Press a key

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

The description says what action is performed but not what effects it may have on the page (e.g., focus changes, event propagation, potential navigation). The annotations indicate non-read-only and non-destructive, but details of runtime behavior are not disclosed.

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 extremely concise and perfectly structured, using only necessary words and helpful examples. It is immediately scannable and free of extraneous information.

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 key-press operation, the description provides enough context to understand what the tool does. It does not mention return values or failure modes, but given the absence of an output schema and the simple nature of the action, this is acceptable.

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?

Both parameters are described: 'key' covers the target key or combined shortcut, and 'modifiers' explains extra modifier keys. Examples reinforce the expected format, though a full list of valid key names is not provided.

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 states the tool's purpose: pressing a key or modifier combo. Concrete examples (Enter, ArrowLeft, Control+A, Shift+Tab) remove ambiguity and distinguish it from mouse-based actions.

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 examples effectively illustrate typical keyboard inputs, but the description does not explicitly state when to prefer this over related actions like typing or clicking. It is still clear enough for common keyboard interaction scenarios.

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