press_key

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states the action without revealing side effects (e.g., POWER may lock the screen, VOLUME_UP changes volume) or whether the key event is simulated. This minimal disclosure is a gap for a system-level action.

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, front-loaded sentence with no redundant words. It efficiently conveys the action and examples while remaining concise.

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 simple one-parameter action with no output schema, the description is largely complete. The schema fully documents the key parameter. The only omission is potential side effects of specific keys, but given the tool's simplicity, the description is adequate.

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 input schema already has 100% coverage with an enum and a description ('Key to press'). The tool description adds the phrase 'system key' and examples, but this is marginal and does not significantly enhance meaning beyond the schema, so the baseline of 3 is appropriate.

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 states a specific verb ('Press') and resource ('system key'), with examples (BACK, HOME, ENTER) that clarify the scope. This clearly distinguishes it from sibling tools like tap (which presses coordinates) and type_text (which sends text input).

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 implies when to use the tool (whenever a system key press is needed) but does not explicitly mention alternatives or exclusion criteria. It is adequate for a simple tool but lacks explicit guidance on when not to use it.

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