type

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

With no annotations, the description carries the full burden and does disclose key behavioral traits: it appends to existing text and requires a focusable element. It omits details like error handling or waiting behavior, but for a typing tool these are minor, so it is strongly transparent.

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 two concise sentences: the first states the core function, the second gives the alternative. It is front-loaded and contains 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 simple three-parameter tool with no output schema or annotations, the description sufficiently covers the action, the alternative, and a key requirement (focusable element). Extra details like auto-wait would add value but are not essential given the low complexity and complete schema.

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?

The input schema already provides 100% coverage with per-parameter descriptions. The tool description re-emphasizes 'text' by explaining the appending behavior, but adds no new parameter-level meaning beyond what the schema already states. Baseline 3 is appropriate.

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 uses a specific verb ('Type') and resource ('focusable element'), and immediately distinguishes from the sibling tool 'fill' by noting that it appends rather than replaces. This is a clear, specific, and differentiator-rich purpose statement.

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 explicitly names 'fill' as the alternative for replacing an existing value, and states that 'type' appends. This provides clear when-to-use and when-not-to-use guidance, satisfying the explicit alternatives criterion.

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