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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=true. The description adds valuable behavioral detail beyond that: elementId requires observationId, calls with no scroll target are invalid, and numeric inputs are bounded. It still omits some side-effect context, but it meaningfully exceeds the annotation coverage.

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 description is front-loaded and compact, with four sentences that each carry invocation constraints or validation information. It avoids wasted prose, though the repeated INVALID_ARGUMENT phrasing is slightly verbose.

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?

For a 10-parameter tool with no output schema and very low schema description coverage, the definition covers the main scrolling modes and validation rules. It remains incomplete because amount is undocumented and the interaction between coordinate, delta, direction, and elementId modes is left mostly implicit.

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 only 10%, so the description needs to compensate. It covers direction values, elementId/observationId dependency, and numeric bounds for x, y, deltaX, and deltaY, but it never mentions the amount parameter and does not explain the distinct semantics of x/y versus deltaX/deltaY.

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 gives a specific verb and resource: scroll the page or a semantic element into view. It is immediately distinguishable from siblings like browser_click, browser_navigate, or browser_observe without needing schema inspection.

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?

It explains how to invoke scrolling with direction, deltas, coordinates, or elementId, and notes the observationId dependency. However, it does not say when to use this tool versus alternatives such as browser_observe or browser_wait, nor does it describe when not to use it.

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