start_app

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states that it launches an app, but does not mention side effects like bringing the app to the foreground, potentially leaving the current screen, or the meaning of the 'stop_first' parameter. This is very limited behavioral transparency for a state-changing operation.

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 no filler words. It efficiently conveys the core action and the key parameter context in a compact form.

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 the tool is relatively simple and has an output schema, the description omits important context such as the effect of 'stop_first', the meaning of 'activity', and any prerequisites like device connectivity. For a state-changing tool with no annotations, this is insufficient for an agent to invoke it correctly in all situations.

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 0%, so the description must compensate. It only explains 'package_name' implicitly via 'by package name'. The 'activity' and 'stop_first' parameters, both with defaults, are not described at all, leaving their purpose and usage unclear.

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'), a clear resource ('an app on the current device'), and the key identifier ('by package name'). This distinguishes it from siblings like 'stop_app' and 'clear_app_data' without needing to inspect the schema.

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: when you need to launch an app on the current device. However, it does not provide explicit guidance on prerequisites such as a connected device, nor does it mention alternatives or when not to use this tool. The context is clear but lacks exclusionary or prerequisite information.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.