diff --git a/hyperglass/models/tests/test_webhook.py b/hyperglass/models/tests/test_webhook.py
new file mode 100644
index 00000000..adf33a4d
--- /dev/null
+++ b/hyperglass/models/tests/test_webhook.py
@@ -0,0 +1,63 @@
+"""Regression tests for the Webhook model validator.
+
+Tracks https://github.com/thatmattlove/hyperglass/issues/282 — Slack / MS Teams
+/ generic HTTP logging silently failed because the `mode="before"` validator
+treated its raw-dict input as a model instance.
+"""
+
+# Standard Library
+from datetime import datetime, timezone
+
+# Project
+from hyperglass.models.webhook import Webhook
+
+
+def _query(source: str, network: dict | None = None) -> dict:
+    return {
+        "query_location": "test",
+        "query_type": "bgp_route",
+        "query_target": "192.0.2.0/24",
+        "headers": {},
+        "source": source,
+        "network": network if network is not None else {"prefix": "192.0.2.0/24", "asn": "65000"},
+        "timestamp": datetime.now(timezone.utc),
+    }
+
+
+def test_webhook_constructs_with_public_source():
+    """The validator must not raise on a normal public-IP source."""
+    hook = Webhook(**_query(source="203.0.113.7"))
+    assert hook.source == "203.0.113.7"
+    assert hook.network.prefix == "192.0.2.0/24"
+    assert hook.network.asn == "65000"
+
+
+def test_webhook_resets_network_for_localhost_v4():
+    """A 127.0.0.1 source should clear the network info to defaults."""
+    hook = Webhook(**_query(source="127.0.0.1"))
+    assert hook.source == "127.0.0.1"
+    # WebhookNetwork defaults all fields to "Unknown" when given an empty dict.
+    assert hook.network.prefix == "Unknown"
+    assert hook.network.asn == "Unknown"
+
+
+def test_webhook_resets_network_for_localhost_v6():
+    """`::1` should also be treated as localhost."""
+    hook = Webhook(**_query(source="::1"))
+    assert hook.network.prefix == "Unknown"
+    assert hook.network.asn == "Unknown"
+
+
+def test_webhook_slack_payload_renders():
+    """End-to-end: the Slack payload must build without raising."""
+    hook = Webhook(**_query(source="203.0.113.7"))
+    payload = hook.slack()
+    assert payload["text"]
+    assert any("203.0.113.7" in str(block) for block in payload["blocks"])
+
+
+def test_webhook_msteams_payload_renders():
+    """End-to-end: the MS Teams payload must build without raising."""
+    hook = Webhook(**_query(source="203.0.113.7"))
+    payload = hook.msteams()
+    assert payload["@type"] == "MessageCard"
diff --git a/hyperglass/models/webhook.py b/hyperglass/models/webhook.py
index 2c831935..ad9385b1 100644
--- a/hyperglass/models/webhook.py
+++ b/hyperglass/models/webhook.py
@@ -58,11 +58,20 @@ class Webhook(HyperglassModel):
     timestamp: datetime
 
     @model_validator(mode="before")
-    def validate_webhook(cls, model: "Webhook") -> "Webhook":
-        """Reset network attributes if the source is localhost."""
-        if model.source in ("127.0.0.1", "::1"):
-            model.network = {}
-        return model
+    @classmethod
+    def validate_webhook(cls, data: t.Any) -> t.Any:
+        """Reset network attributes if the source is localhost.
+
+        `mode="before"` runs prior to model construction, so the input is the
+        raw mapping passed to `Webhook(**query)` (a dict). The previous
+        implementation accessed it as if it were a model instance
+        (`model.source`, `model.network = {}`), which raised
+        `AttributeError: 'dict' object has no attribute 'source'` and
+        silently broke Slack/MS Teams/generic webhook delivery (#282).
+        """
+        if isinstance(data, dict) and data.get("source") in ("127.0.0.1", "::1"):
+            data["network"] = {}
+        return data
 
     def msteams(self) -> t.Dict[str, t.Any]:
         """Format the webhook data as a Microsoft Teams card."""