Resize the viewport

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

With no annotations at all, the description carries the full burden and does disclose the most important trait: this mutates the user's real window, not a sandboxed view, plus the reset escape hatch. It omits permission requirements, whether other tabs/windows are affected, and whether the change is visible to the user mid-call.

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?

Two sentences, no waste. The primary behavior and units are front-loaded, and the cleanup instruction is placed second where an agent will read it before finishing.

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?

For a mutation tool with no annotations and no output schema, the description covers the essential behavioral facts (what is changed, in what units, and how to undo it). The unexplained tabId parameter and unstated multi-tab scope are the remaining gaps.

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 only 25% (reset only). The description compensates for width/height by specifying CSS pixels and example values, and reinforces reset's purpose, but tabId is documented in neither the schema nor the description, leaving one of four parameters opaque.

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?

States a specific verb (set/resize) and resource (page viewport) with the unit (CSS pixels) and a concrete example (375×812 mobile layout). This is unmistakably distinct from siblings like browser_scroll or browser_screenshot without opening any schema.

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?

Gives clear usage context ('to check a mobile layout') and an explicit follow-up directive ('call with reset: true when done'). It does not name alternative tools or state when not to resize, so it stops short of a 5.

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