iOS Simulator MCP

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

Annotations indicate readOnlyHint=false (implying mutation) and openWorldHint=true (suggesting flexible use), but the description adds minimal behavioral context. It mentions the launch mechanism ('by bundle identifier') but doesn't disclose side effects (e.g., app state changes), error conditions, or dependencies like simulator availability. No contradiction with annotations exists.

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, efficient sentence that front-loads the core purpose without unnecessary words. Every element ('Launches', 'app on the iOS Simulator', 'by bundle identifier') contributes directly to understanding, with zero waste or redundancy.

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 moderate complexity (mutating app state), lack of output schema, and annotations covering basic hints, the description is minimally adequate. It specifies the action and target but omits details on outcomes (e.g., success indicators), error handling, or integration with sibling tools, leaving gaps for an agent to infer.

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 each parameter well-documented in the schema (e.g., udid pattern, bundle_id example, terminate_running purpose). The description adds no parameter-specific semantics beyond implying bundle_id is the primary identifier. Baseline 3 is appropriate as the schema carries the full burden.

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 ('Launches') and target resource ('an app on the iOS Simulator by bundle identifier'), distinguishing it from sibling tools like install_app (which installs) or open_simulator (which opens the simulator itself). 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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing a booted simulator or installed app), exclusions, or comparisons to siblings like open_simulator or ui_tap for app interaction. Usage context is implied but not explicit.

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