Resize viewport

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

Annotations set destructiveHint=false and readOnlyHint=false, and the description simply states the action (resize) without adding deeper behavioral context. While it doesn't contradict, it also doesn't elaborate on potential side effects like impact on other tools or state persistence. With annotations carrying the safety profile, a score of 3 is appropriate.

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 efficiently conveys the purpose and a typical use case. Every word is meaningful and there is no excess 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?

Given the tool's simplicity (2 parameters, no output schema, no nested objects) and full schema coverage, the description is complete enough. It clearly explains what the tool does and offers a contextual example for when it is useful.

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 covers both parameters (width, height) with 100% description coverage, including units (px). The description adds no additional parameter details beyond the schema. As schema coverage is high, baseline score of 3 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?

The description clearly states the tool resizes the viewport, using a specific verb and resource. It also provides a concrete use case ('check a responsive breakpoint before screenshotting'), which distinguishes it from sibling tools like 'screenshot'.

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 gives a clear example of when to use the tool ('before screenshotting'), which implies context. However, it does not explicitly state when not to use it or mention alternatives, so it falls short of a perfect score.

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