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

Annotations already disclose the key behavioral traits: destructiveHint=true, idempotentHint=true, readOnlyHint=false. The description reinforces which artifacts are destroyed (data + cache) but adds no auth requirements, running-state constraints, or irreversibility note beyond what annotations declare.

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?

Two short sentences, zero filler, purpose front-loaded before the clarifying analogy. Nothing to trim.

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 two-param destructive tool with full annotation coverage and no output schema, the definition covers what it does and what it wipes, and idempotency/destructiveness come from annotations. Only minor gaps remain (device/app state prerequisites), which is why it falls just short of a 5 rather than failing completeness.

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 both parameters are self-documented (UDID serial, package name with example). The description only confirms the target app, adding no new parameter semantics, so this sits at the baseline rather than above it.

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?

Specific verb+resource: 'Clear all data and cache for an app on an Android device.' The Settings equivalence ('Clear Storage') anchors the meaning precisely. It is clearly distinguishable from siblings like device_terminate_app, device_uninstall_app, and device_clear_app_locale.

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 Settings analogy implies when to use it, but the description never states prerequisites (app should be installed/not running) nor routes the agent among close siblings such as device_terminate_app (stops process), device_uninstall_app (removes app), and device_clear_app_locale (narrower reset). Usage is inferable, not explicit.

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