press_key

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

Without annotations, the description carries more burden and does provide useful behavior: it discloses that any KEYCODE_* name works and that the format is checked before the shell command is built. However, it does not mention potential side effects such as power toggling the screen, volume changes, or what happens on invalid input beyond validation. Behavioral disclosure is partial.

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 purpose is front-loaded in a single sentence followed by a compact list of accepted keys. Every sentence carries useful information, but the long enumeration could benefit from clearer grouping or bullet formatting.

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?

An output schema exists, so return values do not need to be described. The description is complete enough for the required key parameter and its validation, but it omits explanation of the serial parameter and when to prefer press_key over text/touch input tools. For a simple action tool, this is mostly adequate but not fully self-contained.

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 strongly documents the required 'key' parameter by listing valid shortcut names and the KEYCODE_* pattern, adding meaning beyond the bare string schema. The optional 'serial' parameter is never mentioned, which leaves multi-device targeting underspecified.

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 first sentence states a specific action: pressing hardware/system keys. The description then enumerates the exact accepted key names, making the tool's resource and scope clear. It is distinguishable from sibling touch/text tools like tap and type_text by the 'hardware/system key' framing.

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 guidance on when to use press_key versus siblings such as tap, type_text, or paste_clipboard. The description does not state exclusions, prerequisites, or device-targeting context. The only hint of usage is the implicit key list.

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