diff --git a/crates/arc-attractor/src/validation/rules.rs b/crates/arc-attractor/src/validation/rules.rs
index 1e1e9d8e1..dada4c7ed 100644
--- a/crates/arc-attractor/src/validation/rules.rs
+++ b/crates/arc-attractor/src/validation/rules.rs
@@ -4,7 +4,7 @@ use crate::graph::{AttrValue, Graph};
 
 use super::{Diagnostic, LintRule, Severity};
 
-/// Returns all 15 built-in lint rules.
+/// Returns all 16 built-in lint rules.
 #[must_use]
 pub fn built_in_rules() -> Vec<Box<dyn LintRule>> {
     vec![
@@ -23,6 +23,7 @@ pub fn built_in_rules() -> Vec<Box<dyn LintRule>> {
         Box::new(PromptOnLlmNodesRule),
         Box::new(FreeformEdgeCountRule),
         Box::new(DirectionValidRule),
+        Box::new(ReservedKeywordNodeIdRule),
     ]
 }
 
@@ -703,6 +704,42 @@ impl LintRule for DirectionValidRule {
     }
 }
 
+// --- Rule 16: reserved_keyword_node_id (WARNING) ---
+
+struct ReservedKeywordNodeIdRule;
+
+const DOT_RESERVED_KEYWORDS: &[&str] = &[
+    "graph", "digraph", "subgraph", "node", "edge", "strict", "if",
+];
+
+impl LintRule for ReservedKeywordNodeIdRule {
+    fn name(&self) -> &'static str {
+        "reserved_keyword_node_id"
+    }
+
+    fn apply(&self, graph: &Graph) -> Vec<Diagnostic> {
+        graph
+            .nodes
+            .values()
+            .filter(|node| DOT_RESERVED_KEYWORDS.contains(&node.id.to_lowercase().as_str()))
+            .map(|node| Diagnostic {
+                rule: self.name().to_string(),
+                severity: Severity::Warning,
+                message: format!(
+                    "Node ID '{}' is a DOT reserved keyword and may cause parsing failures",
+                    node.id
+                ),
+                node_id: Some(node.id.clone()),
+                edge: None,
+                fix: Some(format!(
+                    "Rename '{}' to '{}_step' or another non-reserved ID",
+                    node.id, node.id.to_lowercase()
+                )),
+            })
+            .collect()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -2164,4 +2201,58 @@ mod tests {
         let d = rule.apply(&g);
         assert!(d.is_empty());
     }
+
+    // --- reserved_keyword_node_id tests ---
+
+    #[test]
+    fn reserved_keyword_node_id_warns_on_keyword() {
+        let mut g = minimal_graph();
+        g.nodes
+            .insert("graph".to_string(), Node::new("graph"));
+        g.edges.push(Edge::new("start", "graph"));
+        g.edges.push(Edge::new("graph", "exit"));
+        let rule = ReservedKeywordNodeIdRule;
+        let d = rule.apply(&g);
+        assert_eq!(d.len(), 1);
+        assert_eq!(d[0].severity, Severity::Warning);
+        assert_eq!(d[0].node_id.as_deref(), Some("graph"));
+    }
+
+    #[test]
+    fn reserved_keyword_node_id_case_insensitive() {
+        let mut g = minimal_graph();
+        g.nodes.insert("Node".to_string(), Node::new("Node"));
+        g.nodes.insert("EDGE".to_string(), Node::new("EDGE"));
+        g.edges.push(Edge::new("start", "Node"));
+        g.edges.push(Edge::new("Node", "EDGE"));
+        g.edges.push(Edge::new("EDGE", "exit"));
+        let rule = ReservedKeywordNodeIdRule;
+        let d = rule.apply(&g);
+        assert_eq!(d.len(), 2);
+    }
+
+    #[test]
+    fn reserved_keyword_node_id_normal_id_no_warning() {
+        let g = minimal_graph();
+        let rule = ReservedKeywordNodeIdRule;
+        let d = rule.apply(&g);
+        assert!(d.is_empty());
+    }
+
+    #[test]
+    fn reserved_keyword_node_id_multiple_keywords() {
+        let mut g = minimal_graph();
+        g.nodes
+            .insert("strict".to_string(), Node::new("strict"));
+        g.nodes
+            .insert("digraph".to_string(), Node::new("digraph"));
+        g.nodes.insert("if".to_string(), Node::new("if"));
+        g.edges.push(Edge::new("start", "strict"));
+        g.edges.push(Edge::new("strict", "digraph"));
+        g.edges.push(Edge::new("digraph", "if"));
+        g.edges.push(Edge::new("if", "exit"));
+        let rule = ReservedKeywordNodeIdRule;
+        let d = rule.apply(&g);
+        assert_eq!(d.len(), 3);
+    }
 }
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