diff --git a/crates/attractor/src/validation/rules.rs b/crates/attractor/src/validation/rules.rs
index e45df775b..971eb34fe 100644
--- a/crates/attractor/src/validation/rules.rs
+++ b/crates/attractor/src/validation/rules.rs
@@ -94,12 +94,24 @@ impl LintRule for TerminalNodeRule {
             return vec![Diagnostic {
                 rule: self.name().to_string(),
                 severity: Severity::Error,
-                message: "Pipeline must have at least one terminal node (shape=Msquare or id exit/end)".to_string(),
+                message: "Pipeline must have exactly one terminal node (shape=Msquare or id exit/end)".to_string(),
                 node_id: None,
                 edge: None,
                 fix: Some("Add a node with shape=Msquare or id 'exit'/'end'".to_string()),
             }];
         }
+        if terminal_count > 1 {
+            return vec![Diagnostic {
+                rule: self.name().to_string(),
+                severity: Severity::Error,
+                message: format!(
+                    "Pipeline must have exactly one terminal node, found {terminal_count}"
+                ),
+                node_id: None,
+                edge: None,
+                fix: Some("Remove extra terminal nodes so exactly one remains".to_string()),
+            }];
+        }
         Vec::new()
     }
 }