iOS Debugger Agent

Use the repository-configured xcodebuildmcp tools instead of requiring a globally installed Codex plugin. Prefer MCP tools over raw xcodebuild, xcrun, or simctl when the client exposes them.

Confirm availability

This workflow requires macOS 14.5 or newer, Xcode 16 or newer, and Node.js 18 or newer. The repository pins XcodeBuildMCP in both .mcp.json for Claude Code and .codex/config.toml for Codex. Project MCP servers may require one-time trust or approval followed by a new session.

If the tools are missing:

1. Confirm the repository is trusted and its project MCP server was approved.
2. Restart or recreate the agent session after approving configuration.
3. Run npx --yes xcodebuildmcp@2.6.2 doctor when the server starts but simulator or UI-automation tools are unavailable. Follow its actionable Xcode or AXe setup guidance.
4. Fall back to the pinned XcodeBuildMCP CLI or native Apple CLIs only when the current agent client cannot expose project MCP tools.

Do not ask contributors to install the OpenAI build-ios-apps plugin globally.

Establish one simulator context

1. Call session_show_defaults before discovery, build, launch, or UI work.
2. Call list_sims and select one explicit simulator UDID. Prefer a simulator that is already booted; boot an installed simulator when verification requires it, but do not create or download runtimes without user authorization.
3. Call session_set_defaults with the project or workspace, scheme, Debug configuration, simulator ID, and bundle identifier when known.
4. Keep every subsequent build, launch, screenshot, log capture, and UI action pinned to that same UDID.

Avoid generic Mac window automation for switching among Simulator windows. Explicit device identity is more reliable.

Choose build or launch

For T3 Code Mobile, run node scripts/mobile-native-client.ts ensure ios <simulator-udid> from the checkout on the simulator host first. It checks the local Expo native fingerprint against the installed client and builds/installs when stale, missing, or unknown. Then launch with the intended Metro bundle. Authorized verification includes native builds and installs; do not stop because the existing client is old. Use check instead of ensure only when the user explicitly prohibits rebuilding or requests a read-only check.

• Use build_run_sim when native source, native dependencies, entitlements, or project configuration changed.
• Use test_sim for the smallest relevant native test target or test cases; do not run an entire workspace test matrix routinely.
• Use launch_app_sim when a compatible app is already installed and no native rebuild is needed.
• To reuse an existing build artifact, use get_sim_app_path or get_app_bundle_id, install it with install_app_sim when necessary, and then launch it.
• Do not run a build-only action immediately before build_run_sim unless the task requires both artifacts.

After launch, call snapshot_ui or screenshot before interacting. An open Simulator window alone is not evidence that the intended app launched.

Drive the UI semantically

1. Call snapshot_ui to obtain the current accessibility hierarchy and element references.
2. Use only current elementRef values whose snapshot entries list the intended action. XcodeBuildMCP 2.6.2 does not accept coordinates for tap; when the app exposes no actionable reference, prefer a registered deep link or another app-supported route and otherwise report the accessibility blocker.
3. Refresh with snapshot_ui after navigation or layout changes. Element references are snapshot-specific.
4. Use wait_for_ui for asynchronous transitions when available rather than fixed sleeps.
5. Capture a final screenshot for the state that proves the affected flow.

Use gesture or scoped swipe actions when needed. If a gesture is unreliable, return to a known route or relaunch rather than switching to generic desktop automation.

Capture logs and debug

• Use start_sim_log_cap and stop_sim_log_cap with the exact bundle identifier for focused runtime logs.
• Use debugger tools only when the task requires runtime diagnosis; attach to the selected simulator and app rather than an ambiguous process.
• Summarize relevant errors instead of returning unbounded logs.

Clean up

Stop only log captures, debugger sessions, apps, or simulators started for the current test. Leave pre-existing simulators and unrelated sessions alone.

Upstream

Adapted from OpenAI's build-ios-apps plugin version 0.1.2 (ios-debugger-agent, MIT) and aligned with XcodeBuildMCP 2.6.2 tool names.