Stops the on-device driver process for a selected iPhone or iPad, ending active device control sessions. Target a device by UDID or name substring.
Stop the on-device driver.
| Name | Required | Description | Default |
|---|---|---|---|
| device | No | Device UDID or name substring. Defaults to the select_device choice, then IOS_DEVICE_MCP_DEVICE, else the single USB-connected device. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It does not disclose that stopping the driver halts device control, whether in-flight sessions are affected, whether it is reversible via start_driver, or what errors occur if no driver is running.
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. It is efficient, though its brevity reflects under-specification rather than disciplined concision.
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 state-changing tool with no annotations and no output schema, an agent still needs to know that this disables subsequent device operations and how to restore functionality. None of that context is present.
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 100%, and the device parameter's fallback chain (select_device, env var, single USB device) is fully documented in the schema. The description adds nothing beyond it, which meets the baseline for fully-covered schemas.
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?
Clearly states the specific verb and resource: stopping the on-device driver. The counterpart sibling start_driver makes the scope inferable, but the description never explicitly differentiates itself from it or from terminate_app-style siblings.
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 indication of when to call this versus leaving the driver running, or what should precede/follow it (e.g., session teardown). The only implied guidance comes from the sibling name start_driver, not the description itself.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.