launch_appLaunch an installed app on the active device by iOS bundle ID or Android package name, with options to restart a running app and pass launch environment variables on iOS.
Launch an app by bundle id (iOS) / package name (Android) on the active device. Optional: terminate_running to restart a running app, env to pass launch environment variables (iOS only).
| Name | Required | Description | Default |
|---|---|---|---|
| env | No | ||
| app_id | Yes | ||
| device | No | ||
| terminate_running | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It usefully discloses that env is iOS-only and that terminate_running restarts a running app, but says nothing about error behavior (e.g. app not installed), whether the call waits for launch to complete, or whether it foregrounds an already-running app.
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?
Two tight sentences, front-loaded with the core action and identifier format, then the optional behaviors. Almost no waste; only the unexplained device parameter leaves something missing.
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 mutation tool with no annotations and no output schema, the description covers the main action and two optional parameters but omits the device parameter and any launch-failure or post-condition behavior. Adequate but with clear gaps.
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 0%, so the description must compensate. It explains terminate_running, env (including the iOS-only restriction absent from the schema), and the app_id format, but the device parameter is never mentioned despite the schema exposing it.
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 (launch) and resource (an app), and clarifies the identifier format per platform (bundle id on iOS / package name on Android). It does not explicitly distinguish itself from siblings like install_app or reload_app, but the action is unambiguous.
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 implied: launch an app on the active device. There is no explicit guidance on when to use this versus install_app, reload_app, or open_url, nor any stated prerequisite such as the app needing to be installed first.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.