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

With no annotations, the description carries the full behavioral burden, and it delivers by revealing the underlying mechanism (address-bar typing + submit) and the verification through Web Inspector, explicitly avoiding false success reports. It also discloses the auto-start session behavior, going well beyond a generic 'navigate to URL' description.

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?

Three compact sentences cover the core action, verification behavior, the preferred alternative, and prerequisites. There is no filler, and the most important purpose information is front-loaded.

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?

The description is largely complete given the absence of annotations and output schema: it covers purpose, mechanism, verification, the sibling alternative, and session prerequisites. It could be slightly more explicit about when exactly to fall back to this tool if ios_safari_navigate is unavailable, but the guidance is strong overall.

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 100%: url is described as 'URL to navigate to (include https://)' and udid as 'iOS device UDID'. The description adds no further parameter-level nuance, so the baseline of 3 is appropriate.

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 states a precise action — navigate Safari to a URL on an iOS device — plus the mechanism (address-bar type + submit) and a verification step via Web Inspector. It also differentiates itself from the sibling ios_safari_navigate by describing that alternative as CDP-based, so an agent can tell them apart.

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 explicitly says to prefer ios_safari_navigate for Safari and gives the reason (CDP-based, also cold-opens Safari), which effectively tells the agent when not to use this tool. It also states the prerequisite of an active iOS automation session and notes that one auto-starts if needed.

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