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

With no annotations provided, the description carries the full burden. It discloses useful behavioral details: the hold-then-move sequence, coordinate units ('screen points'), and a prerequisite ('Requires an active iOS automation session'). Yet it does not mention return behavior, whether it waits for the gesture to complete, or potential side effects/edge cases, leaving some behavioral ambiguity.

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 sentences with no wasted words. The core gesture is front-loaded, followed by sibling differentiation, use cases, coordinate clarification, and the session requirement. Every sentence contributes distinct 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 a gesture tool with a 100%-covered parameter schema and no output schema, the description covers the essential context: what it does, how it works, typical use cases, coordinate semantics, and a prerequisite. It is slightly incomplete in not stating what the tool returns or whether it blocks until the gesture completes, but nothing critical is missing for invoking it correctly.

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 100%, so the baseline is 3. The description adds value by connecting the parameters into a temporal sequence: hold at (x1,y1) for holdMs to grab, then move to (x2,y2) over durationMs. This clarifies the relationship between start/end coordinates and the timing parameters beyond their individual schema descriptions.

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 opens with a specific action: 'Drag-and-drop on an iOS device' and then precisely explains the gesture sequence ('hold at (x1,y1) for holdMs to grab, then move to (x2,y2) over durationMs'). It also explicitly differentiates from ios_swipe by noting the absence of an explicit hold, which distinguishes it from a key sibling.

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 provides clear use cases ('home-screen icon reorder, drag-into-folder, slide-to-confirm') and contrasts with ios_swipe ('Distinct from ios_swipe (no explicit hold)'), giving the agent context for when this tool fits. However, it stops short of explicitly stating when not to use this tool or naming other alternatives like ios_drag_hid, so it lacks full exclusionary guidance.

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