Press a key

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

Annotations already declare destructiveHint=true, idempotentHint=false, and readOnlyHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: the call synchronously returns the tree only after the application redraws, which tells the agent the response reflects post-keypress state.

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 tight sentences, front-loaded with the action and side effect, then the key vocabulary. The long enumeration earns its place because the schema has no enum constraint.

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?

With no output schema, the description correctly explains the return (the redrawn tree) plus the redraw side effect, and it covers the required key parameter. It stops short of explaining modifier semantics, which is the remaining gap for a 4-parameter tool.

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 only 25% and the schema defines no enums, so the description usefully supplies the full valid key vocabulary (enter, tab, esc, ... f1–f12) that the schema itself omits. It says nothing about the alt/ctrl/shift modifiers, leaving a quarter of the parameters undocumented in both places.

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 precise verb+resource: 'Sends one key press to the focused widget,' which is clearly distinct from a string-typing sibling like type_text. However, it never names or contrasts against the closest siblings (type_text, click), so an agent must infer the boundary.

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 implied rather than stated: 'to the focused widget' hints that a widget must be focused first, but there is no explicit when-to-use, when-not-to-use, or alternative (type_text/click/wait_for) mentioned.

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