Lists text-bearing UI elements on the connected iPhone screen with type, label, center coordinates, and size, optionally filtered by label/name/value substring.
列出屏幕上带文字的界面元素:类型、标签、中心点坐标、尺寸。
filter: 只返回标签/名字/值里包含该文字的元素(不区分大小写)。 注意:按坐标判断是否在屏幕内,被弹窗遮住的元素也可能列出来,不确定时截图核对。
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| filter | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With zero annotations the description carries the full burden, and it discloses non-obvious traits: on-screen determination is coordinate-based, and elements obscured by popups may still be listed. It also notes case-insensitive matching. It does not cover ordering, truncation via limit, or performance cost.
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?
Three short lines: what is returned first, then the filter semantic, then the caveat. Every sentence adds information an agent would otherwise have to guess.
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?
No output schema and no annotations, so the description correctly spells out the return shape and the key reliability caveat. The only real gap is the undocumented `limit` behavior, a minor omission for a two-parameter read tool.
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%, so the description must compensate. It does so fully for `filter` (case-insensitive substring over label/name/value, which is more specific than the schema's bare 'string'), but `limit` (default 150) is never mentioned — what it caps and what happens on truncation is left unexplained.
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?
States a specific verb and resource (列出屏幕上带文字的界面元素) and enumerates the returned fields (类型、标签、中心点坐标、尺寸), which distinguishes it from iphone_screenshot (pixels) and iphone_tap_element (action on an element). An agent knows exactly what it gets back without opening a 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?
Implies the use case (inspecting text-bearing elements to locate one before tapping) and explicitly routes to iphone_screenshot when the listing is ambiguous (不确定时截图核对). No explicit 'when not to use' or guidance on when iphone_tap_element suffices on its own.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.