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

Beyond the annotations, the description discloses meaningful behavior: the target is a real Chrome session where the user is already authenticated, the URL reuses the site's existing tab or else opens a new one so the user's own tabs are preserved, and the call answers with the page's visible elements and text using the same numbering. That is substantive context the readOnly/openWorld hints do not convey.

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?

The imperative 'Call it first' is front-loaded, followed by environment, tab behavior, and return shape in a compact flow with no wasted filler. The closing list of Kahunas actions is compressed into a single sentence rather than prose.

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, so the description carries the return-value burden and does so ('the elements and text in view, with the same numbers'). Combined with the launch behavior, tab policy, and auth context, an agent has everything needed to call this correctly on the first attempt.

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 `app` and `url` are already well documented in the schema, establishing the baseline of 3. The description reinforces the default behavior (running in the user's own browser) but adds no format or constraint detail beyond what the schema's `pattern` and `format: uri` already state.

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?

The description states a concrete verb+resource: 'Starts the user's Cloud Browser ... and opens `url`', and clarifies the environment ('a real Chrome on Cotlet, where the user is signed in'). It also marks the tool as the entry point ('Call it first'). It stops short of explicitly differentiating itself from the `cotlet_browser_navigate` sibling, which an agent could otherwise confuse with opening a URL.

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 a clear ordering rule relative to the other browser tools, and the schema note plus description implicitly tell the agent to omit `app` for the normal path. It does not name an explicit alternative or when-not-to-use case (e.g., when a browser is already open, or how it differs from navigate), so guidance is clear but incomplete.

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