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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does add a specific behavioral detail: the display-name lookup is case-insensitive substring match against installed apps, which goes beyond the schema. However, it does not disclose what happens if the app is not found, whether the call is blocking, or if it causes side effects like bringing the app to foreground. This is a gap for a tool that modifies device state, but the disclosed matching behavior gives some transparency.

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 two sentences, concise and front-loaded with the core action. It efficiently conveys the main purpose and the key behavioral nuance of display-name matching. No wasted words; every sentence adds value. It is appropriately sized for a simple 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?

Given that there are many sibling tools including device_launch_app_in_language, the description omits crucial context about when to choose this tool over that one. It also does not mention any return format or failure behavior, which might matter for an agent that needs to verify success. For a tool that modifies device state, this is an incomplete picture even though the parameter set is small.

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%, with both parameters documented. The description adds no new meaning beyond what the schema already provides—the schema already mentions 'Package name (com.x.y) OR display name (case-insensitive substring)' for packageName. The description repeats this in prose without adding extra detail like format constraints or examples beyond the one given. Since the schema is complete, the baseline of 3 is appropriate.

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 it launches an Android app, with a specific verb and resource. It also explains the two input modes (package name or display name), which is helpful. However, it does not explicitly differentiate from siblings like device_launch_app_in_language, which is a similar launch tool with an additional parameter. Since the description names the platform (Android), it distinguishes from iOS counterparts, but the ambiguity with the language variant remains.

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 provides no guidance on when to use this tool versus alternatives. It explains how the tool works (accepting package or display name) but does not give context such as 'use this for simple launches' or mention that device_launch_app_in_language is for localized launches. There are no exclusions or comparisons, leaving the agent to infer when this tool is appropriate.

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