Launch App

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

Annotations mark destructiveHint as true, but the description adds no behavioral detail beyond 'launch' or 'open.' It does not explain what happens to the current app, whether the app is brought to the foreground, or why the operation is considered destructive. It provides no context beyond the annotation.

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 three short sentences, front-loading the main purpose without unnecessary fluff. The package-finding hint is concise, even though the referenced tool name is incorrect.

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?

Although the schema is detailed, the description references a nonexistent tool for discovering the required packageName and provides no clarification around the destructive annotation. This leaves the agent without reliable guidance for successful invocation.

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?

The input schema already covers all parameters with descriptions, so the baseline is 3. The only additional hint in the description is to find packageName via 'list_apps_on_device,' which is an inaccurate tool reference; it adds nothing about device or locale parameters.

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 clearly states the tool 'Launch an app on mobile device' and 'Use this to open a specific app,' giving a specific verb and resource. This distinguishes it from siblings like mobile_terminate_app, mobile_install_app, and mobile_open_url.

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?

It provides clear context for when to use the tool ('Use this to open a specific app'). However, it instructs calling 'list_apps_on_device' to find package names, but that tool is not in the sibling list—mobile_list_apps is the actual tool. This makes the guidance partly misleading and there are no exclusions or alternatives mentioned.

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