Screenshot the canvas or the app window

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavior — the image is scaled to fit `maxSize`, includes the background, and window capture is scoped to the app window — though it omits how the PNG is returned (inline data vs. file path).

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?

It is appropriately short and front-loads the output format and default, but the final clause ('a window id that window') is grammatically broken, which undercuts comprehension rather than serving conciseness. Two sentences, no padding, but one is unusable as written.

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 4 undocumented-in-schema parameters, no output schema, and a near-identical sibling (`get_screenshot`), the description should do more: it never states the return format or how this tool differs from its sibling. The parameter hints it does provide are the only reason this is not a 1.

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 carry the load, and it does explain three of four parameters: `ids` (the given layers), `window` (true = app window, or a window id), and `maxSize` (default 1600). `scale` is only implied via 'scaled to fit', and the window clause is garbled, so compensation is partial.

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 conveys the resource (a PNG capture of the page or given layers, or the app window) but writes it as a noun phrase rather than a specific action, and it does not distinguish this tool from the sibling `get_screenshot`, which appears to do something very similar. An agent can guess the purpose but cannot tell which screenshot tool to pick.

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 when-to-use guidance, no statement of how this differs from `get_screenshot` or `export`, and no conditions under which window capture is preferable to page capture. Usage context is left entirely to inference.

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