phone_press_key

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

Annotations already disclose readOnlyHint=false, destructiveHint=true, openWorldHint=true, and idempotentHint=false, so an agent knows this is a mutating, potentially destructive action. The description adds no further behavioral context: it does not state what environment effects a key press may have, whether it requires an active device connection, or what happens if the key is invalid.

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 wasted words. However, it is under-specified for a tool with two parameters and missing schema descriptions, making it terse rather than optimally informative.

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?

The presence of an output schema means return values need not be explained, and the annotations cover safety traits like destructiveness and open-world behavior. Yet the description does not address the undocumented 'serial' parameter or clarify when this key-press tool should be used instead of other phone interaction tools, leaving a moderate completeness gap.

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 for parameter documentation. It only implies the required 'key' parameter by saying 'one named ... key' and does not describe the serial parameter at all. Because the enum values are self-descriptive (HOME, BACK, etc.), the description adds minor context but still leaves 'serial' unexplained.

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 and resource: 'Send one named Android navigation/editing key.' It clearly differentiates from siblings like phone_tap or phone_type_text by focusing on named Android key events. However, it does not explicitly name or contrast with those alternatives, keeping it short of a 5.

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?

There is no explicit when-to-use or when-not-to-use guidance. The phrase 'Send one named Android navigation/editing key' implies its general purpose, but it gives no condition for choosing this tool over phone_tap, phone_tap_element, or other interaction siblings. No alternatives or exclusions are named.

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