AndroidBuilder MCP Server

An official Model Context Protocol (MCP) server that connects to running instances of MIT App Inventor, AndroidBuilder, Kodular, or Niotron, allowing LLMs to interact with the Designer and Blocks workspace in real-time via the Chrome DevTools Protocol.

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Features

Tool	Description
get_project_info	Project name, active screen, view mode, IDE type, URL
get_component_tree	Full component hierarchy (name, type, uid, children) from Designer
get_component_properties	All property values for a specific component
update_component_property	Set a property using 3-strategy fallback (GWT API → top-frame → DOM)
add_blocks	Inject validated Blockly XML into the Blocks workspace
get_blocks_xml	Export the current workspace as Blockly XML
clear_blocks	Clear all blocks from the workspace
switch_screen	Navigate to a different screen
list_screens	List all screens in the project
click_element	Click an arbitrary CSS selector on the IDE page

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Prerequisites

1. Node.js ≥ 18
2. Google Chrome / Chromium launched with remote debugging enabled

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Setup

1. Launch Chrome with Debugging Port

Windows (PowerShell / CMD):

chrome.exe --remote-debugging-port=9222

macOS:

/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --remote-debugging-port=9222

Open your IDE (androidbuilder.in, App Inventor, etc.) and load your project.

2. Configure MCP Client

Add this server to your MCP client configuration (e.g. claude_desktop_config.json):

{
  "mcpServers": {
    "androidbuilder-mcp": {
      "command": "node",
      "args": [
        "C:/Users/User/.gemini/antigravity-ide/scratch/androidbuilder-mcp/dist/index.js"
      ],
      "env": {
        "BROWSER_DEBUG_PORT": "9222",
        "ANDROIDBUILDER_DEBUG": "0"
      }
    }
  }
}

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Environment Variables

Variable	Default	Description
BROWSER_DEBUG_PORT	9222	Chrome remote debugging port
EVAL_TIMEOUT_MS	15000	Max ms to wait for page evaluation
ANDROIDBUILDER_DEBUG	0	Set to 1 to enable verbose stderr logging

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Tool Reference

get_project_info

No parameters required.

Returns:

{
  "projectName": "MyApp",
  "activeScreen": "Screen1",
  "isBlocksView": false,
  "isDesignerView": true,
  "ideType": "AndroidBuilder",
  "url": "https://androidbuilder.in/ode/..."
}

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get_component_tree

Parameter	Type	Required	Description
screenName	string	No	Screen to inspect (default: active screen)

Returns:

{
  "screen": "Screen1",
  "tree": [
    {
      "name": "Screen1",
      "type": "Form",
      "children": [
        { "name": "Button1", "type": "Button" },
        { "name": "Label1", "type": "Label" }
      ]
    }
  ]
}

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get_component_properties

Parameter	Type	Required	Description
componentName	string	Yes	Component name (e.g. Button1)

Note: Click the component in Designer view first to populate the Properties panel.

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update_component_property

Parameter	Type	Required	Description
screenName	string	Yes	Screen owning the component (e.g. Screen1)
componentName	string	Yes	Component name (e.g. Button1)
propName	string	Yes	Property name (e.g. Text, BackgroundColor)
propValue	string	Yes	New value (e.g. Hello, #FF0000)

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add_blocks

Parameter	Type	Required	Description
xmlString	string	Yes	Valid Blockly XML (must start with <)

Requires: Blocks view

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get_blocks_xml

No parameters. Exports current workspace as XML.

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clear_blocks

No parameters. Clears all blocks (irreversible via MCP).

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switch_screen

Parameter	Type	Required	Description
screenName	string	Yes	Target screen (e.g. Screen2)

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list_screens

No parameters. Returns all screen names in the project.

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click_element

Parameter	Type	Required	Description
selector	string	Yes	CSS selector of element to click

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Troubleshooting

Failed to connect to Chrome CDP

• Chrome was not started with --remote-debugging-port=9222
• Another process is using port 9222
• Check BROWSER_DEBUG_PORT env var

No active AndroidBuilder/App Inventor tab found

• Open a project in the IDE before calling any tool
• The IDE page must be fully loaded, not just navigated to

Component tree (.gwt-Tree) not found

• You are in Blocks view — switch to Designer view

Blockly is not available

• You are in Designer view — switch to Blocks view

Tools hang / timeout

• Increase EVAL_TIMEOUT_MS (default 15000ms)
• Reload the IDE page and try again

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Development

# Build
npm run build

# Run with debug logging
ANDROIDBUILDER_DEBUG=1 node dist/index.js

# Run with custom port
BROWSER_DEBUG_PORT=9223 node dist/index.js

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Supported IDEs

• AndroidBuilder
• MIT App Inventor 2
• MIT App Inventor (code)
• Niotron
• Kodular
• AppyBuilder

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License

MIT