diff --git a/lib/crates/arc-llm/src/catalog.json b/lib/crates/arc-llm/src/catalog.json
index 6eed087ae..b17f9ed72 100644
--- a/lib/crates/arc-llm/src/catalog.json
+++ b/lib/crates/arc-llm/src/catalog.json
@@ -194,6 +194,22 @@
     "aliases": ["gemini-pro"],
     "default": true
   },
+  {
+    "id": "gemini-3.1-pro-preview-customtools",
+    "provider": "gemini",
+    "family": "gemini-3",
+    "display_name": "Gemini 3.1 Pro Custom Tools (Preview)",
+    "limits": { "context_window": 1048576, "max_output": 65536 },
+    "training": "2025-01-01",
+    "features": { "tools": true, "vision": true, "reasoning": true },
+    "costs": {
+      "input_cost_per_mtok": 2.0,
+      "output_cost_per_mtok": 12.0,
+      "cache_input_cost_per_mtok": 0.50
+    },
+    "estimated_output_tps": 85,
+    "aliases": ["gemini-customtools"]
+  },
   {
     "id": "gemini-3-flash-preview",
     "provider": "gemini",
diff --git a/lib/crates/arc-llm/src/catalog.rs b/lib/crates/arc-llm/src/catalog.rs
index d907f1544..d4f6f75e8 100644
--- a/lib/crates/arc-llm/src/catalog.rs
+++ b/lib/crates/arc-llm/src/catalog.rs
@@ -278,7 +278,7 @@ mod tests {
         assert_eq!(openai.len(), 7);
 
         let gemini = list_models(Some("gemini"));
-        assert_eq!(gemini.len(), 3);
+        assert_eq!(gemini.len(), 4);
 
         let unknown = list_models(Some("unknown"));
         assert!(unknown.is_empty());