Drag from one point to another on a connected iPhone or iPad to simulate touch gestures for app development testing.
Drag from one point to another (points).
| Name | Required | Description | Default |
|---|---|---|---|
| toX | Yes | ||
| toY | Yes | ||
| fromX | Yes | ||
| fromY | Yes | ||
| device | No | Device UDID or name substring. Defaults to the select_device choice, then IOS_DEVICE_MCP_DEVICE, else the single USB-connected device. | |
| duration | No | Seconds (default 0.3) |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden, yet it discloses nothing about side effects (inertial scrolling, unintended app state changes), required device selection, or default gesture timing. The only behavioral hint ('points') is ambiguous about units and coordinate space (screen vs. app).
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 single sentence is efficient and front-loaded with the verb, but its brevity reflects under-specification rather than tight writing — nothing beyond the bare action is stated.
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 6-parameter gesture tool with no annotations and no output schema, the description omits coordinate semantics, duration/default timing, device targeting, and the return/observable result. It is not complete enough for an agent to invoke it confidently.
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 only 33% (duration and device are documented in-schema; the four coordinate params are not). The description's '(points)' is the sole clue for fromX/fromY/toX/toY and does not clarify units, coordinate origin, or screen-vs-device space, so it fails to compensate for the coverage gap.
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 verb+resource ('Drag from one point to another') identifies a swipe/drag gesture, which is meaningfully distinct from siblings like tap and long_press. However, it never states the tool's scope (gesture on the currently selected device/screen) or how it differs from scroll, leaving the purpose only loosely defined.
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?
There is no when-to-use or when-not-to-use guidance. The agent must infer on its own that swipe is for drag gestures and that scroll might be preferred for list navigation, with no explicit routing between these overlapping siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.