Use built-in agent preset defaults

internal/harness/scenarios/idle_screen_permission_prompt.json

@@ -0,0 +1,37 @@
+{
+  "name": "idle_screen_permission_prompt",
+  "presets": {
+    "processes": [
+      {
+        "name": "screen-permission",
+        "argv": [
+          "sh",
+          "-lc",
+          "printf '\\033[2J\\033[HCalling patterm...\\n\\nTool use\\n\\nDo you want to proceed?\\n  1. Yes\\n'; i=0; while [ $i -lt 300 ]; do printf '\\033[HCalling patterm... %03d' $i; i=$((i+1)); done; sleep 60"
+        ],
+        "idle_detection": {
+          "strategy": "output_activity",
+          "idle_threshold_ms": 500,
+          "permission_patterns": ["Do you want to proceed\\?"]
+        }
+      }
+    ]
+  },
+  "trust": ["screen-permission"],
+  "steps": [
+    {
+      "type": "mcp_call",
+      "method": "spawn_process",
+      "params": {"kind": "command", "preset": "screen-permission", "name": "screen-permission"},
+      "save_as": "proc"
+    },
+    {
+      "type": "wait_until_mcp",
+      "method": "get_process_status",
+      "params": {"process_id": "{{proc.process_id}}"},
+      "path": "idle_state",
+      "equals": "permission",
+      "timeout_ms": 4000
+    }
+  ]
+}