Start an iOS app on a specific simulator using its bundle ID, enabling automated UI testing and direct interaction through WebDriverAgent.
Launch an application by bundle ID.
| Name | Required | Description | Default |
|---|---|---|---|
| bundle_id | Yes | App bundle ID (e.g., com.apple.Preferences) | |
| 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 burden. It does not disclose whether the app must be installed, whether launching fails if already running, whether it waits for launch completion, or any side effects or return behavior. For a mutation/action tool with zero annotation coverage, this is a significant gap.
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?
The description is a single, front-loaded sentence with zero waste. It is appropriately sized for a simple two-parameter action tool.
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?
While an output schema exists, the description lacks essential context for an action tool with no annotations: prerequisites (device must be booted), failure modes (app not installed), and interaction with similar tools like open_url. The description is too sparse to fully inform correct invocation in a simulator environment.
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 both parameters are fully documented in the schema, including an example bundle ID. The description adds no parameter details beyond what the schema provides, which is acceptable but not value-adding. Baseline 3 is appropriate when schema does the heavy lifting.
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?
The description states a specific verb (Launch) and resource (application), making the tool's primary action clear. It is distinguishable from terminate_app, list_apps, and other siblings by its focus on starting an app by bundle ID. However, it does not explicitly differentiate from open_url, which could also start apps via URL schemes.
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?
The description implies usage: use this to launch an app when you have its bundle ID. It does not state when NOT to use it, prerequisites (e.g., simulator must be booted), or alternatives like open_url or list_apps. This is the minimum viable guidance for an agent to infer the tool's purpose.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.