diff --git a/backend/apps/events/adapters/heal_trigger.py b/backend/apps/events/adapters/heal_trigger.py
index 6e3f45eb..5f937083 100644
--- a/backend/apps/events/adapters/heal_trigger.py
+++ b/backend/apps/events/adapters/heal_trigger.py
@@ -44,6 +44,16 @@ def parse_heal_reply(text: str) -> Tuple[Optional[str], str]:
     return fix, reason
 
 
+async def probe_url(url: str) -> bool:
+    """A heal is only real if the fix demonstrably answers: SSRF-guarded GET, 2xx/3xx required. Model claims never applied unverified."""
+    try:
+        from backend.apps.agents.tools.web import USER_AGENT, safe_fetch
+        resp = await safe_fetch(url, method="GET", headers={"User-Agent": USER_AGENT}, timeout=12.0)
+        return resp.status_code < 400
+    except Exception:
+        return False
+
+
 async def attempt_heal(workflow_id: str, trigger: EventTriggerConfig) -> bool:
     """True when the trigger config was repaired (caller should re-poll now)."""
     from backend.apps.events import stores
@@ -63,6 +73,12 @@ async def attempt_heal(workflow_id: str, trigger: EventTriggerConfig) -> bool:
         logger.warning("heal turn failed for trigger %s: %s", trigger.id, e)
         return False
     if fix and fix.startswith("http") and fix != url:
+        if not await probe_url(fix):
+            stores.append_log(workflow_id, EventLogEntry(
+                trigger_id=trigger.id, kind="error",
+                summary=f"Self-heal proposed {fix} but it didn't answer; not applied",
+            ))
+            return False
         wf = storage.get_workflow(workflow_id)
         if wf is None:
             return False
diff --git a/backend/tests/test_event_stream_tier.py b/backend/tests/test_event_stream_tier.py
index b708f5dd..c5c44228 100644
--- a/backend/tests/test_event_stream_tier.py
+++ b/backend/tests/test_event_stream_tier.py
@@ -176,6 +176,10 @@ def test_self_heal_fixes_url_or_escalates(make_wf, monkeypatch):
         assert "https://old.example/feed" in prompt and "410 Gone" in prompt
         return "Investigated.\nFIX_URL: https://new.example/feed"
 
+    async def p_probe_ok(url):
+        return url == "https://new.example/feed"
+
+    monkeypatch.setattr(ht, "probe_url", p_probe_ok)
     monkeypatch.setattr(ac, "run_check_turn", p_fix_turn)
     assert p_run(ht.attempt_heal(wf.id, trig)) is True
     healed = storage.get_workflow(wf.id).event_triggers[0]
@@ -190,3 +194,27 @@ def test_self_heal_fixes_url_or_escalates(make_wf, monkeypatch):
     assert p_run(ht.attempt_heal(wf.id, healed)) is False
     assert storage.get_workflow(wf.id).event_triggers[0].source.url == "https://new.example/feed"  # untouched
     assert any("requires a sign-in" in e.summary for e in stores.read_log(wf.id))
+
+
+def test_heal_never_applies_an_unverified_fix(make_wf, monkeypatch):
+    """The model can claim any URL; only one that actually answers gets applied."""
+    from backend.apps.events.adapters import agent_check as ac
+    from backend.apps.events.adapters import heal_trigger as ht
+    from backend.apps.events import stores
+    from backend.apps.workflows import storage
+
+    trig = EventTriggerConfig(source=StreamSource(url="https://old.example/feed"))
+    wf = make_wf(event_triggers=[trig])
+    storage.save_workflow(wf)
+
+    async def p_fix_turn(model, prompt, **kwargs):
+        return "FIX_URL: https://hallucinated.example/feed"
+
+    async def p_probe_dead(url):
+        return False
+
+    monkeypatch.setattr(ac, "run_check_turn", p_fix_turn)
+    monkeypatch.setattr(ht, "probe_url", p_probe_dead)
+    assert p_run(ht.attempt_heal(wf.id, trig)) is False
+    assert storage.get_workflow(wf.id).event_triggers[0].source.url == "https://old.example/feed"
+    assert any("didn't answer; not applied" in e.summary for e in stores.read_log(wf.id))