scroll_until

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It adds valuable details: scrolling is one-viewport-page based, and it stops at the container boundary to avoid useless swipes. It does not mention behavior when max_scrolls is reached, but the stopping condition (scroll ends) is partially disclosed, making this a solid 4.

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 two sentences: the first defines purpose, the second adds a relevant behavioral detail. It is front-loaded, contains no filler, and every word contributes to understanding.

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?

Given the tool has an output schema and 80% parameter coverage, the description adequately covers the core purpose and stopping behavior. It does not explain return values (not needed) or explicitly mention max_scrolls interaction, but the 'or the scroll reaches its end' phrase covers the natural termination condition. A slightly more explicit note about what happens when the target is not found would elevate it, but it is sufficiently complete.

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 80%, so most parameters are already documented clearly. The description adds the concept of 'semantic target' which subtly enriches the target parameter by indicating it searches by text/desc/id, but this is marginal. It does not meaningfully compensate for the less-documented device/session parameters, so it stays at the baseline 3.

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 explicitly states 'Scroll until a semantic target appears' with a clear verb and resource, and adds a distinguishing behavioral detail ('one-viewport-page scrolling') that separates it from generic scroll_page or swipe tools. It also clearly conveys the stopping condition (target found or scroll ends), making the tool's purpose unmistakable.

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 implies when to use the tool: when you need to scroll to bring a semantic target into view. It provides context but does not explicitly name alternatives or exclusion criteria. Since it clearly states the primary use case without exclusions, it earns a 4 rather than a 5.

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