list_windows

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new context beyond that: it reads metadata only, and on macOS window titles require Screen Recording permission — a real precondition an agent would not otherwise know.

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?

Three dense sentences, front-loaded with the action and return shape, followed by parameter meaning and a permission caveat. Slightly run-on in the first sentence but no wasted content.

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?

With no output schema, the description carries the burden of describing returns and does so: item fields, plus 'count, windows and a suggestion'. Combined with the permission note and the sibling reference, an agent has everything needed to call and consume this 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?

Schema description coverage is 100%, so the single parameter is already documented. The description restates the same case-insensitive substring semantics rather than adding format or edge-case detail, so it meets the baseline but no more.

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?

States a specific verb and resource ('List the visible windows') and immediately gives the return shape [{id, app, title, bounds}]. It also distinguishes itself from the sibling capture_window by naming it as the downstream consumer of the returned ids.

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?

Explicitly frames the tool's role: 'to get the id for capture_window', which tells the agent exactly why and when to call it. It stops short of stating when not to use it or what alternative to prefer for other listing needs, so it falls just below the top score.

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