list_windows

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

With no annotations, the description carries the full burden. It discloses that only visible windows are listed (not hidden ones), provides the output structure (hwnd, title, process_name, etc.), and implicitly indicates a read-only operation. It does not discuss edge cases or permission requirements, but for a simple list operation this is adequate.

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?

Two sentences, front-loaded with the core action. The first sentence states the action and scope; the second lists return fields and gives a usage hint. No fluff 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 no-parameter, read-only tool with an output schema, the description is complete: it states purpose, output fields, and a usage pointer. It doesn't cover error cases or limitations (e.g., what happens if no windows are visible), but those are minor for a simple enumeration tool.

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 tool takes zero parameters, so the schema already trivially covers 100%. The description enhances understanding by explaining what the returned fields mean and how to use the primary output (hwnd), which is effectively the tool's 'parameter' for downstream tools.

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 action ('List all visible windows') and scope ('on the desktop'). It distinguishes itself from siblings like list_monitors and list_processes by specifically enumerating windows and explicitly returning window handles (hwnd) for use by other window tools.

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 implies when to use it: 'Use hwnd to identify a window for other window tools.' This gives clear context but does not explicitly mention alternatives or when not to use it. Since sibling tools like focus_window or close_window are well-differentiated, the context is sufficient.

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