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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=false and destructiveHint=false, but the description adds genuinely useful behavior: a real Chrome session with the user's own logins, URL routed to the site's existing tab before a new one so the user's tabs are preserved, and a page-content response. That side-effect and return information is not derivable from the annotations, and nothing contradicts them.

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 the action and the 'call it first' directive, then tab behavior, then the return shape. The clipped sentence style is slightly terse and the trailing Holded action list is context rather than definition, but every sentence carries information.

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?

There is no output schema, and the description compensates by saying what comes back ('the elements and text in view, with the same numbers'). With annotations covering safety and a fully documented two-parameter schema, the only meaningful gap is the unstated relationship to cotlet_browser_navigate.

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 description coverage is 100%, so both `url` and `app` are already documented in the schema, including the leave-it-out rule for `app`. The description adds only the routing behavior of the URL (existing site tab vs new tab), which is helpful but does not extend parameter meaning much past the schema baseline.

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 and resource: it starts the user's Cloud Browser (a real Chrome on Cotlet, signed in) and opens `url`, and it also returns the page contents. That is concrete and distinguishable from most siblings, though it never contrasts itself with cotlet_browser_navigate, so an agent must guess which of the two drives navigation.

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 an explicit ordering rule ('Call it first'), which is real when-to-use guidance, plus an inline rule for the `app` parameter (omit unless cotlet_app_guide names an app's own Cloud Browser). It stops short of stating when not to use it or which sibling takes over once the browser is already open.

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