type

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

With no annotations, the description carries the full burden; it does disclose real constraints (1-1000 characters, printable ASCII only, requires a focused field). It omits error/failure behavior, whether text appends or replaces, and platform specifics, so coverage is partial.

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?

A single tight sentence that front-loads the action and constraints with no wasted words. Appropriately sized for the operation.

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?

An output schema exists, so return values need not be described, and length/charset constraints are stated. However, the required 'phone' argument is entirely unaddressed and there are no annotations, leaving the definition incomplete for correct invocation.

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. It implicitly covers 'text' (the characters typed) but says nothing about the equally required 'phone' parameter, leaving half the input contract unexplained.

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 specific verb (Type), resource (printable ASCII characters), and target (the focused field), which is concrete enough to picture the operation. It does not differentiate from the sibling 'key' tool, which likely handles individual keystrokes, leaving some ambiguity between the two.

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?

'Into the focused field' implies a prerequisite (something must already be focused), but the description never states when to use this over siblings like 'key', 'tap', or 'swipe', nor what to do if no field is focused. Usage is only weakly inferred.

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