element_scrollScroll an element within a webpage to a specified position or bring it into view, using options for pixel distance and direction.
滚动元素（或让元素滚动到可视区域）。
| Name | Required | Description | Default |
|---|---|---|---|
| pixel | No | down/up 时滚动的像素 | |
| action | No | to_see=滚动到元素可见, to_top=滚到顶, to_bottom=滚到底, down=向下滚, up=向上滚 | to_see |
| element_id | Yes | find_element 返回的元素 id |
| Name | Required | Description | Default |
|---|---|---|---|
| ok | Yes | ||
| message | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description does not disclose side effects or behavior beyond the basic action. With only readOnlyHint=false in annotations, the description carries full responsibility, but it fails to mention whether scrolling waits for the scroll to complete, whether it affects other browser state, or if it throws errors on invalid actions.
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, concise sentence in Chinese with no redundant information. It is well-structured and easy to parse, though it could be slightly more informative about behavior.
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 simple scroll action, the description is adequate but not fully complete. It lacks context on when to use it, what the output is (though an output schema exists), and any edge cases or side effects. This leaves some ambiguity for an agent.
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?
The schema already includes descriptions for all parameters: element_id, pixel, and action with enum-like values. The tool description adds no additional meaning beyond what the schema provides, so it meets the baseline for complete schema coverage.
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 clearly states the tool scrolls an element or scrolls it into view, which distinguishes it from other scroll-related tools like vtable_scroll_viewport. However, it does not explicitly mention the action parameter's options in the tool description, though the schema covers them.
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 such as vtable_scroll_viewport or vtable_scroll_to_cell. It does not explain scenarios where pixel scrolling vs scroll-into-view is preferred, leaving the agent to infer usage.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.