Open a URL / deep link

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

Annotations declare readOnlyHint=false with destructiveHint=false, so the agent already knows this is a non-destructive but state-affecting action on the simulator. The description adds the useful behavioral fact that it accepts deep links rather than plain web URLs, but says nothing about what happens on an unrecognized scheme, whether the call blocks, or what it returns.

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?

A single front-loaded sentence with a compact parenthetical that earns its space by giving three concrete URL examples. No filler, no restating of the title or annotations.

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 two-parameter tool with no output schema, the description covers what it does and the URL forms it accepts, and the schema documents the `device` default of "booted". It omits the most common operational pitfalls (target app not installed, unregistered scheme) that would let an agent interpret a failure without further exploration.

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 only 50% and the required `url` parameter has no schema description at all; the description compensates by spelling out the accepted URI forms (myapp://..., universal link, exp+myapp://...), which is exactly the meaning an agent needs to fill that field correctly. It stops short of noting encoding rules or whether an unregistered scheme is an error.

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 ("Opens") plus a resource ("a URL in the simulator") and then enumerates the three accepted URL forms (custom scheme deep link, universal link, Expo dev-client URL). This is far more informative than the name alone, though it never explicitly distinguishes itself from android_open_url beyond the obvious platform split.

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?

There is no explicit when-to-use guidance and no named alternative; the agent must infer that this is the way to hand a URL/deep link to an already-installed app, whereas ios_launch_app launches by bundle id. No prerequisite (simulator booted, app installed, scheme registered) or failure guidance is given.

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