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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=false, destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavior: the URL goes to the site's existing tab else a new one, so the user's own tabs are preserved, and it returns the page's visible elements and text using the same element numbering as the click/fill siblings. It does not mention authentication requirements, session lifetime, or failure modes.

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?

Dense but front-loaded: what it does, when to call it, and how the tab is chosen all appear before the trailing Boulevard action catalog. The app-specific enumeration is somewhat long relative to its decision value, but every clause 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?

No output schema exists, and the description compensates by describing the return payload (visible elements and text with the same numbering). For a two-parameter, non-required entry-point tool the coverage is strong; only retry/error behavior is unaddressed.

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 100%, so baseline is 3, but the description adds meaning the schema does not: the url target-tab resolution rule (existing site tab first, else new tab) and the fact that the open page is answered immediately with numbered elements. The app parameter's exclusion logic is also restated in prose, reinforcing the 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: starts the user's Cloud Browser (a real Chrome on Cotlet) and opens `url`. It also distinguishes itself temporally with "Call it first." It stops short of explicitly contrasting with cotlet_browser_navigate, so the boundary with that sibling is left implicit.

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 clear entry-point ordering, and the app-parameter guidance ("Leave it out... Only when cotlet_app_guide names an app's own Cloud Browser") tells the agent when not to override the default. The Boulevard action list supplies concrete usage contexts. No explicit statement of when to prefer cotlet_browser_navigate or cotlet_browser_read instead.

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