Type

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

Annotations already indicate this is a destructive, non-read-only operation, so the description carries a lighter burden. It adds useful context about targeting modes (bound element vs scoped-app focused element), but does not disclose behaviors such as whether existing text is overwritten, whether keyboard events are simulated, or whether strategy defaults affect invocation. No contradiction with annotations.

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?

One sentence of 17 words with no filler. The core targeting distinction is front-loaded and easily parsed. It is concise and efficient, though it could have been slightly more structured to cover the coordinate mode without adding much length.

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?

The tool is relatively complex with 5 parameters, a nested target union, and multiple enum options, and there is no output schema to disambiguate behavior. The single-sentence description is insufficient on its own: it omits coordinate targeting, does not explain how target and app_ref interact, and offers no guidance on strategy or return_state. An agent would need to rely heavily on the schema and surrounding context.

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 description adds some meaning by relating 'bound element' to the element target and 'focused element of a scoped app' to the app-level targeting concept. However, it does not explain coordinate targets, the 'app_ref' parameter, or the 'strategy' and 'return_state' enums beyond what the schema already provides. With only 60% schema description coverage, the description compensates only partially.

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 clearly states the verb ('Type') and the resource ('text into a bound element or the focused element of a scoped app'), so an agent understands the primary function. It is distinguishable from key-press tools like 'key' and value-setting tools like 'set_value'. However, it omits the coordinate target mode present in the schema, slightly narrowing the expressed scope.

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?

There is no guidance about when to use this tool instead of alternatives, nor any mention of when not to use it. The description does not reference sibling tools such as 'key', 'set_value', or 'write_clipboard', and it fails to state preconditions like focus or accessibility requirements.

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