long_press

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

Annotations provide readOnlyHint=false, destructiveHint=false, openWorldHint=true. The description adds nothing about behavioral traits beyond what annotations state - it doesn't mention what physical effect occurs (e.g., potentially triggering long-press actions, haptic feedback, or context menus). While no contradiction exists, the description contributes minimal behavioral context beyond the structured hints. There's also no mention of the device 'serial' parameter requirement or what happens without it.

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 a single, efficient sentence with zero waste. It's appropriately sized for a simple action tool. The only minor weakness is that it could mention the duration parameter implications, but for a tool of this simplicity, the brevity is well-earned.

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?

An output schema exists, so return values are presumably documented. However, for a physical action tool with openWorldHint=true and no safety annotations for a non-readOnly action, the description doesn't explain prerequisites (e.g., screen must be on, device must be connected) or the coordinate system (screen vs view-relative). Given the tool's simplicity and the output schema presence, this is somewhat adequate but leaves gaps around preconditions.

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 all 4 parameters (x, y, serial, duration) have descriptions in the schema. The duration parameter has a clear default (500ms) and semantics in the schema. The description itself adds no additional meaning beyond what the schema provides. Per guidance, with high coverage, baseline 3 is appropriate since the description doesn't compensate with extra context like coordinate format or coordinate-space reference.

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 'Perform a long press at the specified coordinates' uses a specific verb (perform long press) with a clear resource (specified coordinates). It clearly differentiates from siblings like 'tap' (single tap) and 'swipe'/'drag_drop' (motion actions). However, it doesn't explicitly name the distinguishing sibling alternative, and the purpose is clear but could be more explicit about what a long press is for (e.g., context menus).

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?

No guidance is provided on when to use this tool versus alternatives like 'tap' or 'ui_tap_element'. The description gives no context about use cases (e.g., long-press to reveal context menus) or exclusion criteria (e.g., when a simple tap suffices). This is a pure action tool with zero usage context provided.

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