screenshot

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

Annotations already mark the tool as destructive and non-read-only, so the description does not need to repeat that. It usefully adds that the output is a PNG saved to a path and can target an element. However, it does not mention potential overwriting of existing files or that full_page affects capture dimensions, leaving some behavior implicit.

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?

A single, front-loaded sentence conveys the core action, target, format, destination, and purpose with no filler. Every phrase earns its place, and the key information is immediately visible.

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 tool with three optional parameters and an output schema, the description gives the essential overview but omits important call details like full_page semantics and what happens when path is null. An agent could make a reasonable first attempt, but might mis-handle full_page or default path behavior without additional context.

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 input schema has zero description coverage, so the description must carry the burden. It does clarify path and selector ('to a path', 'page or one element'), but it does not explain the full_page parameter or the meaning/behavior of null defaults. This is partial compensation, not complete.

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 uses a specific verb ('Save'), identifies the resource ('page or one element'), specifies the output format ('PNG') and destination ('path'), and clarifies the intended audience ('for a human to look at'). This clearly distinguishes screenshot from sibling tools like outline, styles, or page_state, which serve different inspection purposes.

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 clear context: use this tool when visual evidence is needed for a human to review. It implies a distinction from machine-readable inspection tools, though it does not explicitly name alternatives or state when not to use it. The lack of explicit exclusions prevents a 5.

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