browser_dragDrag one element onto another in a browser to move, reorder, or drop items. Specify source and target element references to complete the action.
Drag element ref_a onto element ref_b.
| Name | Required | Description | Default |
|---|---|---|---|
| tab | No | ||
| ref_a | Yes | ||
| ref_b | Yes | ||
| session | No | default |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description bears the full burden. It only states the action without disclosing any side effects, such as whether the drag triggers events, clicks, or navigation, or whether it waits for drag-and-drop to complete. No mention of potential delays or failures.
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?
Single sentence, concise and to the point. It is efficient but lacks necessary context. However, for a simple tool, the brevity is acceptable, and the structure is clear.
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?
The tool is simple in complexity, but with zero schema coverage and no annotations, the description is insufficient. It doesn't explain what ref_a and ref_b refer to, nor the behavior of the drag operation (e.g., does it need a page loaded? what happens on success?). An agent would have to guess.
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 0%, and the description only maps two parameters (ref_a, ref_b) to 'drag element ref_a onto ref_b'. Parameters 'tab' and 'session' are not explained at all, and ref_a/ref_b are not elaborated (e.g., they are references to what? DOM element ids?). The description fails to compensate for the schema's lack of descriptions.
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?
Description clearly states the action (drag) and the two required elements (ref_a onto ref_b). It is distinct from siblings like browser_click or browser_scroll, but doesn't explicitly differentiate from potential drag-and-drop alternatives (none exist). The verb and resource are specific enough.
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?
No guidance on when to use this tool vs alternatives, nor any conditions or prerequisites (e.g., requires elements to be visible, or that a page must be loaded). The description is minimal and doesn't mention when not to use it. This is a common gap.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.