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

Goes well beyond the annotations: it discloses the return payload (URL and title after selection), a hard refusal policy (card fields and account pages), and the billing/session model (credits per started minute, session ends on close or 3 minutes after the last call). None of this is available in the structured fields, and it is consistent with destructiveHint=true and openWorldHint=true.

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 short sentences, front-loaded with the action and addressing scheme, followed by return value, refusal, and cost. Dense and mostly waste-free, though 'as read lists it' is awkward phrasing and the billing sentence could be trimmed.

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, yet the description states the return value (URL and title) and covers refusal and cost, which is the bulk of what an agent needs. It omits failure behavior when the option label doesn't match an entry, but that is a minor gap for a 2-parameter tool.

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?

With 100% schema coverage the baseline is 3, but the description adds real meaning: the element parameter is tied to the 'element list of the current page,' and the option may be given as the label 'as read lists it' or as its value — a distinction the schema's bare 'The option.' does not convey.

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 (chooses) and resource (an option of a drop-down list on the current page) plus the exact addressing mechanism (element number in the element list, option label/value). This is clearly distinguishable from sibling tools like cotlet_browser_click or cotlet_browser_type, which do not target dropdown option selection.

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?

The description implies the use case (dropdown selection) and gives one explicit when-not: card fields and account pages are refused. However, it never names alternatives such as cotlet_browser_click for non-dropdown elements or cotlet_browser_read to inspect the element list first, so the agent must infer the boundary.

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