key

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

No annotations are provided, so the description carries the full disclosure burden. It adds the focus-targeting rule and a useful tip about arrows driving custom dropdowns, but says nothing about return values, whether the press waits for effects, or how failures/no-op keys are reported.

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?

Two short sentences, front-loaded with the action and key set, then the focus rule and the cross-reference. No filler or redundancy.

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 7-parameter, no-annotation, no-output-schema tool, the schema is thorough and the description covers the common case. However, it omits outcome/error behavior and any indication of what a call returns, leaving an agent to guess about failure handling.

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 100%, and every parameter (key, ref, real, tabId, repeat, spaceId, snapshotId) is documented in the schema itself. The description restates the key values and focus behavior already covered there, so it adds no syntax or format detail beyond the structured fields.

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?

States a specific verb and resource ('Press a key') and enumerates the supported key classes: Escape/Enter/Tab/arrows, Backspace/Delete, and modifier combos. It closes by naming the sibling it is not ('For entering text use type'), so an agent can separate it from `type` without opening either schema.

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?

Gives clear routing context: 'Without ref it goes to whatever is focused' and 'For entering text use type.' That is an explicit alternative for one case, but it doesn't cover other plausible confusions (click vs key, select vs arrow keys, or when to prefer key sequences over repeated calls).

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