key

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

Annotations already declare destructiveHint=true, readOnlyHint=false and idempotentHint=false, so the safety profile is covered structurally. The description adds the useful fact that input goes to the frontmost app, but never warns that arbitrary combos can destroy unsaved work (cmd+w, cmd+s) or that the target app must be focused first.

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, core action front-loaded, examples and the repeat parameter explanation placed after. No filler or repetition of the tool name.

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 two-parameter tool with no output schema, the description covers the action and both parameters adequately. However, for a destructive-annotated tool it lacks any caveat about irreversibility or the precondition that a target app be frontmost (a sibling, activate_app, exists for exactly that).

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, and it largely does: it gives the accepted combo syntax by example and explains that "repeat presses it several times". It omits the repeat bounds (1-50), which the schema does carry via minimum/maximum.

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 or combo, scoped to the frontmost app, with concrete examples ("cmd+s", "esc"). It clearly differs from click/drag/scroll siblings, but does not distinguish itself from "type" or "menu", which an agent could easily conflate with keyboard input.

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?

Usage is only implied by the shortcut examples ("cmd+s", "cmd+shift+t"), which suggest keyboard-shortcut invocation. There is no explicit when-to-use statement and no mention of the adjacent tools (type, menu, activate_app) that an agent might pick instead.

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