Scroll page

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

With no annotations provided, the description carries the full behavioral burden. It discloses coordinate frame semantics, iframe targeting, and the lazy-load limitation, which is meaningful. It does not mention side effects, scroll-triggered events, permissions, or what the tool returns after execution.

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?

Three dense sentences with no filler. The primary action and target are front-loaded, and the follow-up sentences add high-value coordinate and lazy-load caveats. Every sentence 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?

The description plus the rich schema cover target selection, coordinate spaces, snapshot options, wait conditions, and the key lazy-load caveat. The main gap is the absence of an output schema and no explicit contrast with collect_scroll, but the agent has enough to invoke the tool correctly.

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 75%, so the baseline is already moderate. The description adds important semantic detail beyond the schema, especially that x/y are tabViewport coordinates for the top document and frameViewport coordinates for an iframe, and clarifies documentId targeting. Remaining parameters are already well described in 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?

The description clearly states the action ('Scroll') and the resource ('current top document or an exact documentId') with pixel-delta detail. It doesn't explicitly differentiate from sibling collect_scroll, but the target and coordinate nuance make the purpose unambiguous.

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 gives a useful condition for effectiveness: 'scroll only helps when the page lazy-loads content' and suggests using textLimit on snapshots to capture more text. However, it does not name specific alternatives or give explicit guidance on when another tool like collect_scroll would be more appropriate.

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