diff --git a/meshai/config.py b/meshai/config.py
index 0e69f50..00faedc 100644
--- a/meshai/config.py
+++ b/meshai/config.py
@@ -543,7 +543,7 @@ class NotificationToggle:
     severity_channels: dict = field(default_factory=dict)
     # v0.5.2: staleness drop + per-toggle cooldown (Matt's spam fix)
     freshness_seconds: int = 600   # drop events older than this at dispatcher entrance
-    cooldown_seconds: int = 300    # per (toggle, category, region) throttle window
+    cooldown_seconds: int = 0      # per (toggle, category, region) throttle window; 0 = disabled
     # per-channel delivery config (mirrors NotificationRuleConfig channel fields)
     broadcast_channel: Optional[int] = None
     node_ids: list = field(default_factory=list)
diff --git a/meshai/notifications/pipeline/dispatcher.py b/meshai/notifications/pipeline/dispatcher.py
index f56b640..4d2e177 100644
--- a/meshai/notifications/pipeline/dispatcher.py
+++ b/meshai/notifications/pipeline/dispatcher.py
@@ -358,7 +358,12 @@ class Dispatcher:
                 return
 
         # ---------- Section 2 — per-toggle cooldown ----------
-        cooldown_s = int(getattr(tog, "cooldown_seconds", 300) or 0)
+        # Immediate-severity events bypass cooldown entirely — they are
+        # already rate-controlled by source handler change detection.
+        if getattr(event, "severity", None) == "immediate":
+            cooldown_s = 0
+        else:
+            cooldown_s = int(getattr(tog, "cooldown_seconds", 300) or 0)
         if cooldown_s > 0:
             suffix = (event.data or {}).get("_cooldown_suffix", "")
             region_key = event.region or "*"