fix(macos): forward launcher CLI arguments and preserve MCP stdio

docs/automation/mcp_handshake.py

@@ -0,0 +1,90 @@
+"""Bounded stdio regression probe; point this at the packaged launcher on macOS."""
+import json
+import os
+from pathlib import Path
+import queue
+import signal
+import subprocess
+import sys
+import tempfile
+import threading
+
+
+def probe(command: list[str], timeout: float = 10) -> None:
+    # A separate process group lets a failed probe clean up a broken launcher
+    # and any GUI child it incorrectly spawned. Never touch existing editors.
+    with tempfile.TemporaryFile() as stderr:
+        process = subprocess.Popen(
+            [*command, "--mcp"],
+            stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=stderr,
+            text=True, encoding="utf-8", start_new_session=os.name == "posix",
+            env={**os.environ, "OCS_SKIP_SCHEMA_SYNC": "1"},
+        )
+        lines = queue.Queue()
+
+        def read_stdout() -> None:
+            try:
+                for line in process.stdout:
+                    lines.put(line)
+            finally:
+                lines.put(None)
+
+        threading.Thread(target=read_stdout, daemon=True).start()
+
+        def request(request_id: int, method: str, params: dict) -> dict:
+            process.stdin.write(json.dumps({
+                "jsonrpc": "2.0", "id": request_id,
+                "method": method, "params": params,
+            }) + "\n")
+            process.stdin.flush()
+            # stdin stays open while waiting: a server buffering until EOF
+            # must fail this test just like the launcher that ignores --mcp.
+            try:
+                line = lines.get(timeout=timeout)
+            except queue.Empty as error:
+                raise AssertionError(f"Timed out waiting for {method}") from error
+            assert line is not None, f"stdout closed before {method} responded"
+            response = json.loads(line)
+            assert response["jsonrpc"] == "2.0", response
+            assert response["id"] == request_id, response
+            assert "error" not in response, response
+            return response["result"]
+
+        try:
+            initialized = request(1, "initialize", {
+                "protocolVersion": "2025-11-25", "capabilities": {},
+                "clientInfo": {"name": "packaged-handshake", "version": "1"},
+            })
+            assert initialized["protocolVersion"] == "2025-11-25", initialized
+            assert initialized["serverInfo"]["name"] == "OpenCADStudio", initialized
+            process.stdin.write(
+                '{"jsonrpc":"2.0","method":"notifications/initialized"}\n'
+            )
+            process.stdin.flush()
+            tools = request(2, "tools/list", {})
+            assert {tool["name"] for tool in tools["tools"]} == {
+                "ocs_sessions", "ocs_read", "ocs_execute", "ocs_capture",
+            }, tools
+            request(3, "ping", {})
+            process.stdin.close()
+            assert process.wait(timeout=timeout) == 0, process.returncode
+        finally:
+            if os.name == "posix":
+                try:
+                    os.killpg(process.pid, signal.SIGKILL)
+                except ProcessLookupError:
+                    pass
+            elif process.poll() is None:
+                process.kill()
+            process.wait(timeout=5)
+            process.stdin.close()
+            process.stdout.close()
+            stderr.seek(0)
+            diagnostics = stderr.read().decode("utf-8", errors="replace")
+            if diagnostics:
+                print(diagnostics, file=sys.stderr, end="")
+
+
+if __name__ == "__main__":
+    probe([str(Path(sys.argv[1]).resolve())])
+    print("MCP initialize, tools/list, ping and EOF shutdown passed")