ios.list_simulators

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

With no annotations provided, the description carries the full burden. The word 'List' and the mention of 'xcrun simctl' imply a non-destructive read-only operation and give implementation context. However, it does not disclose potential environment requirements (e.g., Xcode/macOS), output format, or whether only booted simulators are included. The behavior is mostly obvious, but not fully detailed.

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 sentence that front-loads the operation ('List available iOS simulators') and adds a useful implementation detail ('via xcrun simctl'). Every word adds value, and there is no unnecessary expansion.

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 zero-parameter listing tool, the description is largely sufficient: the agent knows what the tool does and how it does it. It does not specify the exact return structure, but this is not necessary for a list operation and there is no output schema to contradict or clarify. Minor missing detail about environment prerequisites keeps it from a 5.

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 tool accepts zero parameters and the schema is an empty object with 100% coverage. Per the 0-parameter baseline, this score is appropriate; the description does not need to explain parameter semantics because there are none.

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 ('List') and the resource ('available iOS simulators'), and adds the implementation detail 'via xcrun simctl'. This distinguishes it from siblings like device.list_devices, ios.boot_simulator, and ios.shutdown_simulator by indicating a non-mutating enumeration of iOS simulator instances.

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: choose this tool when you need to enumerate available iOS simulators. However, it does not explicitly state when to prefer it over related tools like device.list_devices, nor does it mention any exclusions. The context is clear from the resource naming, but direct alternative guidance is absent.

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