Mobile Next MCP

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

Annotations provide destructiveHint=true, indicating potential side effects. The description adds context by specifying the action is a 'double-tap' gesture, which implies it might trigger UI interactions (e.g., opening apps, confirming actions). However, it doesn't detail specific risks (e.g., data loss) or rate limits beyond the annotation's safety warning.

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, front-loaded sentence that directly states the tool's function without unnecessary words. Every part ('Double-tap on the screen at given x,y coordinates') is essential and earns its place, making it highly efficient and well-structured.

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?

Given the tool's moderate complexity (destructive action with 3 parameters), no output schema, and rich annotations, the description is mostly complete. It clearly defines the action but lacks details on expected outcomes (e.g., what happens after double-tap) or error conditions. However, annotations cover safety, and schema covers parameters adequately.

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%, with clear descriptions for device, x, and y parameters. The description adds no additional semantic meaning beyond the schema, such as coordinate system details (e.g., origin at top-left) or device selection tips. Baseline score of 3 is appropriate as the schema fully documents parameters.

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 clearly states the specific action ('double-tap') on a specific resource ('screen') at specific coordinates ('given x,y coordinates'). It distinguishes from siblings like mobile_click_on_screen_at_coordinates (single tap) and mobile_long_press_on_screen_at_coordinates (long press) by specifying the double-tap gesture.

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 implies usage for double-tapping at coordinates but doesn't explicitly state when to use this vs. alternatives like single tap or long press. It provides no guidance on prerequisites (e.g., device must be unlocked) or exclusions (e.g., not for scrolling). Usage is contextually implied but not explicitly defined.

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