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

Goes well beyond the annotations by disclosing the credit cost model ('every started minute costs credits') and the session lifetime ('ends when closed or 3 minutes after the last call'), plus lazy-load behavior and return values. The readOnly annotation is not contradicted; a description this rich for a browser action is above average, though it could clarify whether scrolling alone can trigger state changes on infinite-scroll forms.

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 the action and mechanism, then modes, then side effects and returns. Dense but every clause carries information; the middle sentence is long but not padded.

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 supplies the return shape (URL, title, at_top, at_bottom), the lazy-load side effect, and the cost/session lifecycle. An agent has everything needed to call and budget for this 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?

Schema coverage is 100%, so the baseline is 3, but the description adds the interplay between parameters — screens measured in viewport heights with the 0.8 default, direction down/up/top/bottom, and element-based scrolling until in view. This clarifies how the modes relate rather than just restating defaults.

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 (scrolls the current page) with the mechanism (mouse wheel, human-like) and the three scrolling modes. It is clearly distinguishable from siblings like cotlet_browser_click, cotlet_browser_press, and cotlet_browser_read.

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?

Implies the usage scenario well: 'Content that loads on scroll appears, and the next read lists it' tells the agent to scroll before reading for lazy-loading pages. It does not name explicit alternatives (e.g., use navigate to change pages), so it stops short of full routing guidance.

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