iOS Simulator MCP

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

Annotations indicate readOnlyHint=false and openWorldHint=true, suggesting this is a mutable, open-ended operation. The description adds that it 'Opens the iOS Simulator application', implying it launches the simulator app, which provides useful context beyond the annotations. However, it doesn't detail side effects, error conditions, or what 'open' entails behaviorally (e.g., if it waits for boot).

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, clear sentence with no wasted words. It's front-loaded with the core action ('Opens'), making it easy to scan and understand quickly. This is an excellent example of concise and well-structured tool documentation.

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 has no parameters, no output schema, and annotations provide some behavioral hints, the description is minimally adequate. However, for a tool that likely interacts with a complex system like iOS Simulator, it could benefit from more context on what 'open' means operationally or typical use cases, leaving some gaps in 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?

With 0 parameters and 100% schema coverage, the input schema fully documents the lack of parameters. The description doesn't need to add parameter details, so it meets the baseline for this scenario. It doesn't introduce unnecessary parameter information, which is appropriate.

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 action ('Opens') and target resource ('the iOS Simulator application'), making the purpose immediately understandable. However, it doesn't explicitly differentiate from sibling tools like 'launch_app' or 'get_booted_sim_id', which might also involve simulator interaction, so it misses the highest score.

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. For example, it doesn't specify if this is for initial simulator startup versus other simulator-related operations, or mention prerequisites like needing Xcode installed. This leaves the agent with minimal context for decision-making.

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