iOS Simulator MCP

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

Annotations indicate readOnlyHint=false (mutation) and openWorldHint=true (flexible environment), which the description aligns with by describing an installation action. The description adds context beyond annotations by specifying the target environment ('iOS Simulator') and file types (.app or .ipa), but does not detail side effects like overwriting existing apps, authentication needs, or error handling, keeping it from a perfect score.

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, front-loaded sentence that efficiently conveys the core purpose without unnecessary details. Every word earns its place, making it highly concise and well-structured for quick understanding.

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?

Given the tool's complexity (mutation with open-world hint), the description covers the essential action and environment. However, without an output schema, it lacks details on return values or success/failure indicators. The annotations provide safety and flexibility context, but more behavioral info (e.g., installation outcomes) would enhance completeness.

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%, with clear descriptions for both parameters (udid and app_path). The description does not add meaning beyond the schema, as it only mentions 'app bundle' without elaborating on parameter usage or constraints. Baseline 3 is appropriate since the schema adequately documents 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 clearly states the specific action ('Installs') and target resource ('an app bundle (.app or .ipa) on the iOS Simulator'), distinguishing it from siblings like launch_app (which runs an already installed app) or screenshot (which captures visual output). The verb+resource combination is precise and unambiguous.

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 usage when you need to install an app bundle on a simulator, but it does not explicitly state when to use this tool versus alternatives (e.g., launch_app for running apps, or other tools for simulator management). There is no guidance on prerequisites, such as needing a booted simulator, or exclusions, leaving usage context partially inferred.

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