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

Annotations already declare destructiveHint=true, openWorldHint=true, and non-idempotent, so the safety profile is covered. The description adds real value beyond that by stating the post-action observation ("Answers the page after it: the elements and text in view, with the same numbers"), which tells the agent it gets a fresh numbered snapshot for follow-up steps. It says nothing about the dialog/dialog_text behavior or irreversibility of drag outcomes, keeping it from a 5.

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 short sentences, zero filler. The action and its endpoints come first, the return behavior second, and the illustrative examples are embedded rather than listed separately.

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?

For a five-parameter tool with nested from/to objects and no output schema, the description covers the action, the endpoint duality, and the return snapshot, which is what an agent needs to chain steps. The omission of dialog handling is a minor gap since the schema documents those fields fully.

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%, and each nested coordinate/element field, the app slug, and the dialog enum are documented in-schema. The description adds no semantics beyond the schema, so the baseline 3 applies.

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 gives a specific verb and mechanics: "Drags from one element or point to another," and concretizes it with three recognizable scenarios (card between columns, piece on a board, slider handle). It is unmistakably distinct from cotlet_browser_click or cotlet_browser_hover by name and by the two-endpoint structure, though it does not explicitly name those siblings.

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 example scenarios implicitly tell an agent when this tool is the right choice: drag-and-drop reordering, board moves, slider manipulation. There is no explicit "do not use this for X, use click instead" exclusion or precondition guidance, so it falls short of the 5 bar.

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