IDB CLI Testing for Claude Code Mobile

Overview

Systematic UI automation using IDB CLI for Claude Code Mobile app testing.

Core principle: Use IDB accessibility tree to find elements by testID (AXUniqueId), extract coordinates, then interact. No guessing coordinates. No MCP dependencies.

When to use: xc-mcp unavailable, expo-mcp local tools unavailable, need autonomous Gate 4A testing

Prerequisites Check

# Verify IDB installed
which idb && which idb_companion

# Start idb_companion (if not running)
ps aux | grep idb_companion || idb_companion &

# Verify simulator booted
idb list-targets | grep Booted

# Verify IDB connected
idb list-apps --udid booted | head -5

Must show: IDB commands working, companion running, simulator booted

Core Workflow: Find by testID → Tap

Step 1: Get UI Tree with testIDs

# Get complete accessibility tree (includes all AXUniqueId = testID)
idb ui describe-all --udid booted > /tmp/ui-tree.json

# Or save to project
idb ui describe-all --udid booted > logs/ui-tree.json

Returns: JSON array of ALL UI elements with:

• AXUniqueId: The testID from React Native
• frame: {x, y, width, height} for tapping
• AXLabel: Visual label text
• enabled: Whether element is interactive
• type: Button, TextArea, StaticText, etc.

Step 2: Find Element by testID

Use jq to parse (or Python/Node.js):

# Find send-button testID
cat logs/ui-tree.json | jq '.[] | select(.AXUniqueId == "send-button")'

# Extract just coordinates
cat logs/ui-tree.json | jq '.[] | select(.AXUniqueId == "send-button") | .frame'
# Returns: {"x":350, "y":798, "width":36, "height":36}

Or find in output directly:

idb ui describe-all --udid booted | grep -A 3 '"AXUniqueId":"send-button"'

Step 3: Calculate Tap Coordinates

Tap at CENTER of element:

center_x = frame.x + (frame.width / 2)
center_y = frame.y + (frame.height / 2)

Example:

• Frame: {x:350, y:798, width:36, height:36}
• Center: x=368, y=816

Step 4: Tap the Element

# Tap send button (calculated center coordinates)
idb ui tap --udid booted 368 816

Verify with screenshot:

xcrun simctl io booted screenshot logs/after-tap.png

Complete Test Workflows

Test 1: Tap Message Input and Type

# 1. Get UI tree
idb ui describe-all --udid booted > logs/ui-tree.json

# 2. Find message-input coordinates
INPUT_COORDS=$(cat logs/ui-tree.json | jq -r '.[] | select(.AXUniqueId == "message-input") | "\(.frame.x + .frame.width/2) \(.frame.y + .frame.height/2)"')

# 3. Tap input field (split coordinates)
IDB_X=$(echo $INPUT_COORDS | cut -d' ' -f1)
IDB_Y=$(echo $INPUT_COORDS | cut -d' ' -f2)
idb ui tap --udid booted $IDB_X $IDB_Y

# 4. Type text
idb ui text --udid booted "Hello Claude"

# 5. Screenshot to verify
xcrun simctl io booted screenshot logs/message-typed.png

Test 2: Tap Send Button

# 1. Find send-button (same process)
SEND_COORDS=$(cat logs/ui-tree.json | jq -r '.[] | select(.AXUniqueId == "send-button") | "\(.frame.x + .frame.width/2) \(.frame.y + .frame.height/2)"')

# 2. Tap send button
idb ui tap --udid booted $(echo $SEND_COORDS | cut -d' ' -f1) $(echo $SEND_COORDS | cut -d' ' -f2)

# 3. Screenshot result
xcrun simctl io booted screenshot logs/message-sent.png

Test 3: Navigate to Settings

# 1. Get fresh UI tree (in case elements moved)
idb ui describe-all --udid booted > logs/ui-tree-2.json

# 2. Find settings-button
SETTINGS_COORDS=$(cat logs/ui-tree-2.json | jq -r '.[] | select(.AXUniqueId == "settings-button") | "\(.frame.x + .frame.width/2) \(.frame.y + .frame.height/2)"')

# 3. Tap settings
idb ui tap --udid booted $(echo $SETTINGS_COORDS | cut -d' ' -f1) $(echo $SETTINGS_COORDS | cut -d' ' -f2)

# 4. Wait for navigation animation
sleep 1

# 5. Screenshot Settings screen
xcrun simctl io booted screenshot logs/settings-screen.png

Python Helper Script (Recommended)

For complex testing, use Python:

#!/usr/bin/env python3
import json
import subprocess
import sys

def get_ui_tree(udid="booted"):
    """Get UI accessibility tree"""
    result = subprocess.run(
        ["idb", "ui", "describe-all", "--udid", udid],
        capture_output=True, text=True
    )
    return json.loads(result.stdout)

def find_element_by_testid(tree, testid):
    """Find element by AXUniqueId (testID)"""
    for element in tree:
        if element.get("AXUniqueId") == testid:
            return element
    return None

def get_tap_coordinates(element):
    """Calculate center coordinates for tapping"""
    frame = element["frame"]
    x = frame["x"] + frame["width"] / 2
    y = frame["y"] + frame["height"] / 2
    return int(x), int(y)

def tap_element(testid, udid="booted"):
    """Find element by testID and tap it"""
    tree = get_ui_tree(udid)
    element = find_element_by_testid(tree, testid)

    if not element:
        print(f"Element with testID '{testid}' not found")
        return False

    if not element.get("enabled", False):
        print(f"Element '{testid}' found but not enabled")
        return False

    x, y = get_tap_coordinates(element)
    print(f"Tapping '{testid}' at ({x}, {y})")

    subprocess.run(["idb", "ui", "tap", "--udid", udid, str(x), str(y)])
    return True

def type_text(text, udid="booted"):
    """Type text into focused field"""
    subprocess.run(["idb", "ui", "text", "--udid", udid, text])

# Usage examples
if __name__ == "__main__":
    # Tap message input
    tap_element("message-input")

    # Type message
    type_text("Hello Claude")

    # Tap send button
    tap_element("send-button")

Save as: scripts/idb-test-helper.py

Use:

python scripts/idb-test-helper.py

Claude Code Mobile testIDs

All interactive elements have testIDs (from codebase review):

ChatScreen:

• chat-header - Header container
• connection-status - Connection indicator
• settings-button - Settings gear icon
• message-list - Messages FlatList
• message-bubble-{id} - Individual message
• message-input - Text input field
• send-button - Send button
• slash-command-menu - Command menu
• slash-command-{name} - Individual command

SettingsScreen:

• settings-header - Header
• back-button - Back navigation
• server-url-input - Server URL field
• project-path-input - Project path field
• auto-scroll-toggle - Auto-scroll switch
• haptic-toggle - Haptic feedback switch
• view-sessions-button - View sessions button

Other Screens:

• filebrowser-header, file-search-input, file-list, file-item-{path}
• codeviewer-header, code-content
• sessions-header, sessions-list, session-item-{id}

Common Mistakes

Mistake	Reality
"Try xc-mcp first"	WRONG if unavailable. Check IDB directly.
"Guess coordinates"	WRONG. Always get UI tree first.
"Tap without verifying enabled"	WRONG. Check enabled: true in tree.
"Use old UI tree"	WRONG. Elements move. Get fresh tree before each tap.
"Tap corner of element"	WRONG. Tap CENTER for reliability.

Red Flags

• "xc-mcp should work" → WRONG if "Not connected". Use IDB.
• "I know where button is" → WRONG. Get UI tree.
• "Coordinates won't change" → WRONG. Re-fetch for accuracy.

Integration with Gate 4A

Complete Gate 4A workflow:

# 1. Screenshot initial state
xcrun simctl io booted screenshot logs/01-initial.png

# 2. Tap message input
idb ui describe-all --udid booted > logs/ui.json
TAP_X=$(cat logs/ui.json | jq '.[] | select(.AXUniqueId == "message-input") | .frame.x + .frame.width/2')
TAP_Y=$(cat logs/ui.json | jq '.[] | select(.AXUniqueId == "message-input") | .frame.y + .frame.height/2')
idb ui tap --udid booted $TAP_X $TAP_Y

# 3. Type message
idb ui text --udid booted "test message"
xcrun simctl io booted screenshot logs/02-typed.png

# 4. Tap send
# (same process with send-button testID)

# 5. Navigate to Settings
# (same process with settings-button testID)

# 6. Verify all 5 screens
# (repeat for each screen's navigation buttons)

Next Steps After Skill

Once skill is created and tested:

1. Use this skill to complete Gate 4A testing
2. Test all 12 Gate 4A criteria autonomously
3. Document results with screenshots
4. Declare Gate 4A PASS/FAIL based on evidence