screenshot

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

No annotations exist, so the description carries the full behavioral burden. It usefully discloses the screen scope and the coordinate reference frame for other tools, but says nothing about the return value (image object, base64, saved path), multi-monitor behavior, or how the result is consumed downstream.

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, both load-bearing: the first defines the operation and scope, the second delivers the critical interoperability fact about the coordinate system. Nothing is padded.

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 zero-parameter capture tool the description covers what an agent most needs to know to use it in a workflow. The only real gap is the return format, which is not covered by an output schema.

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 there is nothing for the description to disambiguate; baseline 4 applies.

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 ("Take a screenshot") and adds scope ("of the whole screen"), so an agent knows this is a full-screen capture rather than a window or region grab. It does not explicitly differentiate from siblings, but no sibling performs capture, so ambiguity is low.

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?

Usage is only implied: the note that other tools' coordinates refer to this image hints that this should be called first to establish the coordinate frame, but the description never says when to call it, in what order relative to click/type_text, or whether it can be re-invoked mid-task.

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