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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds real behavioral value beyond that: the URL targets the site's existing tab or a new tab so the user's own tabs survive, the user is authenticated in this Chrome session, and the call returns the page's visible elements and text with stable element numbers.

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?

Four tight sentences, front-loaded with the core action and followed by tab behavior, return shape, and supported actions. The ChowNow action list is a long tail that is relevant to routing but adds bulk.

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 explaining what comes back (elements and text in view, with matching element numbers), which an agent needs for follow-up click/type calls. Combined with full schema coverage and annotations, the only real gap is failure/retry behavior.

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 parameters are already documented, including the conditional instruction to omit `app` unless cotlet_app_guide names an app's own Cloud Browser. The description adds only routing detail about where `url` lands and never discusses the `app` parameter, so it stays at the baseline for a fully documented schema.

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 session where the user is already signed in) and opens a URL. The phrase 'Call it first' implicitly separates it from cotlet_browser_navigate, but that sibling is never named, so the boundary is inferred rather than stated.

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?

'Call it first' gives an explicit ordering rule that tells the agent when to reach for this tool, and the ChowNow action list scopes a concrete use case. It stops short of exclusions, e.g. what to do if the browser is already running (presumably use cotlet_browser_navigate), which is left for the agent to deduce.

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