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

Goes well past the annotations by disclosing the cost model ('every started minute of the session costs credits'), the session lifecycle ('ends when closed or 3 minutes after the last call'), the implicit lazy-load side effect, and the exact return payload (URL, title, at_top, at_bottom). These are operational facts an agent cannot get from readOnly/idempotent hints alone.

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?

One dense but front-loaded paragraph: mode enumeration first, then side effect/return, then billing. Every sentence carries information, though the billing clause is appended to a long sentence and could have been separated for scanability.

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 naming the returned fields and their meaning (at_top, at_bottom). Combined with the three-mode explanation and session-cost warning, 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 coverage is 100% so the baseline is 3; the description adds cross-parameter meaning the schema does not, namely that `screens` describes distance for the down/up modes while `element` selects the scroll-until-visible mode. It restates the 0.8 default and the direction set, which is mildly redundant with 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?

Starts with a specific verb+resource ('Scrolls the current page in the user's browser') and enumerates the three distinct modes of operation (by screens, to top/bottom, until element). An agent can distinguish it from siblings like cotlet_browser_read or cotlet_browser_navigate without opening any schema.

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 phrase 'Content that loads on scroll appears, and the next read lists it' effectively tells the agent when to use this tool (to reach lazy-loaded content, then call cotlet_browser_read). It does not explicitly name a when-not condition or state that element-based scrolling supersedes the screens/direction parameters, so the routing is clear but not exhaustive.

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