screenshot

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

With no annotations, the description carries the full burden and handles it well. It discloses the primary return format (inline PNG), the fallback behavior when image content is unsupported (temp PNG path), and the important restriction about Wraith blocking the tool after a secret fill.

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 compact and front-loaded. The main action appears first, followed by three specific, non-redundant behavioral details. Every sentence contributes useful information without filler.

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?

Despite having no output schema and no annotations, the description explains what the call returns in both supported SDK modes and notes a critical limitation. For a zero-parameter tool, this is complete enough for an agent to know what will happen and how to interpret 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?

The tool has zero parameters and the schema already reflects that completely. Since there are no parameters to describe, the baseline of 4 is appropriate, and the description does not need to add parameter-level detail.

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 opens with a clear verb and resource: 'Capture a screenshot of the current page.' This is unambiguous, but it does not explicitly differentiate from sibling tools like snapshot, so it falls at 'clear but no sibling differentiation.'

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 concrete use context: returning an inline PNG so a multimodal model can see the page and disambiguate by element indices. It also states a clear exclusion by noting that Wraith blocks the tool after a secret fill, though it does not name alternative tools or when to prefer them.

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