screenshot

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

No annotations are provided, so the description carries the full burden. It usefully discloses the coordinate conversion details (bounds_pt, px_per_pt and the formula), which is critical behavioral context. However, it does not explain the behavior of parameters like 'fresh' (caching), 'format', or 'max_dim', nor any side effects or permissions. The disclosure is partial.

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?

The description is three concise sentences. The first states the core action, the second provides the essential coordinate formula, and the third gives a usage guideline. Every sentence adds value and there is no wasted text.

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 parameters, no annotations, and no output schema, the description provides the most critical information (purpose and coordinate mapping) but leaves parameter semantics unexplained. It is enough for a basic screenshot use case but not fully complete for an agent to leverage advanced features like fresh or max_dim.

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. It only hints at the 'region' parameter via 'or a region, in points,' and the coordinate formula indirectly relates to that. It fails to explain 'fresh', 'format', and 'max_dim' parameters, which are left entirely to the schema (which offers little beyond names and default values).

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 clearly states the tool's purpose: 'Capture the screen (or a region, in points).' It uses a specific verb ('capture') and resource ('screen'), and the parenthetical 'or a region' distinguishes it from screen-wide capture tools. This is distinct from sibling tools like get_ui_tree or find_text.

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?

The description provides a clear usage directive: 'Take a screenshot before any coordinate action.' This tells the agent when this tool is appropriate. However, it does not explicitly mention when not to use it or name alternatives, so it falls short of a 5.

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