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

Goes well beyond the annotations by disclosing the underlying mechanism (cmd locale set-app-locales / per-app LocaleManager), a hard platform prerequisite (Android 13+, API 33), and a real side effect: the tool force-stops the app first, so in-flight app state is destroyed. It also documents persistence semantics (override survives until cleared or uninstall), which matters given idempotentHint=false and no output schema.

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?

Purpose and the key constraint are front-loaded in the first sentence, followed by tightly packed requirement, mechanism, side-effect, and persistence details with no filler. Slightly dense at five sentences, but every sentence carries non-redundant information.

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 three-parameter launch tool with no output schema, the description supplies everything an agent needs: platform requirement, what gets interrupted (force-stop), how the override is implemented, and how long it lasts. Nothing material is left to inference.

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 coverage is 100% and the schema already defines udid, packageName, and locale with examples, so the description is not required to carry parameter meaning. It reinforces the locale concept ('specific language / locale') but adds no syntax or format detail beyond the BCP-47 example already in the schema. Baseline 3 applies.

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?

States a specific verb and resource (launch an Android app) plus the defining modifier (forced into a specific language/locale), and explicitly scopes it against the obvious alternative behavior: 'without changing the device's system settings'. That distinguishes it from device_launch_app and device_set_device_language without opening either 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?

Gives clear context for use (per-app locale forcing on Android 13+) and notes the override persists 'until cleared', which implicitly points at device_clear_app_locale. It never explicitly names device_launch_app or device_set_device_language as the alternatives to reject, so it falls short of a full when/when-not routing statement.

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