axiom-xcode-mcp-setup
Xcode MCP Setup
Prerequisites
- Xcode 26.3+ with MCP support
- macOS with Xcode installed and running
- At least one project/workspace open in Xcode
Step 1: Enable MCP in Xcode
- Open Xcode Settings (Cmd+,)
- Go to Intelligence tab
- Check Enable Model Context Protocol
- Ensure Xcode Tools toggle is ON
Without this toggle, xcrun mcpbridge connects but returns no tools.
Step 2: Connect Your MCP Client
Claude Code
claude mcp add --transport stdio xcode -- xcrun mcpbridge
Verify: claude mcp list should show xcode server.
Codex
codex mcp add xcode -- xcrun mcpbridge
Cursor
Create or edit .cursor/mcp.json in your project root:
{
"mcpServers": {
"xcode": {
"command": "xcrun",
"args": ["mcpbridge"]
}
}
}
Cursor-specific note: Cursor is a strict MCP client. Xcode's mcpbridge omits structuredContent when tools declare outputSchema, which violates the MCP spec. If Cursor rejects responses, use XcodeMCPWrapper as a proxy:
{
"mcpServers": {
"xcode": {
"command": "/path/to/XcodeMCPWrapper",
"args": []
}
}
}
VS Code + GitHub Copilot
Create or edit .vscode/mcp.json:
{
"servers": {
"xcode": {
"type": "stdio",
"command": "xcrun",
"args": ["mcpbridge"]
}
}
}
Gemini CLI
gemini mcp add xcode -- xcrun mcpbridge
Step 3: Verify Connection
After configuration, call XcodeListWindows (no parameters). You should see:
tabIdentifier: <uuid>, workspacePath: /path/to/YourProject.xcodeproj
If you see an empty list, ensure a project is open in Xcode.
Permission Dialog
When an MCP client first connects, Xcode shows a permission dialog:
- Identifies the connecting process by PID
- Asks to allow MCP tool access
- Must be approved in Xcode's UI (not terminal)
PID-based approval: Permission is granted per-process. If the client restarts (new PID), you'll see the dialog again. This is expected behavior.
Multi-Xcode Targeting
When multiple Xcode instances are running:
Auto-Detection (default)
mcpbridge auto-selects using this fallback:
- If exactly one Xcode process is running → uses that
- If multiple → uses the one matching
xcode-select - If none → exits with error
Manual PID Selection
Set MCP_XCODE_PID to target a specific instance:
# Find Xcode PIDs
pgrep -x Xcode
# Claude Code with specific PID
claude mcp add --transport stdio xcode -- env MCP_XCODE_PID=12345 xcrun mcpbridge
Session ID (optional)
MCP_XCODE_SESSION_ID provides a stable UUID for tool sessions, useful when tracking interactions across reconnections.
Troubleshooting
digraph troubleshoot {
rankdir=TB;
"Connection failed?" [shape=diamond];
"tools/list empty?" [shape=diamond];
"Wrong project?" [shape=diamond];
"Repeated permission prompts?" [shape=diamond];
"Client rejects responses?" [shape=diamond];
"Check Xcode running + toggle on" [shape=box];
"Open a project in Xcode" [shape=box];
"Use MCP_XCODE_PID or check tab targeting" [shape=box];
"Expected: PID changes on restart" [shape=box];
"Use XcodeMCPWrapper proxy" [shape=box];
"Connection failed?" -> "Check Xcode running + toggle on" [label="refused/timeout"];
"Connection failed?" -> "tools/list empty?" [label="connects OK"];
"tools/list empty?" -> "Open a project in Xcode" [label="no tools"];
"tools/list empty?" -> "Wrong project?" [label="tools listed"];
"Wrong project?" -> "Use MCP_XCODE_PID or check tab targeting" [label="yes"];
"Wrong project?" -> "Repeated permission prompts?" [label="no"];
"Repeated permission prompts?" -> "Expected: PID changes on restart" [label="yes"];
"Repeated permission prompts?" -> "Client rejects responses?" [label="no"];
"Client rejects responses?" -> "Use XcodeMCPWrapper proxy" [label="strict client (Cursor)"];
}
Common Issues
| Symptom | Cause | Fix |
|---|---|---|
| "Connection refused" | Xcode not running or MCP toggle off | Launch Xcode, enable MCP in Settings > Intelligence |
| tools/list returns empty | No project open, or permission not granted | Open a project, check for permission dialog in Xcode |
| Tools target wrong project | Multiple Xcode windows, wrong tab | Call XcodeListWindows, use correct tabIdentifier |
| Repeated permission prompts | Client restarted (new PID) | Expected behavior — approve each time |
| Cursor/strict client errors | Missing structuredContent in response |
Use XcodeMCPWrapper as proxy |
| "No such command: mcpbridge" | Xcode < 26.3 | Update to Xcode 26.3+ |
| Slow/hanging tool calls | Large project indexing | Wait for Xcode indexing to complete |
Xcode Built-in Assistant Config
Xcode also supports MCP servers for its built-in assistants. Config files live at:
~/Library/Developer/Xcode/CodingAssistant/codex
~/Library/Developer/Xcode/CodingAssistant/ClaudeAgentConfig
These are for configuring Xcode's internal assistant, separate from external MCP client setup.
Resources
Docs: /xcode/mcp-server
Skills: axiom-xcode-mcp-tools, axiom-xcode-mcp-ref