diff --git a/scripts/diagnose_macos_keyboard_event_path.py b/scripts/diagnose_macos_keyboard_event_path.py
new file mode 100644
index 0000000..8ae5faf
--- /dev/null
+++ b/scripts/diagnose_macos_keyboard_event_path.py
@@ -0,0 +1,309 @@
+#!/usr/bin/env python3
+"""Discriminate PID-targeted key delivery across AppKit and WKWebView on a real Mac.
+
+This is a diagnostic-only probe. It does not launch ClosedRoom or read meeting data.
+It creates a minimal NSWindow + WKWebView, installs the same app-local NSEvent
+monitor shape used by ClosedRoom, sends Cmd-K and Escape through the repository's
+stable PID-targeted Accessibility helper, and records only bounded technical state.
+"""
+from __future__ import annotations
+
+import argparse
+import json
+import os
+import subprocess
+import sys
+import threading
+import time
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any
+
+import objc
+from AppKit import (
+    NSApplication,
+    NSApplicationActivationPolicyRegular,
+    NSBackingStoreBuffered,
+    NSEvent,
+    NSEventMaskKeyDown,
+    NSEventModifierFlagCommand,
+    NSViewHeightSizable,
+    NSViewWidthSizable,
+    NSWindow,
+    NSWindowStyleMaskClosable,
+    NSWindowStyleMaskResizable,
+    NSWindowStyleMaskTitled,
+)
+from PyObjCTools import AppHelper
+
+SCRIPT_DIR = Path(__file__).resolve().parent
+if str(SCRIPT_DIR) not in sys.path:
+    sys.path.insert(0, str(SCRIPT_DIR))
+
+from macos_ui_driver import (  # noqa: E402
+    AccessibilityPermissionRequired,
+    UIAutomationError,
+    default_driver,
+)
+
+try:
+    objc.loadBundle(
+        "WebKit",
+        globals(),
+        bundle_path="/System/Library/Frameworks/WebKit.framework",
+    )
+    WKWebView = objc.lookUpClass("WKWebView")
+except Exception as exc:  # pragma: no cover - target-Mac only
+    raise SystemExit(f"webkit_unavailable:{type(exc).__name__}") from exc
+
+DRIVER = default_driver()
+
+
+def parse_args() -> argparse.Namespace:
+    parser = argparse.ArgumentParser(
+        description="Probe PID-targeted CGEvent -> NSEvent monitor -> WKWebView DOM delivery"
+    )
+    parser.add_argument("--root", default=".")
+    parser.add_argument("--output")
+    parser.add_argument("--settle-seconds", type=float, default=1.5)
+    return parser.parse_args()
+
+
+def git_revision(root: Path) -> str:
+    completed = subprocess.run(
+        ["git", "rev-parse", "HEAD"],
+        cwd=root,
+        capture_output=True,
+        text=True,
+        check=True,
+        timeout=5,
+    )
+    return completed.stdout.strip()
+
+
+def bounded_completion_result(result: Any) -> dict[str, Any]:
+    if not isinstance(result, dict):
+        return {"default_prevented": None}
+    return {"default_prevented": bool(result.get("defaultPrevented"))}
+
+
+def classify(trace: list[dict[str, Any]], dom: dict[str, Any]) -> str:
+    cmd_monitor = any(
+        item.get("event") == "monitor_received" and item.get("key_code") == 40
+        for item in trace
+    )
+    cmd_match = any(item.get("event") == "cmd_k_matched" for item in trace)
+    cmd_bridge = any(
+        item.get("event") == "bridge_completion"
+        and item.get("key") == "KeyK"
+        and item.get("success") is True
+        for item in trace
+    )
+    cmd_dom = int(dom.get("cmd_k_count") or 0) > 0
+
+    if not cmd_monitor:
+        return "pid_targeted_cmd_k_did_not_reach_local_monitor"
+    if not cmd_match:
+        return "cmd_k_reached_monitor_but_did_not_match"
+    if not cmd_bridge:
+        return "cmd_k_matched_but_webview_bridge_did_not_complete"
+    if not cmd_dom:
+        return "cmd_k_bridge_completed_but_dom_listener_not_reached"
+    return "minimal_keyboard_path_succeeded"
+
+
+def main() -> int:
+    args = parse_args()
+    root = Path(args.root).resolve()
+    revision = git_revision(root)
+    output = (
+        Path(args.output).expanduser().resolve()
+        if args.output
+        else root
+        / "dist"
+        / "evidence"
+        / "local-real-environment"
+        / revision[:12]
+        / "macos-keyboard-event-path.json"
+    )
+    output.parent.mkdir(parents=True, exist_ok=True)
+
+    trace: list[dict[str, Any]] = []
+    report: dict[str, Any] = {
+        "schema_version": 1,
+        "diagnostic": "macos_keyboard_event_path",
+        "status": "error",
+        "classification": None,
+        "execution_environment": "target-macos-real",
+        "qualification_scope": "diagnostic_only",
+        "source_revision": revision,
+        "pid": os.getpid(),
+        "privacy_boundary": (
+            "Probe contains only key codes, modifier booleans, bounded bridge completion state, "
+            "window-key state and synthetic DOM counters. It does not launch ClosedRoom, inspect "
+            "meeting data, persist labels/titles/input values, or establish release qualification."
+        ),
+        "started_at": datetime.now(timezone.utc).isoformat(),
+        "trace": trace,
+        "dom": {},
+        "errors": [],
+    }
+
+    app = NSApplication.sharedApplication()
+    app.setActivationPolicy_(NSApplicationActivationPolicyRegular)
+    style = NSWindowStyleMaskTitled | NSWindowStyleMaskClosable | NSWindowStyleMaskResizable
+    window = NSWindow.alloc().initWithContentRect_styleMask_backing_defer_(
+        ((160, 160), (720, 480)), style, NSBackingStoreBuffered, False
+    )
+    window.setTitle_("ClosedRoom Keyboard Path Diagnostic")
+
+    webview = WKWebView.alloc().initWithFrame_(window.contentView().frame())
+    webview.setAutoresizingMask_(NSViewWidthSizable | NSViewHeightSizable)
+    window.setContentView_(webview)
+
+    html = """
+<!doctype html>
+<html>
+<head><meta charset="utf-8"><title>Keyboard Path Diagnostic</title></head>
+<body tabindex="0">
+<script>
+window.__closedroomProbe = {cmdKCount: 0, escapeCount: 0};
+window.addEventListener('keydown', (event) => {
+  if ((event.metaKey || event.ctrlKey) && event.key.toLowerCase() === 'k') {
+    event.preventDefault();
+    window.__closedroomProbe.cmdKCount += 1;
+  }
+  if (event.key === 'Escape') {
+    event.preventDefault();
+    window.__closedroomProbe.escapeCount += 1;
+  }
+});
+document.body.focus();
+</script>
+</body>
+</html>
+"""
+    webview.loadHTMLString_baseURL_(html, None)
+
+    def bridge(*, key: str, code: str, meta_key: bool) -> None:
+        trace.append({"event": "bridge_requested", "key": code})
+        meta_value = "true" if meta_key else "false"
+        js = (
+            "(() => {"
+            "const target = document.activeElement || document.body || document;"
+            "const event = new KeyboardEvent('keydown', {"
+            f"key: {key!r}, code: {code!r}, metaKey: {meta_value}, "
+            "bubbles: true, cancelable: true"
+            "});"
+            "target.dispatchEvent(event);"
+            "return {defaultPrevented: event.defaultPrevented};"
+            "})();"
+        )
+
+        def completed(result: Any, error: Any) -> None:
+            item: dict[str, Any] = {
+                "event": "bridge_completion",
+                "key": code,
+                "success": error is None,
+            }
+            item.update(bounded_completion_result(result))
+            if error is not None:
+                item["error_type"] = type(error).__name__
+            trace.append(item)
+
+        webview.evaluateJavaScript_completionHandler_(js, completed)
+
+    def local_key_monitor(event: Any) -> Any:
+        key_code = int(event.keyCode())
+        modifiers = int(event.modifierFlags())
+        command_pressed = bool(modifiers & NSEventModifierFlagCommand)
+        semantic_k = str(event.charactersIgnoringModifiers() or "").lower() == "k"
+        trace.append(
+            {
+                "event": "monitor_received",
+                "key_code": key_code,
+                "command_pressed": command_pressed,
+                "semantic_k": semantic_k,
+                "window_is_key": bool(window.isKeyWindow()),
+            }
+        )
+        if command_pressed and (key_code == 40 or semantic_k):
+            trace.append({"event": "cmd_k_matched"})
+            bridge(key="k", code="KeyK", meta_key=True)
+        elif key_code == 53:
+            trace.append({"event": "escape_matched"})
+            bridge(key="Escape", code="Escape", meta_key=False)
+        return event
+
+    monitor = NSEvent.addLocalMonitorForEventsMatchingMask_handler_(
+        NSEventMaskKeyDown,
+        local_key_monitor,
+    )
+
+    window.makeKeyAndOrderFront_(None)
+    app.activateIgnoringOtherApps_(True)
+
+    def finalize_on_main() -> None:
+        js = (
+            "JSON.stringify({"
+            "cmd_k_count: window.__closedroomProbe ? window.__closedroomProbe.cmdKCount : 0,"
+            "escape_count: window.__closedroomProbe ? window.__closedroomProbe.escapeCount : 0"
+            "})"
+        )
+
+        def completed(result: Any, error: Any) -> None:
+            if error is not None:
+                report["errors"].append(f"dom_snapshot:{type(error).__name__}")
+            else:
+                try:
+                    payload = json.loads(str(result or "{}"))
+                except json.JSONDecodeError:
+                    payload = {}
+                report["dom"] = {
+                    "cmd_k_count": int(payload.get("cmd_k_count") or 0),
+                    "escape_count": int(payload.get("escape_count") or 0),
+                }
+            report["classification"] = classify(trace, report["dom"])
+            report["status"] = "complete" if not report["errors"] else "error"
+            AppHelper.stopEventLoop()
+
+        webview.evaluateJavaScript_completionHandler_(js, completed)
+
+    def drive() -> None:
+        try:
+            time.sleep(max(args.settle_seconds, 0.25))
+            DRIVER.key(os.getpid(), "cmd-k")
+            time.sleep(0.75)
+            DRIVER.key(os.getpid(), "escape")
+            time.sleep(0.75)
+        except AccessibilityPermissionRequired as exc:
+            report["status"] = "blocked_permission"
+            report["errors"].append(type(exc).__name__)
+        except UIAutomationError as exc:
+            report["errors"].append(f"ui_automation:{type(exc).__name__}")
+        except Exception as exc:  # pragma: no cover - target-Mac only
+            report["errors"].append(f"{type(exc).__name__}:{exc}")
+        finally:
+            AppHelper.callAfter(finalize_on_main)
+
+    threading.Thread(target=drive, daemon=True).start()
+
+    try:
+        AppHelper.runEventLoop()
+    finally:
+        NSEvent.removeMonitor_(monitor)
+        window.orderOut_(None)
+        DRIVER.close()
+
+    report["finished_at"] = datetime.now(timezone.utc).isoformat()
+    output.write_text(json.dumps(report, indent=2, sort_keys=True) + "\n", encoding="utf-8")
+    print(json.dumps(report, indent=2, sort_keys=True))
+    print(f"Evidence: {output}")
+
+    if report["status"] == "blocked_permission":
+        return 2
+    return 0 if report["status"] == "complete" else 1
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/test/test_macos_keyboard_event_path_probe_contract.py b/test/test_macos_keyboard_event_path_probe_contract.py
new file mode 100644
index 0000000..01d20c6
--- /dev/null
+++ b/test/test_macos_keyboard_event_path_probe_contract.py
@@ -0,0 +1,45 @@
+from __future__ import annotations
+
+import unittest
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+PROBE = ROOT / "scripts" / "diagnose_macos_keyboard_event_path.py"
+
+
+class MacOSKeyboardEventPathProbeContractTest(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls) -> None:
+        cls.probe = PROBE.read_text(encoding="utf-8")
+
+    def test_probe_uses_same_pid_targeted_driver_and_appkit_monitor_shape(self) -> None:
+        self.assertIn('DRIVER.key(os.getpid(), "cmd-k")', self.probe)
+        self.assertIn('DRIVER.key(os.getpid(), "escape")', self.probe)
+        self.assertIn("NSEvent.addLocalMonitorForEventsMatchingMask_handler_", self.probe)
+        self.assertIn("NSEventMaskKeyDown", self.probe)
+        self.assertIn("NSEventModifierFlagCommand", self.probe)
+        self.assertIn("key_code == 40 or semantic_k", self.probe)
+        self.assertIn("key_code == 53", self.probe)
+
+    def test_probe_discriminates_monitor_bridge_and_dom_boundaries(self) -> None:
+        self.assertIn('"event": "monitor_received"', self.probe)
+        self.assertIn('"event": "cmd_k_matched"', self.probe)
+        self.assertIn('"event": "bridge_requested"', self.probe)
+        self.assertIn('"event": "bridge_completion"', self.probe)
+        self.assertIn("defaultPrevented", self.probe)
+        self.assertIn("cmd_k_count", self.probe)
+        self.assertIn("pid_targeted_cmd_k_did_not_reach_local_monitor", self.probe)
+        self.assertIn("cmd_k_matched_but_webview_bridge_did_not_complete", self.probe)
+        self.assertIn("cmd_k_bridge_completed_but_dom_listener_not_reached", self.probe)
+
+    def test_probe_is_diagnostic_only_and_privacy_bounded(self) -> None:
+        self.assertIn('"qualification_scope": "diagnostic_only"', self.probe)
+        self.assertIn("does not launch ClosedRoom", self.probe)
+        self.assertNotIn("/v1/meetings", self.probe)
+        self.assertNotIn("transcript", self.probe.lower())
+        self.assertNotIn("recording.wav", self.probe)
+
+
+if __name__ == "__main__":
+    unittest.main()