scroll_until_visible

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

With no annotations, the description carries the full burden and does add real context: the 0.80 visibility threshold, stepwise scrolling, and popup scoping. It is silent on what happens when the threshold is never reached, how max_scrolls interacts with the loop, and whether scrolling is reversible.

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?

Two short sentences, zero filler, with the core behavior and threshold front-loaded ahead of the sibling routing advice.

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?

An output schema exists so return values needn't be explained, but for a four-parameter inference-driven UI action with no annotations, the missing failure semantics and undocumented parameter meanings leave gaps an agent would need to guess at.

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 0%, so the description must compensate, but it never explains mode (browser vs desktop), direction, max_scrolls, or the format expected for target_description. Only the popup/browser scoping hints at any parameter's effect.

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+resource ('scroll in steps') with the exact success criterion (visual P(visible) >= 0.80), which immediately distinguishes it from deterministic scrolling siblings. An agent can tell what this does and how success is measured without opening the 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?

Explicitly points to browser_scroll as the alternative and gives the selection criterion ('deterministic scrolling without inference'), plus notes scroll scoping to an active popup. It stops short of an explicit 'use this tool when...' statement, leaving the inverse condition to be inferred.

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