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Docs/Guides/Migration from v1

Migration from v1

Upgrading from MobileBuildMCP 1.x to 2.x. Two breaking changes; most users only need the first.

The short version#

1. Append mcp to your server launch command#

MobileBuildMCP 2.x is a CLI first. To start the MCP server you must pass the mcp subcommand:

shell
# v1.x
npx -y mobilebuildmcp@latest

# v2.x
npx -y mobilebuildmcp@latest mcp

If you added the server via a CLI command, remove and re-add:

shell
# Claude Code
claude mcp remove MobileBuildMCP
claude mcp add MobileBuildMCP -- npx -y mobilebuildmcp@latest mcp

# Codex CLI
codex mcp remove MobileBuildMCP
codex mcp add MobileBuildMCP -- npx -y mobilebuildmcp@latest mcp

If you manage the config file directly, add "mcp" as the last entry in the args array.

2. Check your workflow configuration#

In v1.x, all workflows loaded by default. v2.x defaults to loading only the simulator workflow to keep the agent's tool schema footprint small.

Already set enabledWorkflows or MOBILEBUILDMCP_ENABLED_WORKFLOWS? Nothing changes.

Relied on the default? Your agent will now only see simulator tools until you opt in to additional workflows:

yaml
# .mobilebuildmcp/config.yaml
schemaVersion: 1
enabledWorkflows:
  - simulator
  - ui-automation
  - debugging

See Workflows for the full list.

Detailed reference#

MCP server launch requires the mcp subcommand#

Wherever your v1.x setup invoked mobilebuildmcp (or npx -y mobilebuildmcp@latest), append mcp so the final token is mcp.

Common config file locations:

ClientFile
Claude Code~/.claude.json
Claude Desktop~/Library/Application Support/Claude/claude_desktop_config.json
Cursor (project).cursor/mcp.json
Cursor (global)~/.cursor/mcp.json
VS Code (project).vscode/mcp.json
VS Code (global)~/Library/Application Support/Code/User/mcp.json
Windsurf~/.codeium/windsurf/mcp_config.json
Trae~/Library/Application Support/Trae/User/mcp.json
Codex CLI~/.codex/config.toml

JSON example:

json
"MobileBuildMCP": {
  "command": "npx",
  "args": ["-y", "mobilebuildmcp@latest", "mcp"]
}

TOML example (Codex CLI):

toml
[mcp_servers.MobileBuildMCP]
command = "npx"
args = ["-y", "mobilebuildmcp@latest", "mcp"]

Why default workflows changed#

In v1.x, all workflows loaded by default, exposing 70+ tools. Every tool definition and its schema is sent to the LLM on each turn, consuming context window space throughout the session. While most providers cache these tokens to reduce re-inference cost, they still occupy context that could otherwise be used for your code and conversation.

v2.x defaults to the simulator workflow. Other workflows (ui-automation, debugging, device, macos, swift-package, and more) are opt-in. Enable only what you need, when you need it.

Enabling additional workflows#

Config file (recommended):

yaml
schemaVersion: 1
enabledWorkflows:
  - simulator
  - device
  - macos
  - ui-automation
  - debugging
  - swift-package

Environment variable:

json
"MobileBuildMCP": {
  "command": "npx",
  "args": ["-y", "mobilebuildmcp@latest", "mcp"],
  "env": {
    "MOBILEBUILDMCP_ENABLED_WORKFLOWS": "simulator,device,macos,ui-automation,debugging,swift-package"
  }
}

New in v2: CLI and skills#

CLI mode#

The same mobilebuildmcp binary is now a CLI first. You can invoke tools directly:

shell
npm install -g mobilebuildmcp@latest

mobilebuildmcp tools
mobilebuildmcp simulator build-and-run --scheme MyApp --project-path ./MyApp.xcodeproj
mobilebuildmcp simulator screenshot
mobilebuildmcp ui-automation snapshot-ui --simulator-id <UDID>
mobilebuildmcp ui-automation tap --simulator-id <UDID> --element-ref e12

See CLI for the full guide.

MCP vs CLI for agents#

The MCP server remains the recommended way to use MobileBuildMCP with an agent. The CLI is provided as an alternative for scripting, CI, and direct terminal use.

Why MCP is preferred:

  • Automatic tool discovery: tools are registered with the agent at session start.
  • Session defaults: the server maintains stateful defaults across tool calls, so the agent doesn't re-supply project details on every invocation. Significantly reduces errors.
  • Stateful operations: log capture, debugging sessions, and other long-running operations are managed by the server.

The CLI avoids the per-turn context cost of MCP tool definitions, but loses session defaults and forces the agent to pass every parameter on every call. In practice, agents use MCP more reliably.

Agent skills#

v2 introduces two optional agent skills that prime the agent with usage conventions:

  • CLI Skill: strongly recommended when using the CLI with an agent.
  • MCP Skill: optional when using the MCP server.

Install:

shell
mobilebuildmcp init

See Agent Skills for flags and supported clients.

New in v2: project config#

v2 adds support for a project-local config file at .mobilebuildmcp/config.yaml. It replaces the need for scattered environment variables and gives you deterministic, repo-scoped behavior. Env vars still work but the config file takes precedence.

yaml
schemaVersion: 1
enabledWorkflows: ["simulator", "debugging"]
sessionDefaults:
  workspacePath: ./MyApp.xcworkspace
  scheme: MyApp
  simulatorName: iPhone 17 Pro

Create or update it interactively:

shell
mobilebuildmcp setup

See Configuration for the full schema.

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