Debugging macOS App

[georgemp]

Is it possible to use XcodeBuildMCP to debug (lldb) a macOS app? The available tools seem to be debug_attach_sim and debug_attach_device (which are autodetected), but, there doesn't seem to be anything to attach to a macOS app (or the models aren't able to discover it).

Running XcodeBuildMCP via OpenCode. Below is the output from doctor

XcodeBuildMCP Doctor

Generated: 2026-04-25T17:55:11.462Z
Server Version: 2.3.2
Output Mode: Redacted (default)

## System Information
- platform: darwin
- release: 25.4.0
- arch: arm64
- cpus: 10 x Apple M1 Pro
- memory: 16 GB
- hostname: <redacted>
- username: <redacted>
- homedir: /Users/<redacted>
- tmpdir: /var/folders/x6/9kgkzc456yl9_1pqqkpcb3nc0000gn/T

## Node.js Information
- version: v24.14.0
- execPath: /Users/<redacted>/.nvm/versions/node/v24.14.0/bin/node
- pid: 16811
- ppid: 16791
- platform: darwin
- arch: arm64
- cwd: /Users/<redacted>/Work/Programs/Libraries/swift/<redacted>
- argv: /Users/<redacted>/.nvm/versions/node/v24.14.0/bin/node /Users/<redacted>/.npm/_npx/99336612077b7094/node_modules/.bin/xcodebuildmcp-doctor

## Process Tree
- Running under Xcode: ❌ No
- 16811 (ppid 16791): node — node /Users/<redacted>/.npm/_npx/99336612077b7094/node_modules/.bin/xcodebuildmcp-doctor
- 16791 (ppid 14072): npm — exec xcodebu npm exec xcodebuildmcp-doctor
- 14072 (ppid 1616): -zsh — -zsh
- 1616 (ppid 1): tmux — tmux
- 1 (ppid 0): /sbin/launchd — /sbin/launchd

## Xcode Information
- version: Xcode 26.4.1 - Build version 17E202
- path: /Applications/Xcode-26.4.1.app/Contents/Developer
- selectedXcode: /Applications/Xcode-26.4.1.app/Contents/Developer/usr/bin/xcodebuild
- xcrunVersion: xcrun version 72.

## Dependencies
- axe: ✅ v1.5.2
- mise: ❌ Not found

## Environment Variables                                                                                                                                                     23:25 [81/342]
- INCREMENTAL_BUILDS_ENABLED: (not set)
- DEVELOPER_DIR: (not set)
- HOME: /Users/<redacted>
- USER: <redacted>
- TMPDIR: /var/folders/x6/9kgkzc456yl9_1pqqkpcb3nc0000gn/T/
- NODE_ENV: (not set)
- SENTRY_DISABLED: (not set)
- AXE_PATH: (not set)
- XBMCP_LAUNCH_JSON_WAIT_MS: (not set)
- XCODEBUILDMCP_DEBUGGER_BACKEND: (not set)
- XCODEBUILDMCP_UI_DEBUGGER_GUARD_MODE: (not set)
- XCODEBUILDMCP_RUNTIME: cli
- XCODEBUILDMCP_SILENCE_LOGS: true

### PATH

/Users/<redacted>/.npm/_npx/99336612077b7094/node_modules/.bin
/Users/<redacted>/Work/Programs/Libraries/swift/<redacted>/node_modules/.bin
/Users/<redacted>/Work/Programs/Libraries/swift/node_modules/.bin
/Users/<redacted>/Work/Programs/Libraries/node_modules/.bin
/Users/<redacted>/Work/Programs/node_modules/.bin
/Users/<redacted>/Work/node_modules/.bin
/Users/<redacted>/node_modules/.bin
/Users/<redacted>/.bin
/node_modules/.bin
/Users/<redacted>/.nvm/versions/node/v24.14.0/lib/node_modules/npm/node_modules/@npmcli/run-script/lib/node-gyp-bin
/Users/<redacted>/.opencode/bin
/Users/<redacted>/.rbenv/shims
/Users/<redacted>/.nvm/versions/node/v24.14.0/bin
/opt/homebrew/bin
/opt/homebrew/sbin
/usr/local/bin
/System/Cryptexes/App/usr/bin
/usr/bin
/bin
/usr/sbin
/sbin
/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin
/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin
/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin
/opt/pkg/env/active/bin
/opt/pmk/env/global/bin
/Library/Apple/usr/bin
/usr/local/MacGPG2/bin
/Library/TeX/texbin
/Users/<redacted>/.local/bin
/Users/<redacted>/.opencode/bin
/Users/<redacted>/.rbenv/shims
/Users/<redacted>/.nvm/versions/node/v24.14.0/bin
/Users/<redacted>/.sdkman/candidates/sbt/current/bin
/Users/<redacted>/.sdkman/candidates/java/current/bin                                                                                                                        23:25 [30/342]
/Users/<redacted>/.cargo/bin
/Applications/iTerm.app/Contents/Resources/utilities
/Users/<redacted>/.hishtory
/Users/<redacted>/.lmstudio/bin
/Users/<redacted>/.hishtory
/Users/<redacted>/.lmstudio/bin

## Feature Status

### UI Automation (axe)
- Available: ✅ Yes
- UI Automation Supported: ✅ Yes
- Simulator Video Capture Supported (AXe >= 1.1.0): ✅ Yes
- UI-Debugger Guard Mode: error

### Incremental Builds
- Enabled: ❌ No
- xcodemake Binary Available: ❌ No
- Makefile exists (cwd): (not checked: incremental builds disabled)

### Mise Integration
- Running under mise: ❌ No
- Mise available: ❌ No

### Debugger Backend (DAP)
- lldb-dap available: ✅ Yes
- Selected backend: dap

### Manifest Tool Inventory
- Total Unique Tools: 82
- Workflow Count: 16
- coverage: 2 tools
- debugging: 8 tools
- device: 17 tools
- doctor: 1 tools
- logging: 4 tools
- macos: 13 tools
- project-discovery: 5 tools
- project-scaffolding: 2 tools
- session-management: 5 tools
- simulator-management: 8 tools
- simulator: 23 tools
- swift-package: 8 tools
- ui-automation: 11 tools
- utilities: 1 tools
- workflow-discovery: 1 tools
- xcode-ide: 5 tools

### Runtime Tool Registration
- Enabled Workflows: 0
- Registered Tools: 0
- Note: Runtime registry unavailable.

### Xcode IDE Bridge (mcpbridge)
- Workflow enabled: ❌ No
- mcpbridge path: /Applications/Xcode-26.4.1.app/Contents/Developer/usr/bin/mcpbridge
- Xcode running: true
- Connected: ❌ No
- Bridge PID: (none)
- Proxied tools: 0
- Last error: (none)
- Note: Bridge debug tools (status/sync/disconnect) are only registered when debug: true

## Tool Availability Summary
- Build Tools: ✅ Available
- UI Automation Tools: ✅ Available
- Incremental Build Support: ❌ Not available

## Sentry
- Sentry enabled: ✅ Yes

## Troubleshooting Tips
- If UI automation tools are not available, install axe: `brew tap cameroncooke/axe && brew install axe`
- If incremental build support is not available, install xcodemake (https://github.com/cameroncooke/xcodemake) and ensure it is executable and available in your PATH
- To enable xcodemake, set environment variable: `export INCREMENTAL_BUILDS_ENABLED=1`
- For mise integration, follow instructions in the README.md file

Doctor run complete. Please include this output when reporting issues.

[cookesan]

From the current tool surface, I don't see a macOS LLDB attach tool. The macOS workflow exposes build/run/test for macOS apps; the debug attach tools I can find are simulator/device-oriented (debug_attach_sim, plus the device attach path in the discovery inventory). So your reading of the available tools looks correct: macOS app debugging is not currently exposed as a separate attach workflow.

One thing to double-check is workflow enablement, because the project gates some workflows and only simulator tools are enabled by default. But even with all workflows enabled, I would expect build_run_macos for launching and then an external LLDB/Xcode attach as the current workaround.

It may be worth turning this into a feature request for a debug_attach_macos-style tool, because the gap is distinct from simply not discovering the existing simulator/device attach tools.