rn-device-mcp

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List iOS simulators

ios_simulators

Read-only

Lists iOS simulators with runtime, state, and UDID, showing booted devices first and optionally including simulators whose runtime is missing.

Instructions

Lists simulators with runtime, state and udid; booted ones first.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "ios_simulators"
  }
}

Input Schema

Name	Required	Description	Default
`includeUnavailable`	No	Include simulators whose runtime is missing

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 4, 2026

TDQS

B3.4/5.0

Behavior3/5

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

The annotations already establish that this is a read-only, non-destructive operation, so the safety profile is covered. The description adds useful behavioral detail that booted simulators are sorted first and that runtime, state, and udid are included, but it does not clarify the default treatment of unavailable simulators or what state values may appear.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single compact sentence that front-loads the main action and includes the most useful ordering detail. There is no redundant or filler wording.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only listing tool with one optional, well-documented parameter and no output schema, the description is largely complete. It states what is returned and how results are ordered, though it could note that unavailable simulators are excluded by default to fully complement the schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The sole parameter, includeUnavailable, is fully documented in the schema with a clear description. The tool description adds no further meaning about this parameter, but with 100% schema coverage the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a specific verb and resource ("Lists simulators") plus the returned attributes (runtime, state, udid) and ordering (booted first). It does not explicitly distinguish this from sibling listing tools like android_devices, but the iOS simulator scope is clear from the name and title.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no explicit when-to-use guidance, no mention of alternatives such as ios_boot or android_devices, and no prerequisites. Usage is only implied by the act of listing simulators, so an agent must infer that this is a discovery step before booting, shutting down, or installing to a simulator.

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