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

Annotations already declare readOnly, idempotent, non-destructive, open-world, so safety is covered. The description adds genuinely useful behavior beyond that: the output is a JPEG, and it captures only the *visible* part of the page (viewport, not full page), which an agent needs to know before attempting coordinate clicks.

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 short sentences, with what is returned front-loaded before the usage guidance. No filler or repetition of annotation facts.

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 parameterless, no-output-schema tool, this covers the essentials: format, viewport limitation, and how to consume the result. Minor gaps remain, such as whether scrolling (cotlet_browser_scroll) is needed to see the rest of the page and any image-size/compression caveats.

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 baseline is 4. The mention of x/y image coordinates is not a parameter of this tool but usefully explains how this tool's output feeds the click/drag siblings.

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 states precisely what comes back: a JPEG of the visible portion of the page. That implicitly distinguishes it from the text-oriented cotlet_browser_read, though it never names that sibling or uses an explicit verb like 'capture a screenshot'.

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?

It gives concrete when-to-use guidance ('boards, canvases, maps, charts and layout that the text does not show') and a follow-on workflow (click or drag using image x/y). It does not explicitly exclude text-only checks or point to cotlet_browser_read as the alternative, so it stops short of a full when/when-not statement.

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