XC-MCP: XCode CLI wrapper

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Install App on Simulator

simctl-install

Idempotent

Install built .app bundles to iOS simulators for testing. Provide simulator UDID and app path to validate and deploy in seconds.

Instructions

simctl-install

Install iOS apps to simulators for testing.

Overview

Installs a built .app bundle to a simulator device, making it available for launching and testing. Validates the app bundle format and simulator state before installation. Fast installation completes in seconds for quick test iterations.

Parameters

Required

udid (string): Simulator UDID (from simctl-list)
appPath (string): Path to .app bundle (e.g., /path/to/MyApp.app)

Returns

Installation status with app name, simulator info (name, state, availability), success indicator, command output, and guidance for next steps (launch, get container, uninstall).

Examples

Install from Xcode build output

await simctlInstallTool({
  udid: 'ABC-123-DEF',
  appPath: '/Users/dev/Library/Developer/Xcode/DerivedData/MyApp-xxx/Build/Products/Debug-iphonesimulator/MyApp.app'
});

Install to specific simulator

await simctlInstallTool({
  udid: 'TEST-DEVICE-UDID',
  appPath: '/path/to/MyApp.app'
});

simctl-launch: Launch installed app
simctl-uninstall: Remove app from simulator
simctl-get-app-container: Get app filesystem container path

Notes

App path must point to .app bundle (not .ipa)
Fast installation - completes in seconds
Validates app bundle format and simulator state
Extracts app name from bundle path automatically
Deploys built apps directly from Xcode DerivedData
Use for quick test iterations and automated test pipelines

Input Schema

TableJSON Schema

Name	Required	Description	Default
`udid`	Yes
`appPath`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Addedv4.1.0Sep 14, 2026

TDQS

A4.5/5.0

Behavior4/5

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

The description discloses that the tool validates the app bundle format and simulator state before installation, and that it extracts the app name automatically. It also states it is fast (completes in seconds). While annotations already indicate idempotentHint=true and destructiveHint=false, the description adds context about validation and speed, which is useful beyond the annotations. It does not mention permission requirements or reversibility, but given the annotation coverage, this is acceptable.

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 well-structured with clear sections (Overview, Parameters, Returns, Examples, Related Tools, Notes) and is appropriately sized. It front-loads the essential purpose and parameters, and each section adds value without redundancy. The examples are concrete and guide usage, making the description efficient and easy to scan.

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

Completeness5/5

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

The description is complete for an install tool: it covers the purpose, parameters, return value (installation status and next-step guidance), and usage context. It mentions that the tool supports deploying from Xcode DerivedData and is suitable for fast iterations, which is practical context. Given no output schema exists, the description's explanation of return data is sufficient. The related tools section also fills the context for subsequent actions, making the definition self-contained.

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 input schema provides only property names and types with no descriptions (0% schema coverage), so the description must compensate. The description explains that udid is the simulator UDID and appPath is the path to the .app bundle, with an example path. This adds necessary semantics beyond the bare schema, but it could be more explicit about the format of udid (e.g., how to obtain it from simctl-list) and the expected structure of the app bundle. Still, it meets the baseline for compensating for the schema gap.

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

Purpose5/5

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

The description clearly states the tool's function: installing iOS apps to simulators for testing. It specifies the resource (.app bundle) and the action (install), and distinguishes it from siblings like simctl-launch and simctl-uninstall by focusing on the installation step. The related tools section further clarifies its role in the workflow.

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

Usage Guidelines5/5

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

The description provides explicit guidance on when to use this tool: for installing built app bundles to simulators, specifically for quick test iterations and automated test pipelines. It also names related tools (simctl-launch, simctl-uninstall, simctl-get-app-container) and their purposes, implicitly directing agents to use them for subsequent steps. The notes clarify that app path must be a .app bundle, not .ipa, preventing common misuse.

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

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