use cases but not 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?

Schema description coverage is 0% for 8 parameters, so the description must compensate. It meaningfully explains 'via' values and implies that direction and coordinate modes exist, but it does not clarify whether x1/y1/x2/y2 must be supplied together, what device selects, or what duration_ms controls.

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 (swipe) and two clear modes: by direction scaled to the screen, or between explicit coordinates. It is clear what the tool does, though it does not explicitly distinguish itself from the sibling scroll_to tool.

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?

Provides useful guidance on how to choose the 'via' delivery path (js vs os vs auto), including fallback behavior. However, it gives no guidance on when to use swipe instead of sibling tools like scroll_to or tap, and does not state when not to use it.

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