Verify that a UI element is absent from view on a mobile app within a specified timeout, enabling automated tests to confirm element disappearance or non-visibility.
Assert that a locator is not visible within timeout.
| Name | Required | Description | Default |
|---|---|---|---|
| locator | Yes | ||
| serverUrl | No | ||
| sessionId | Yes | ||
| timeoutMs | No |
Changes observed during successful MCP inspections.
v0.1.0-alpha.14Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It mentions 'within timeout' but does not explain whether the tool polls, fails immediately, requires the element to exist, or what happens on timeout. This is minimal for a tool meant to gate test validity.
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?
A single front-loaded sentence with no filler words. It is concise, though it sacrifices necessary behavioral detail for brevity.
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 four parameters, a nested locator object, no output schema, and no annotations, this description is too thin. An agent cannot infer the full calling contract, failure semantics, or default timeout behavior from it.
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 0%, and the description only loosely references 'locator' and 'timeout.' It does not explain sessionId, serverUrl, the nested locator structure, whether timeoutMs is optional, or how the strategy/value pair is interpreted.
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 ('assert'), resource ('a locator'), and negation ('not visible') with a timeout scope. The 'not visible' phrasing clearly differentiates it from siblings such as appium.assert_visible and appium.wait_for_visible.
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 is given on when to use this versus assert_visible or wait_for_visible. The description conveys only what the tool does, not the conditions that should lead an agent to choose it over alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.