Android MCP

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

Annotations include destructiveHint: true, indicating this is a mutation operation. The description adds minimal behavioral context by implying movement ('drag from... drop on'), but doesn't elaborate on effects (e.g., what gets moved, if changes are reversible) or other traits like permissions or rate limits. With annotations covering the destructive nature, the description adds some value but is limited.

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, straightforward sentence that efficiently conveys the basic action. It's front-loaded and avoids unnecessary words, though it could be more informative without sacrificing brevity.

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 has 4 parameters with 0% schema coverage, no output schema, and annotations only indicate destructiveness, the description is inadequate. It doesn't explain what the tool returns, the context of use (e.g., device interaction), or fully clarify parameter roles, leaving significant gaps for agent understanding.

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 parameters x1, y1, x2, y2 are undocumented in the schema. The description implies these are coordinates for drag-and-drop but doesn't specify their meaning (e.g., screen pixels, relative positions), units, or constraints. It adds minimal semantics beyond the action, failing to compensate for the schema 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 description 'Drag from location and drop on another location' restates the tool name 'Drag' in a slightly expanded form, making it tautological. It doesn't specify what resource is being dragged (e.g., UI element, file) or the context (e.g., screen, interface), leaving the purpose vague beyond the basic action implied by the name.

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 no guidance on when to use this tool versus alternatives like Click, Swipe, or Press. It doesn't mention any prerequisites, exclusions, or specific scenarios where dragging is appropriate, leaving the agent with no contextual usage information.

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