Open a URL / deep link

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

No annotations are provided, so the description carries the full behavioral disclosure burden. It conveys the target scope (booted simulator) and the nature of the action (opening a URL), but it does not state what happens with an unhandled or malformed scheme, whether the handling app is launched as a side effect, or what a successful or failed invocation 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 a single, focused sentence that immediately states the action and target before providing a usable example. It contains no filler, front-loads the essential information, and is appropriately sized for a one-parameter tool.

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 one-parameter action tool with no annotations and no output schema, the description covers the core behavior and precondition but leaves edge cases uncovered—invalid schemes, fallback behavior, and what the caller should expect afterward. It is adequate but not comprehensive.

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 coverage is 0%, meaning the 'url' property is otherwise undocumented. The description adds real meaning by suggesting the expected format through examples like 'exp:// deep link or custom scheme'. This compensates somewhat, but it still leaves the full set of accepted schemes and any format restrictions unspecified.

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 specific verb plus resource ('Open a URL') with an explicit scope ('on the booted simulator') and grounding examples (exp:// deep link or custom scheme). This clearly distinguishes it from siblings such as launch_app, open_app, and open_storybook, which open applications rather than URLs.

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 the main use case through examples like exp:// deep links and custom schemes, and it hints at a precondition with 'booted simulator'. However, it never explicitly says when to prefer this tool over alternatives or names sibling tools as fallbacks, so the roadmap selecting between open_url and open_app/launch_app is left to inference.

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