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, and it does so thoroughly. It reveals that the tool force-stops the app first (so the new locale takes effect on cold launch), that the override persists until cleared or uninstall, and that it requires Android 13+. This is exactly the kind of side-effect and condition information an agent needs.

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?

Three sentences, each earning its place: the purpose is front-loaded, then the platform requirement and underlying API, then the crucial behavioral side effects (force-stop and persistence). There is no fluff or repetition of schema information. Excellent economy.

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 tool with three straightforward parametersable and no output schema, the description covers everything an agent needs to decide to call it and predict its effects: what it does, the prerequisite (Android 13+), how it achieves it, the side effect (force-stop), and the lifecycle of the override. Nothing material is missing.

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 provides 100% description coverage, with examples for all three parameters (udid, locale, packageName). The description adds no additional parameter semantics beyond what the schema states, so the baseline of 3 is appropriate. No gap to compensate for.

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 resource ('an Android app'), and the distinguishing constraint ('forced into a specific language / locale without changing the device's system settings'). It also names the platform and API level, which separates it from generic device_launch_app and system-language tools. This is unambiguous and immediately actionable.

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 clearly implies when to use this tool: when you need per-app language override without altering system settings, on Android 13+. It also implies the alternative (changing system settings) by explicitly stating what it does not do. However, it does not expressly name sibling alternatives like device_set_device_language or device_clear_app_locale, leaving some routing inference to the agent.

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