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

With no annotations present, the description carries the full behavioral burden and does so thoroughly. It discloses that the controller stays connected by default, that re-registering costs ~5 seconds, that unplugging leaves a permanent and unremovable device entry, and that streamed controllers can re-send frames and mask a successful release.

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 front-loaded with the primary behavior and then proceeds through default behavior, the unplug variant, and long-term side effects in a logical order. Although longer than average, every sentence contributes a distinct operational implication rather than filler.

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-parameter tool with no output schema, the description is complete: it covers the common use case, an important edge case, the default behavioral contract, the parameter variant, and the irreversible side effect. An agent has enough context to invoke it correctly and anticipate consequences.

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 already documents both parameters with 100% coverage, so the baseline is 3. The description adds strong semantic value to 'unplug' by explaining the operational consequence, the recommendation context, and the future cost of re-registering, which is beyond what the schema alone offers.

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 opens with a specific action: 'Release every input the virtual game controller is holding on an iOS device,' naming the verb, resource, and platform clearly. It also covers the secondary streaming-controller behavior, so the full purpose is unambiguous and distinguishable from state/status siblings.

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?

It gives explicit situational guidance: 'Call this when finished,' plus a clear decision rule for default behavior versus unplug:true and a recommendation for handing the device back. It does not explicitly name sibling alternatives like device_gamepad_disconnect, so it stops just short of full alternative routing.

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