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

Annotations already flag destructiveHint=true and non-idempotent, but the description adds real value beyond them: keycode 187 (APP_SWITCH) dispatch, a policy-gated shell, a UI settle wait, and the swipe-away sequence. It also sketches the return shape, which no output schema provides. It does not say what happens if the target card is absent, a minor gap.

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?

Four sentences, front-loaded with the core action before the mechanism and return value. The trailing "Returns { success, action, ... }" is slightly truncated but earns its place given there is no output schema.

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 mutation tool with no output schema, the description covers the action, the gating constraint, the internal sequence, and a return hint. It is nearly complete; only the not-found/no-target behavior and any permission prerequisites are unstated.

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%, so udid, all, and packageName are already documented in the schema. The description only echoes the "Close all" behavior of `all` and adds no syntax or format detail, so 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?

The description gives a specific verb+resource ("Open the Recents screen and dismiss an app card") and even names the mechanism, so an agent can tell what it does. It stops short of explicitly distinguishing itself from close siblings like device_terminate_app or device_clear_app_data, which also clear apps.

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?

"Useful for clearing background apps or verifying an app was killed" implies intent but never states when to pick this over device_terminate_app or device_clear_app_data. There are no exclusions or explicit alternative routing, leaving selection to inference.

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