focus_window

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

No annotations are provided, so the description carries the burden. It mentions the frontmost fallback behavior and return format (metadata or error), but does not disclose side effects (e.g., brings window to front, changes keyboard focus), permissions needed, or potential failure modes beyond an error message.

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 concise and front-loaded with the core purpose. Parameters and return value are clearly listed in a structured format. No unnecessary words or repetition.

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?

Given the three optional parameters and the existence of an output schema, the description covers the main functionality well. It explains the three ways to specify the target window and notes the return value. However, it could be strengthened by clarifying what 'focus' means in practice (e.g., bringing to front) and providing minimal usage 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?

Schema description coverage is 0%, but the description adds meaning for all three parameters: app_name (optional app name, bundle id, or process name), window_id (CoreGraphics id), and window_index (1-based index). It explains their optionality and default values, compensating for the schema's lack of inline documentation.

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 tool's purpose: 'Focus a macOS window by window id, app name, or frontmost fallback.' It specifies the verb (Focus) and the resource (macOS window), distinguishing it from siblings like move_window or resize_window.

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 provides no guidance on when to use this tool versus alternatives such as list_windows or minimize. It lists parameters but does not explain prerequisites or scenarios where one parameter combination is preferable over another.

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