key

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

With no annotations, the description carries the burden of behavioral disclosure. It adds useful context: '+' combines modifiers, named keys are accepted, and ctrl-shortcuts may trigger third-party global hotkeys on macOS. However, it does not disclose whether the press is a tap that auto-releases, how repeat interacts with combinations, or what happens if the target app is not focused.

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 efficiently front-loaded with the core action, then adds syntax, named-key list, and a high-value macOS caveat. Every sentence contributes information needed to call the tool correctly, with no filler or repetition.

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?

Given the low complexity of a key-press tool, no output schema, and no annotations, the description covers the essential calling requirements: format, modifier combination, named keys, and platform caveat. The only noticeable gap is usage routing relative to sibling tools, but that is largely a usage-guidelines issue.

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 coverage is 100%, so the baseline is 3. The description adds real value beyond the schema by explaining the '+' modifier syntax, enumerating named keys, and giving concrete examples such as ctrl+c and command+shift+z. It does not elaborate on the repeat parameter beyond the schema's default, but that is a minor gap.

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 precise action and object: 'Press a key or key combination.' The key-combination syntax, named-key list, and examples make it immediately clear what this tool does and distinguish it from siblings like 'type' (text entry) and 'hold_key' (press-and-hold).

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 gives no explicit guidance on when to choose this tool over sibling tools such as type, hold_key, left_click, or scroll. It only provides in-tool syntax and a macOS preference rule; there is no exclusion or alternative routing, so an agent must infer when 'key' is appropriate.

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