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

With no annotations provided, the description carries the full burden. It discloses the key behavior: 'Releases everything first, so nothing is left held down,' which tells the agent about internal cleanup. It also notes safety when no controller is attached, implying no error in that case. It does not mention return values or failure modes, but for a simple disconnect action, this is adequate.

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 three sentences, each serving a purpose: defining the action, explaining the internal behavior, and noting safety. There is no fluff, and the most important information (the action) is front-loaded.

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 one parameter, no output schema, and a straightforward action, the description covers the essential aspects: what it does, how it behaves, and when it's safe to call. No critical information is missing for an agent to invoke it correctly.

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 schema has 100% coverage for the single parameter 'udid' with a clear description ('Device serial number (UDID)'). The tool description adds no additional meaning or constraints beyond the schema, so the baseline of 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 clearly states the action ('Detach the virtual game controller'), the resource ('Android device'), and the metaphor ('as if unplugging it'), making it unambiguous. It distinguishes from sibling tools like device_gamepad_state and device_gamepad_status which are query operations, while this is an action.

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 gives a clear usage condition: 'Safe to call when no controller is attached' implies idempotency and safety, which is useful. However, it does not explicitly mention when to use this tool over alternatives like device_gamepad_disconnect (iOS counterpart) or other gamepad tools, but the action is distinct enough that the purpose itself serves as guidance.

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