press_key

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

The description accurately describes the action as pressing a single key. No annotations are present, but the description provides enough behavioral context for a simple keyboard operation without misleading side effects.

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, well-structured sentence that immediately conveys the tool's purpose without unnecessary words.

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 tool with one parameter, the description sufficiently covers what the tool does. The output schema exists, so return value explanation is not required per rules.

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 provides only a 'key' string with no description. The description compensates with examples of valid keys (Enter, Escape, Tab, ArrowDown, a, etc.), giving meaningful guidance beyond the schema.

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 'Press a single key' with concrete examples like Enter, Escape, Tab, ArrowDown, a, etc. It distinguishes itself from siblings like type_text and click through the focus on individual key presses.

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?

While not explicitly stating when not to use, the description implies it is for single key presses, distinguishing it from multi-key or mouse actions. The examples help the agent understand appropriate usage.

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