mobile_long_press

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals the action and return type, but does not mention the hold duration, coordinate origin, behavior on invalid coordinates, or any side effects such as triggering a context menu. This is minimal behavioral information for a no-annotation tool.

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 description is compact and well-structured: action first, then a parameter list, then return type. There is no filler or redundant explanation, making it easy for an agent to parse quickly. The optional 'Returns' line is short and consistent with the API-oriented framing.

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?

This is a simple three-parameter tool with an output schema already present, so the description does not need to explain return values in depth. It supplies the essential invocation details: which device, where to press, and in what units. Minor missing context such as coordinate origin and hold duration prevents a perfect score.

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%, so the description must compensate, and it does for all three parameters. serialno is tied to list_devices, and x/y are explicitly specified as device pixels. This adds meaningful context the schema's bare titles do not provide, though it could clarify the coordinate origin.

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 states a specific action, 'Press and hold', applied to a clear resource, 'screen coordinates' on a mobile device. This inherently distinguishes it from siblings like mobile_tap, mobile_double_tap, and mobile_swipe, so an agent can identify what the tool does without needing the name alone.

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 guidance about when to use this tool instead of mobile_tap, mobile_double_tap, or mobile_swipe. The description explains what the tool does but not the conditions or scenarios that warrant a long press, leaving the selection decision unsupported.

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