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

Annotations already declare destructiveHint=true, readOnlyHint=false, idempotentHint=false and openWorldHint=true. The description reinforces this with concrete consequence language ('dropping can move files or change application state') and adds a verify-endpoints-first prerequisite that annotations cannot express — genuine added context, though it says nothing about failure modes, permissions, or what happens on an aborted drag.

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?

Two tight sentences, zero filler, with the action framing front-loaded before the risk note. Every sentence earns its place.

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 and annotations cover the safety profile, lowering the bar. However, for a 26-parameter destructive gesture tool with two distinct targeting modes, the description omits how to specify source and destination consistently, leaving an agent to infer valid parameter combinations that the schema does not enforce via required fields beyond 'device'.

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 coverage is 100% across 26 parameters, so the schema carries the burden and a baseline 3 applies. The description adds the useful framing that endpoints may be semantic elements or raw screen coordinates, but never names the corresponding parameter pairs (from_id/to_id vs from_x/to_x/from_y/to_y), hold_ms/duration_ms gesture timing, or the target mode selector.

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 verb (drag-and-drop / selection gesture) and scope (between native desktop elements or screen coordinates), which is much clearer than the bare tool name. It does not distinguish itself from close siblings such as drag_drop, pointer_down/pointer_move/pointer_up, or computer_select, so an agent cannot rule those out from the text 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?

"Confirm the source and destination first" implies a precondition, and the warning about consequences hints at when caution is needed. But there is no explicit guidance on when to pick this over drag_drop or a manual pointer_down/move/up sequence, and no statement of what 'verified' means or how to verify.

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