Configure this session for visual QA

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

The description clearly discloses that updates apply to the session and future popups while preserving cookies, storage, privacy rules, and other sessions. It also warns that changing settings may trigger page actions and that the observation baseline remains unchanged, which aligns with the non-readOnly annotation.

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 information-dense, covering get/update semantics, persistence, side effects, policy behavior, and follow-up verification without unnecessary filler. It is well-structured and easy to parse.

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 simple scope and complete input schema, the description provides enough context for correct usage, including the return value ('Returns environment') and the important follow-up action (browser_verify). No critical behavioral gap is left unexplained.

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?

Every parameter is documented in the schema: viewport has width/height constraints, colorScheme and reducedMotion have enums, and sessionId explains the default behavior. The description of CSS/matchMedia exposure adds meaningful context beyond basic names.

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 title and description clearly state that this tool gets or updates the session's viewport, colorScheme, and reducedMotion for visual QA. It explicitly distinguishes read vs. update behavior and names the exact settings involved.

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 explains when to use the tool (responsive, light/dark, motion QA), how omitted settings behave, when it only reads, and that browser_verify should be called after updates. It also notes that updates are refused under readonly policy, giving clear usage boundaries.

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