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

Annotations already signal destructive behavior, read-only=false, and non-idempotency. The description adds meaningful behavioral context beyond annotations: element ids are resolved at execution time, and on GNOME Wayland real drag requires the consent-backed Remote Desktop portal because XTEST/xdotool delivery is unreliable. This gives agents important operational expectations without contradicting any annotation.

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 three sentences with no filler. It front-loads the primary use case, then tucks the two important operational caveats (id preference and Wayland portal requirement) into compact, actionable prose. 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?

Given the tool's complexity — 11 parameters, two mutually exclusive source/destination groups, one required device parameter, backend enums, and an output schema — the description covers the key decision points an agent needs: when to use ids versus coordinates and which backend is required on Wayland. The per-parameter schema and output schema cover the remaining details. A small gap is that the description does not mention the destructive or irreversible nature indicated by annotations, but that is already surfaced structurally.

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 the schema already individually documents all 11 parameters. The description adds value by clarifying the semantic trade-off between from_id/to_id versus from_x/from_y/to_x/to_y and explaining why ids are preferred (current bounds resolved at execution time). This is meaningful context beyond the schema's per-parameter phrasing.

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 and resource: performing a 'real drag gesture between two UI element ids or coordinates.' It clearly distinguishes itself from generic input tools by specifying the gesture type and the source/destination semantics, and its scope is unambiguous even without opening the schema.

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 gives clear context for when to use the tool ('when the task calls for a real drag gesture') and provides concrete guidance on preferring element ids from ui_find/ui_snapshot over coordinates, including the rationale that bounds are resolved at execution time. It also gives platform-specific backend guidance for GNOME Wayland. It does not explicitly name sibling alternatives or state when not to use this tool, so it stops short of a full when/when-not contrast.

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