snapshot_ui

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

With no annotations provided, the description partially carries the behavioral burden. It explains that the snapshot becomes stale after UI changes and must be refreshed, which is useful. However, it does not disclose the output structure, side effects, or any limitations beyond staleness.

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 a single dense sentence that front-loads the core purpose and packs in usage guidance. It is efficient but slightly run-on, and the unusual 'rs/1' phrase adds ambiguity. Overall, every phrase 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?

For a simple tool with one optional parameter and no output schema, the description covers the main workflow and refresh behavior. However, because there is no output schema, it would benefit from explicitly describing the snapshot format or the contents (e.g., the list of elementRefs) to fully prepare the agent.

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?

The only parameter 'sinceScreenHash' is fully described in the input schema (100% coverage), so the description does not need to add parameter details. Baseline of 3 applies because the schema provides complete semantics and the description offers no additional param context.

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 uses a specific verb ('Capture') and states the resource ('semantic rs/1 runtime UI snapshot with elementRef targets'). It clearly differentiates itself from sibling UI tools by emphasizing elementRef targets and the snapshot/observation role, not just describing the UI.

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 clear context: use the snapshot once, then use tap for a single target or batch for multiple same-screen targets, and refresh after navigation, scrolling, sheet changes, or layout changes. It implies when to use and when to refresh, though it does not explicitly name alternative tools or when not to use.

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