set_viewport

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

No annotations are provided, so the description must disclose all behaviors. It mentions re-inspecting after setting the viewport but does not explain side effects (e.g., whether the page reloads, if other state is affected) or any constraints like permissions or rate limits.

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 concise and front-loaded with the main action. Every sentence adds value: the action, use cases, and follow-up steps. No fluff.

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 no output schema, the description logically explains the tool's purpose and suggests next steps. It covers the key aspects for an agent to use the tool effectively, though more detail on return behavior would be beneficial.

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 coverage is 100%, so the schema already describes the parameters. The description only mentions the optional 'deviceScaleFactor' and does not add meaning beyond the schema's default value of 1. Baseline 3 is appropriate.

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 emulates a viewport size and re-inspects, with specific verb 'Emulate' and resource 'viewport on the connected tab'. It provides concrete examples of responsive bugs, distinguishing it from sibling tools that focus on elements or styling.

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 explicitly says 'Use for responsive bugs' and gives examples like 'it breaks on mobile'. It suggests following with page_snapshot or explain_styles, providing clear context. However, it does not list alternatives or cases where this tool should not be used.

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