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

Adds real behavior beyond annotations: the browser has an isolated profile, the call returns page elements/headings/scroll/screenshot, and recording does not begin until screen_record_start. Missing details on the relationship to screen_act and whether the browser session persists after the 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?

Front-loaded with what the tool does and its return shape, then param notes. The width/height/scale arithmetic example is a bit parenthetical but earns its place; no filler sentences.

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?

No output schema, but the description compensates by summarizing the return payload (elements with refs, headings, scroll, screenshot). Adequate for an 8-param open tool, with the main gap being the undocumented 'where' parameter.

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?

With 0% schema coverage across 8 params, the description carries the load well: it explains width/height as CSS pixels and the scale multiplier (1280x720 at 1.5 = 1920x1080), plus cursor (next page) and fields (dotted paths). It omits any meaning for 'where' and 'url', leaving two parameters unexplained.

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?

Specific verb+resource: opens a web page in a dedicated browser on the user's computer, and clarifies it uses its own profile rather than the user's sign-ins, which distinguishes it from screen_open_app and screen_login. Doesn't explicitly name the sibling it replaces, but the browser-vs-app boundary is inferable.

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?

Implicitly tells you this is the entry point for browsing ('Nothing is recorded until screen_record_start' signals the follow-up recording tool), but gives no explicit when-to-use guidance against screen_open_app or screen_login, nor prerequisites like whether login is needed first.

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