mcpbridge-wrapper 0.4.0

Python wrapper for xcrun mcpbridge that adds structuredContent to MCP responses

XcodeMCPWrapper - mcpbridge-wrapper

A Python wrapper that makes Xcode 26.3's MCP bridge compatible with Cursor and other strict MCP-spec-compliant clients.

The Problem

Xcode's mcpbridge returns tool responses in the content field but omits the required structuredContent field when a tool declares an outputSchema. According to the MCP specification, when outputSchema is declared, responses must include structuredContent.

• ✅ Claude Code and Codex CLI work (they have special handling for Apple's responses)
• ❌ Cursor strictly follows the spec and rejects non-compliant responses

The Solution

mcpbridge-wrapper intercepts responses from xcrun mcpbridge and copies the data from content into structuredContent, making Xcode's MCP tools fully compatible with all MCP clients.

┌─────────────┐    MCP Protocol    ┌──────────────────┐   MCP Protocol   ┌────────────┐    XPC    ┌─────────┐
│   Cursor    │ ◄────────────────► │ mcpbridge-wrapper│ ◄──────────────► │ mcpbridge  │ ◄───────► │  Xcode  │
│ (MCP Client)│                    │  (This Project)  │                  │  (Bridge)  │           │  (IDE)  │
└─────────────┘                    └──────────────────┘                  └────────────┘           └─────────┘

Quick Start

Prerequisites

• macOS with Xcode 26.3+
• Python 3.9+
• Xcode Tools MCP Server enabled (see below)

⚠️ Important: You MUST enable Xcode Tools MCP in Xcode settings:

1. Open Xcode > Settings (⌘,)
2. Select Intelligence in the sidebar
3. Under Model Context Protocol, toggle Xcode Tools ON

If you see "Found 0 tools" in your MCP client logs, this setting is not enabled.

Cursor Quick Setup

If you use Cursor, no installation is needed — just add this to ~/.cursor/mcp.json:

Broker mode (Recommended):

{
  "mcpServers": {
    "xcode-tools": {
      "command": "uvx",
      "args": ["--from", "mcpbridge-wrapper", "mcpbridge-wrapper", "--broker"]
    }
  }
}

With Web UI dashboard (optional — adds real-time monitoring at http://localhost:8080):

{
  "mcpServers": {
    "xcode-tools": {
      "command": "uvx",
      "args": [
        "--from",
        "mcpbridge-wrapper[webui]",
        "mcpbridge-wrapper",
        "--broker",
        "--web-ui",
        "--web-ui-config",
        "/Users/YOUR_USERNAME/.mcpbridge_wrapper/webui.json"
      ]
    }
  }
}

Direct mode (Alternative):

{
  "mcpServers": {
    "xcode-tools": {
      "command": "uvx",
      "args": ["--from", "mcpbridge-wrapper", "mcpbridge-wrapper"]
    }
  }
}

If you upgrade and want to confirm the currently running dashboard process version:

PORT=8080
PID=$(lsof -tiTCP:$PORT -sTCP:LISTEN | head -n1)
PY=$(ps -p "$PID" -o command= | awk '{print $1}')
"$PY" -c 'import importlib.metadata as m; print(m.version("mcpbridge-wrapper"))'

If needed, do a one-time refresh start:

uvx --refresh --from 'mcpbridge-wrapper[webui]' mcpbridge-wrapper --web-ui --web-ui-port 8080

Restart Cursor and you're done. For other clients or installation methods, read on.

Broker Mode

Broker mode lets multiple short-lived MCP client sessions share one persistent upstream bridge session.

• Why this mode exists: Apple documents a Coding Intelligence known issue in Xcode 26.4 where external development tools may trigger repeated "Allow Connection?" dialogs during normal usage (170721057). Reusing one long-lived upstream session via broker mode can reduce reconnect churn that surfaces this prompt pattern. See Apple's official Xcode 26.4 release notes.
• Use --broker to auto-detect — connect if daemon is alive, spawn otherwise (recommended).
• Add --web-ui (plus optional --web-ui-config) when you want the spawned or daemon host to own one shared dashboard endpoint.

Quick migration examples:

# Claude Code
claude mcp add --transport stdio xcode -- uvx --from mcpbridge-wrapper mcpbridge-wrapper --broker

# Codex CLI
codex mcp add xcode -- uvx --from mcpbridge-wrapper mcpbridge-wrapper --broker

For full start/stop/status commands, Cursor JSON snippets, troubleshooting, and rollback to direct mode, see Broker Mode Guide.

Multi-Agent Guidance

When you run multiple MCP client processes at the same time:

• Unified single-config pattern: configure each client with --broker --web-ui --web-ui-config <shared-path>.
• Runtime expectation: the first client that must spawn the broker starts the broker host and dashboard; later clients reuse the same broker and dashboard endpoint.
• Ownership rule: only one process can bind a given Web UI host:port (for example 127.0.0.1:8080).
• Connection behavior: when a broker is already running, --broker reuses it and does not retrofit dashboard settings onto that existing host.
• Fallback behavior: if dashboard bind fails (port already in use), broker MCP transport continues and only dashboard startup is skipped.

See Web UI Setup Guide and Troubleshooting.

Python Environment Setup (Development)

If you plan to run make install, pytest, or other development commands, create and activate a virtual environment first. This avoids Homebrew Python's externally-managed-environment (PEP 668) error.

cd XcodeMCPWrapper
python3 -m venv .venv
source .venv/bin/activate
python3 -m pip install --upgrade pip
make install

Quick checks:

which python3
which pip

Both should point to .venv/bin/... while the environment is active.

Installation

Option 1: Using uvx (Recommended - Easiest)

The fastest way to install is using uvx (requires uv to be installed):

# No manual installation needed - uvx will automatically download and run
uvx --from mcpbridge-wrapper mcpbridge-wrapper

Or add to your MCP client configuration directly (see configuration sections below).

Option 2: Via MCP Registry

If your MCP client supports the MCP Registry:

Server name: io.github.SoundBlaster/xcode-mcpbridge-wrapper

# Using mcp-publisher CLI
mcp-publisher install io.github.SoundBlaster/xcode-mcpbridge-wrapper

Option 3: Using pip

python3 -m pip install mcpbridge-wrapper

Then use mcpbridge-wrapper or xcodemcpwrapper command.

Option 4: Manual Installation (via install script)

git clone https://github.com/SoundBlaster/XcodeMCPWrapper.git
cd XcodeMCPWrapper
./scripts/install.sh

The install script creates a virtual environment, installs the package, and places a wrapper at ~/bin/xcodemcpwrapper.

If you plan to use --web-ui MCP args, install Web UI extras explicitly:

./scripts/install.sh --webui

Add the following to your ~/.bashrc or ~/.zshrc:

export PATH="$HOME/bin:$PATH"

Then reload:

source ~/.zshrc
# or
. ~/.zshrc

Option 5: Local Development (venv)

For development or if you want to run directly from the cloned repository:

git clone https://github.com/SoundBlaster/XcodeMCPWrapper.git
cd XcodeMCPWrapper
python3 -m venv .venv
source .venv/bin/activate
make install          # or: make install-webui (for Web UI support)

The entry point is .venv/bin/mcpbridge-wrapper. Use the full absolute path when configuring MCP clients (see configuration sections below).

Uninstallation

To remove xcodemcpwrapper from your system:

./scripts/uninstall.sh

Options:

• --dry-run or -n: Show what would be removed without removing
• --yes or -y: Skip confirmation prompt

Configuration

Cursor

Broker setup examples are listed first.

Using uvx in broker mode (Recommended):

{
  "mcpServers": {
    "xcode-tools": {
      "command": "uvx",
      "args": ["--from", "mcpbridge-wrapper", "mcpbridge-wrapper", "--broker"]
    }
  }
}

Using uvx in broker mode with Web UI (Optional):

{
  "mcpServers": {
    "xcode-tools": {
      "command": "uvx",
      "args": [
        "--from",
        "mcpbridge-wrapper[webui]",
        "mcpbridge-wrapper",
        "--broker",
        "--web-ui",
        "--web-ui-config",
        "/Users/YOUR_USERNAME/.mcpbridge_wrapper/webui.json"
      ]
    }
  }
}

Using uvx in direct mode:

{
  "mcpServers": {
    "xcode-tools": {
      "command": "uvx",
      "args": ["--from", "mcpbridge-wrapper", "mcpbridge-wrapper"]
    }
  }
}

Using uvx in direct mode with Web UI (Optional):

{
  "mcpServers": {
    "xcode-tools": {
      "command": "uvx",
      "args": [
        "--from",
        "mcpbridge-wrapper[webui]",
        "mcpbridge-wrapper",
        "--web-ui",
        "--web-ui-port",
        "8080"
      ]
    }
  }
}

Using manual installation (Direct mode):

{
  "mcpServers": {
    "xcode-tools": {
      "command": "/Users/YOUR_USERNAME/bin/xcodemcpwrapper",
      "args": []
    }
  }
}

Using manual installation with Web UI (Direct mode, optional):

Requires installing with ./scripts/install.sh --webui (or equivalent .[webui] dependencies).

{
  "mcpServers": {
    "xcode-tools": {
      "command": "/Users/YOUR_USERNAME/bin/xcodemcpwrapper",
      "args": ["--web-ui", "--web-ui-port", "8080"]
    }
  }
}

Using local development (venv, direct mode):

{
  "mcpServers": {
    "xcode-tools": {
      "command": "/path/to/XcodeMCPWrapper/.venv/bin/mcpbridge-wrapper"
    }
  }
}

Using local development with Web UI (Direct mode, optional):

{
  "mcpServers": {
    "xcode-tools": {
      "command": "/path/to/XcodeMCPWrapper/.venv/bin/mcpbridge-wrapper",
      "args": ["--web-ui", "--web-ui-port", "8080"]
    }
  }
}

Claude Code

Broker setup examples are listed first.

Using uvx in broker mode (Recommended):

claude mcp add --transport stdio xcode -- uvx --from mcpbridge-wrapper mcpbridge-wrapper --broker

Using uvx in broker mode with Web UI (Optional):

claude mcp add --transport stdio xcode -- uvx --from 'mcpbridge-wrapper[webui]' mcpbridge-wrapper --broker --web-ui --web-ui-config "$HOME/.mcpbridge_wrapper/webui.json"

Using uvx in direct mode:

claude mcp add --transport stdio xcode -- uvx --from mcpbridge-wrapper mcpbridge-wrapper

Using uvx in direct mode with Web UI (Optional):

claude mcp add --transport stdio xcode -- uvx --from 'mcpbridge-wrapper[webui]' mcpbridge-wrapper --web-ui --web-ui-port 8080

Using manual installation (Direct mode):

claude mcp add --transport stdio xcode -- ~/bin/xcodemcpwrapper

Using manual installation with Web UI (Direct mode, optional): Requires installing with ./scripts/install.sh --webui (or equivalent .[webui] dependencies).

claude mcp add --transport stdio xcode -- ~/bin/xcodemcpwrapper --web-ui --web-ui-port 8080

Using local development (venv, direct mode):

claude mcp add --transport stdio xcode -- /path/to/XcodeMCPWrapper/.venv/bin/mcpbridge-wrapper

Using local development with Web UI (Direct mode, optional):

claude mcp add --transport stdio xcode -- /path/to/XcodeMCPWrapper/.venv/bin/mcpbridge-wrapper --web-ui --web-ui-port 8080

Codex CLI

Broker setup examples are listed first.

Using uvx in broker mode (Recommended):

codex mcp add xcode -- uvx --from mcpbridge-wrapper mcpbridge-wrapper --broker

Using uvx in broker mode with Web UI (Optional):

codex mcp add xcode -- uvx --from 'mcpbridge-wrapper[webui]' mcpbridge-wrapper --broker --web-ui --web-ui-config "$HOME/.mcpbridge_wrapper/webui.json"

Using uvx in direct mode:

codex mcp add xcode -- uvx --from mcpbridge-wrapper mcpbridge-wrapper

Using uvx in direct mode with Web UI (Optional):

codex mcp add xcode -- uvx --from 'mcpbridge-wrapper[webui]' mcpbridge-wrapper --web-ui --web-ui-port 8080

Using manual installation (Direct mode):

codex mcp add xcode -- ~/bin/xcodemcpwrapper

Using manual installation with Web UI (Direct mode, optional): Requires installing with ./scripts/install.sh --webui (or equivalent .[webui] dependencies).

codex mcp add xcode -- ~/bin/xcodemcpwrapper --web-ui --web-ui-port 8080

Using local development (venv, direct mode):

codex mcp add xcode -- /path/to/XcodeMCPWrapper/.venv/bin/mcpbridge-wrapper

Using local development with Web UI (Direct mode, optional):

codex mcp add xcode -- /path/to/XcodeMCPWrapper/.venv/bin/mcpbridge-wrapper --web-ui --web-ui-port 8080

Zed Agent

Using uvx (Recommended):

Edit ~/.zed/settings.json:

{
  "xcode-tools": {
    "command": "uvx",
    "args": ["--from", "mcpbridge-wrapper", "mcpbridge-wrapper"],
    "env": {}
  }
}

Using uvx with Web UI (Optional):

{
  "xcode-tools": {
    "command": "uvx",
    "args": [
      "--from",
      "mcpbridge-wrapper[webui]",
      "mcpbridge-wrapper",
      "--web-ui",
      "--web-ui-port",
      "8080"
    ],
    "env": {}
  }
}

Using manual installation:

{
  "xcode-tools": {
    "command": "/Users/YOUR_USERNAME/bin/xcodemcpwrapper",
    "args": [],
    "env": {}
  }
}

Using manual installation with Web UI (Optional): Requires installing with ./scripts/install.sh --webui (or equivalent .[webui] dependencies).

{
  "xcode-tools": {
    "command": "/Users/YOUR_USERNAME/bin/xcodemcpwrapper",
    "args": ["--web-ui", "--web-ui-port", "8080"],
    "env": {}
  }
}

Using local development (venv, direct mode):

{
  "xcode-tools": {
    "command": "/path/to/XcodeMCPWrapper/.venv/bin/mcpbridge-wrapper",
    "args": [],
    "env": {}
  }
}

Using local development with Web UI (Direct mode, optional):

{
  "xcode-tools": {
    "command": "/path/to/XcodeMCPWrapper/.venv/bin/mcpbridge-wrapper",
    "args": ["--web-ui", "--web-ui-port", "8080"],
    "env": {}
  }
}

Kimi CLI

Using uvx (Recommended):

Edit ~/.kimi/mcp.json:

{
  "xcode-tools": {
    "command": "uvx",
    "args": ["--from", "mcpbridge-wrapper", "mcpbridge-wrapper"],
    "env": {}
  }
}

Using manual installation:

{
  "xcode-tools": {
    "command": "/Users/YOUR_USERNAME/bin/xcodemcpwrapper",
    "args": [],
    "env": {}
  }
}

Usage

Once configured, ask your AI assistant to use Xcode tools:

"Build my project"
"Run the tests"
"Find all Swift files in the project"
"Show me the build errors"

Web UI Dashboard (Optional)

The wrapper includes an optional Web UI dashboard for real-time monitoring and audit logging:

# Start with Web UI
make webui

# Or directly
python -m mcpbridge_wrapper --web-ui --web-ui-port 8080

Features:

• Real-time metrics: RPS, latency percentiles (p50, p95, p99), error rates
• Tool usage analytics: Visual charts of most frequently used tools
• Audit logging: Persistent log of all MCP tool calls with export (JSON/CSV)
• Request inspector: Live log stream with filtering

Open http://localhost:8080 in your browser to view the dashboard.

Important for multi-agent setups:

• The dashboard is hosted by one wrapper process, not by Xcode or mcpbridge.
• A single host:port can have only one listener; additional processes on the same port skip dashboard startup and continue MCP traffic.

See Web UI Setup Guide for detailed configuration.

Known Issues

• Broker cold-start — Xcode approval timing race (0 tools with green dot): When the broker daemon starts a new xcrun mcpbridge process (on first launch or after a daemon restart), Xcode shows a per-process "Allow Connection?" dialog. If your MCP client sends tools/list before Xcode grants approval, it receives an empty list and caches it permanently — showing 0 tools with a green connected indicator and no error message. Each unique binary path (direct wrapper vs broker daemon) triggers a separate dialog. After approval the permission persists — no re-approval is needed on subsequent sessions. Workaround: watch for the Xcode dialog immediately after enabling broker mode; after clicking Allow, reload the MCP connection in your client (disable → re-enable in settings). See Troubleshooting: 0 tools after first broker connection for client-specific recovery steps and the diagnostic command.
• BUG-T5 → FU-P13-T7 (P0): Empty-content tool results can still violate strict structuredContent expectations in strict MCP clients.
• BUG-T6 → FU-P13-T8 (P0): Web UI port collisions can happen when multiple MCP sessions start with the same --web-ui-port (for example 8080), producing address already in use.
• BUG-T7 → FU-P13-T9 (P0): resources/list and resources/templates/list probing may return non-standard error shapes in some client paths.

Disclaimer (Codex App)

mcpbridge-wrapper normalizes Xcode MCP responses, but it does not control Codex App internals. Codex App transport/session behavior may change independently from Codex CLI and from this wrapper. If App and CLI differ, treat that as client-specific behavior first and verify with exact versions, config, and logs.

Documentation

• Installation Guide
• Broker Mode Guide - Configuration, migration, rollback, and operations
• Web UI Dashboard - Real-time monitoring and audit logging
• Cursor Setup
• Claude Code Setup
• Codex CLI Setup
• Troubleshooting
• Tools Reference
• Architecture
• Contributing - Development guide and quality gates

Development

See CONTRIBUTING.md for development setup and contribution guidelines.

Quick quality gate check:

make test      # Run tests with coverage
make lint      # Run ruff linter
make typecheck # Run mypy type checker

Or run all gates:

make test && make lint && make typecheck

Performance

• Overhead: <0.01ms per transformation
• Memory: <10MB footprint
• Coverage: 90.91% test coverage

License

MIT License - see LICENSE for details.

Acknowledgments

• Apple's Xcode team for the MCP bridge functionality
• The MCP protocol specification
• The Cursor, Claude, and Codex teams for AI-powered development tools