Control an iOS simulator's Home, Volume Up, and Volume Down hardware buttons to automate device actions and testing.
Press a hardware button (home, volumeUp, volumeDown).
| Name | Required | Description | Default |
|---|---|---|---|
| button | Yes | Button to press | |
| device_id | Yes | Simulator UDID |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden, yet it only restates the operation. It does not disclose side effects (e.g. home backgrounding the app), press duration, or whether the target simulator must already be booted, all of which matter for a device-control mutation.
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 short sentence with the action front-loaded and the valid options inline; efficient, though extremely terse and lacking any qualifying context.
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?
An output schema exists so return values need not be explained, and the buttons are covered. However, for a device-mutating tool with no annotations, prerequisites (booted simulator, session) and the home-vs-go_home choice are unaddressed, leaving it only minimally complete.
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 100% with both parameters documented and the button enum self-explanatory, so the schema does the heavy lifting. The description merely repeats the enum values and adds no format or semantic detail beyond it, so the baseline 3 applies.
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 (press) and resource (hardware button) and enumerates the three supported buttons, so the agent knows exactly what the tool does. It does not, however, distinguish itself from siblings like go_home (which may also press home) or long_press, leaving ambiguity about which action to pick for the home button.
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?
There is no explicit guidance on when to use this tool versus alternatives: it never clarifies press_button 'home' vs go_home, or the distinction from long_press. Usage can only be inferred from the button enumeration.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.