screenshot

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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It states the return format (base64 PNG) but does not explicitly mention that the operation is non-destructive, whether it captures the current viewport by default, or any permission requirements. The behavior is mostly obvious from the tool's nature, but the description adds limited context beyond the action itself.

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 a single sentence that is concise and to the point. It conveys the action, targets, and return format without any waste or redundancy. It is appropriately sized for a simple tool.

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?

Given the tool's simplicity and rich schema (which fully describes parameters), the description is mostly complete. It states the action, targets, and return format. However, it does not mention potential issues like whether fullPage works with popup/sidepanel targets, or error conditions. For a simple screenshot tool, this is nearly complete, but a small gap remains.

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 schema description coverage is 100%, so the baseline is 3. The description adds no additional parameter semantics beyond the schema; it merely repeats 'page, popup, or side panel' from the target enum. No extra context about fullPage behavior or parameter interactions is provided.

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 function with a specific verb ('Take a screenshot') and identifies the resources (page, popup, side panel). It also distinguishes this tool from siblings since no other sibling mentions screenshots. The return format (base64 PNG) adds clarity.

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 implies usage through its clear purpose, but it does not explicitly state when to use this tool versus alternatives. There are no alternative screenshot tools among siblings, so the usage is self-evident, but the description lacks explicit guidance or exclusions. The 'target' parameter is mentioned in the description, which hints at use cases, but no when-not guidance is provided.

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