android-emulator

Overview Schema Source Related Servers Discussions Admin

wait_for_element

Read-only

Polls Android UI until a queried element appears or disappears, with configurable timeout. Use after navigation or network calls to confirm screen state.

Instructions

Poll until an element matching the query appears (or disappears). Useful after navigation or network calls.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "query": "<query>"
    },
    "name": "wait_for_element"
  }
}

Input Schema

Name	Required	Description
`gone`	No	Wait for the element to disappear instead
`query`	Yes
`serial`	No	Device serial (e.g. emulator-5554). Optional when exactly one device is connected.
`timeout_seconds`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Sep 7, 2026

TDQS

A4.2/5.0

Behavior4/5

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

Annotations include readOnlyHint=true, so the read-only nature is already disclosed. The description adds valuable behavioral context: the polling mechanism and the ability to wait for either appearance or disappearance. It does not contradict annotations and adds meaningful information about the operation's dynamics.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two concise sentences with no redundant words. The core functionality is front-loaded, and the usage context is provided in the second sentence. Every part earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple polling tool with readOnlyHint annotation, the description adequately covers what it does, when to use it, and the key behavior (appear/disappear). It does not explain timeout error behavior, but the timeout_seconds parameter with default value provides that information. No output schema means return value is not critical.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 50% (gone and serial have descriptions; query and timeout_seconds do not). The description adds 'element matching the query', giving semantic meaning to the query parameter but not specifying its syntax. It does not address timeout_seconds, but the name is self-explanatory. This partially compensates for the schema gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb 'poll' and clearly states the resource: 'an element matching the query'. It distinguishes between appearing and disappearing, making it unambiguous. It is distinct from find_element (which likely returns a snapshot) and other interaction tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives a clear context: 'Useful after navigation or network calls.' This implies when to use it. However, it does not explicitly mention alternatives or when not to use it, such as using find_element for a single check.

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