is

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

Since no annotations are provided, the description carries the full burden of behavioral disclosure. It adds a useful timeout detail (90s) and implies a read-only predicate check, but it does not disclose what happens on failure, whether the check waits/retries before returning, or what the response shape looks like.

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 with no filler. It front-loads the core purpose, then immediately provides the key usage alternative and the timeout constraint. 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?

For a tool with 23 parameters, no annotations, and no output schema, the description covers the essential core behavior and timeout but leaves gaps around return values, failure semantics, and how the many optional parameters affect resolution. The 87% schema coverage mitigates this, but the description is not fully complete on its own.

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 87%, so the optional parameters are mostly self-documenting. The description adds meaning to the two required parameters, `selector` and `predicate`, by explaining the relationship between them and listing example predicate values. This is helpful but does not go significantly beyond the schema's existing enum and structure.

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 tool's function: checking whether a selector satisfies a UI predicate, with concrete examples such as visible, hidden, editable, selected, focused, or text. It also distinguishes itself from the wait sibling by explicitly naming when wait should be used instead.

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 actionable guidance: use wait when the condition may appear asynchronously. This provides a clear alternative and condition for choosing between `is` and `wait`. However, it does not explicitly compare against other related siblings like `find` or `snapshot`, so usage context is good but not fully exhaustive.

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