app_type

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

With no annotations provided, the description carries the burden of behavioral disclosure. It discloses that typing targets the currently focused control and supports Unicode characters, which is meaningful. It does not, however, mention what happens if the window is not found, whether the window is activated, or any waiting/error behavior.

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 compact and front-loaded with the primary action, followed by a brief mechanism, a prerequisite, and parameter definitions. Every sentence earns its place and no unnecessary filler is present.

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 two-parameter tool, the description covers the core action, mechanism, prerequisite, and parameter semantics. Because an output schema exists, the agent does not need the description to explain return values. It could still note error conditions, but the current information is sufficient for correct invocation in most cases.

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 define the parameters itself. It does this for window_title by adding 'Full or partial window title (case-insensitive)' and for text by stating 'The text to type.' This adds value beyond the bare schema property names, though the text description is largely tautological.

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 opens with a specific verb and resource: 'Type text into a Windows application window.' It further clarifies the mechanism ('Sends Unicode characters to the window's currently focused control') and distinguishes itself from sibling tools like adb_type_text by explicitly scoping to Windows applications. This makes the tool's purpose unambiguous.

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 gives a clear prerequisite for correct use: 'Click on a text field first with app_click to focus it.' This tells an agent the required preceding action. It does not explicitly enumerate exclusions or alternatives, but the Windows-focused context makes the intended use clear.

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