press_key

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states that a key is pressed but does not disclose how the device parameter is resolved, whether a physical or emulated device is required, possible side effects, or what happens if device is left empty. This is thin for an action-performing tool.

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 a single concise sentence that front-loads the action and then immediately gives useful, high-signal examples. Every part earns its place, and there is no filler or repetition of the 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?

Although the tool is simple, the device parameter is left completely undocumented and the description gives no guidance on multi-device situations or how the empty default behaves. The common-key list helps, but an agent still does not have enough context to confidently invoke the tool across different device setups.

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 0%, so the description must compensate. It adds useful common values for the key parameter, but it does not explain the device parameter at all, nor does it specify the exact accepted key syntax or whether values need to be exact strings. The parameter meaning is only partially clarified.

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 names the action ('Press') and the resource ('hardware or system key'), and provides concrete examples like back, home, recents, enter, delete, and volume_up. This helps distinguish it from sibling input tools such as tap and type_text, though it does not explicitly contrast with them.

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 no guidance on when to use this tool instead of tap, scroll, type_text, or wake_screen. The example keys imply system-level use, but there are no explicit exclusions, prerequisites, or alternative routing, leaving the agent to infer usage from sibling names.

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