Launch an installed app

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

With no annotations, the description must carry behavioral disclosure. It accurately conveys that launching starts an app and that args are forwarded after the bundle id, but it does not describe return behavior, failure modes, or prerequisites such as the simulator being booted. This is useful but incomplete.

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?

Two focused sentences, with the core action front-loaded and the optional-argument detail in the second sentence. No filler or repetition.

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 launch tool the essentials are present: what to launch, how to identify it, and how to pass extra args. However, with no output schema and no annotations, an agent is left without information about return values or failure conditions, and the need for a booted simulator is only implicit. Slightly more context would make it fully complete.

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 schema documents udid but leaves bundleId undocumented, and only 33% of properties have descriptions. The description compensates by explaining that the target is identified by bundle identifier and that args are appended after the bundle id, adding meaning to two of the three parameters.

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 'Launch an installed app in the simulator by bundle identifier,' giving a specific verb, resource, and mechanism. This clearly differentiates it from sibling tools like install_app, simulator_boot, and terminate_app, so an agent can select it without opening the schema.

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 phrase 'installed app' implies the prerequisite that the app must already be present, and the note that optional arguments are 'useful for UI-test/debug launch flags' gives a concrete use case. It does not explicitly name alternatives or state when not to use it, so it falls short of full routing guidance.

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