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, and the description adds non-structured context: this is a real Chrome where the user is signed in, the user's own tabs are preserved, and the page is answered after load. It does not discuss what happens on navigation failure or how long it waits for page load.

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 launch and ordering guidance before the tab and return-value details. The trailing Anaplan action list is useful for routing but is a flat enumeration that adds length without much structure; everything else is tight and earns its place.

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?

With no output schema, the description carries return-value burden and does so qualitatively ('the elements and text in view, with the same numbers'), which tells the agent to reuse element numbers in follow-up calls. What remains unstated is load/wait behavior and error cases, minor for a tool whose annotations already cover the safety profile.

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 earns a bump by explaining what the `url` parameter actually does downstream — it targets the site's open tab rather than always spawning a new one. The `app` parameter's meaning is left entirely to the schema, which is acceptable given its documented optionality rule.

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 plus resource ('Starts the user's Cloud Browser ... and opens `url`') with a clear scope statement that it launches the real Chrome environment the user is signed into. The tab-targeting behavior (existing tab for the site, else new tab) further distinguishes it from cotlet_browser_navigate and cotlet_browser_tabs.

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 explicit ordering guidance that selects this tool ahead of the rest of the browser family. It also conditions the optional `app` parameter on cotlet_app_guide naming an app's own Cloud Browser, which is real routing guidance. It stops short of explicitly naming when a sibling like cotlet_browser_navigate should be used instead.

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