screenshot

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

With no annotations, the description carries the full burden. It does disclose one important behavioral gotcha — that zoomed coordinates still map to full-screen coordinates for subsequent actions — which is real value beyond the schema. But it says nothing about the returned artifact (image format, resolution, how the agent consumes it), leaving a meaningful gap for an unannotated tool.

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 compact sentences with the core action front-loaded and the coordinate caveat placed where it matters. Efficient, though the second clause is slightly run-on and could be split for clarity.

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?

No output schema and no annotations mean the description is the only source of truth, and it omits any description of the return value or default full-screen behavior. Parameter semantics and the coordinate caveat are covered, but the definition is not fully self-sufficient for an agent deciding how to consume the result.

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 compensate, and it does name all four params, labels them as screenshot coordinates, and explains their combined effect (region zoom). It stops short of stating units or that the four should be supplied together, so not a full 5.

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?

"Capture the screen" is a specific verb+resource that an agent can immediately match to a screenshot operation. It does not explicitly differentiate from siblings like ui_tree or screen_info, which also expose screen state, so it falls short of a 5.

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 an implied use case for the optional region args ("zoom into a region for reading small text"), which is genuinely useful. However it never states when to prefer this over ui_tree/screen_info or that the no-arg form is the default whole-screen capture, so usage remains inferential.

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