app_stopForce-stops an Android app on a connected device, with an option to wipe its data for a clean restart or test reset.
Force-stop an app, optionally also clearing all of its data.
| Name | Required | Description | Default |
|---|---|---|---|
| serial | No | Device serial from devices_list. Optional when exactly one device is online. | |
| package | Yes | Application package / applicationId | |
| clearData | No | pm clear: wipes the app's data |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, so the safety bar is lower. The description adds that data clearing is optional and wipes all app data, which is useful framing, but it does not state that force-stop itself kills the running process (and any unsaved state) or that the data wipe is irreversible and leaves the app installed.
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 clause naming the action and its optional destructive variant, with zero filler. Nothing is repeated and the destructive option is signalled early enough to shape the call.
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 simple 3-parameter tool with full schema coverage, an annotation for destructiveness, and no output schema, the description is close to sufficient. The remaining gap is not clarifying that clearData wipes data while keeping the package installed, which is the one point that could be mistaken for app_uninstall.
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%, so all three parameters — including the 'pm clear' semantics of clearData and the serial default — are already documented in structured data. The description only restates the optional clearData concept, adding no syntax or device-targeting detail beyond the schema.
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: 'Force-stop an app', with the optional data-wipe scope. It is clear what the tool does, but it never distinguishes the operation from nearby siblings such as app_uninstall (remove app) or app_launch (start it), leaving that contrast implicit.
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?
Usage is only implied by the verb — an agent infers you call this to terminate a running app. There is no statement of when to prefer this over app_uninstall or how clearData changes the decision, and no prerequisites named in the description (the serial/device-online condition lives only in the schema).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.