From 1ee9747551e561606dde7b25d8f7ce8c755cc7fc Mon Sep 17 00:00:00 2001
From: Yiorgis Gozadinos <ggozadinos@gmail.com>
Date: Tue, 24 Feb 2026 12:11:20 +0200
Subject: [PATCH] Catch MontyRuntimeError from Monty() constructor

---
 haiku_rag_slim/haiku/rag/agents/rlm/sandbox.py | 5 ++++-
 tests/agents/rlm/test_sandbox.py               | 7 +++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/haiku_rag_slim/haiku/rag/agents/rlm/sandbox.py b/haiku_rag_slim/haiku/rag/agents/rlm/sandbox.py
index 16c6511b..f845a097 100644
--- a/haiku_rag_slim/haiku/rag/agents/rlm/sandbox.py
+++ b/haiku_rag_slim/haiku/rag/agents/rlm/sandbox.py
@@ -162,7 +162,10 @@ class Sandbox:
                 inputs=input_names,
                 external_functions=list(external_fns.keys()),
             )
-        except pydantic_monty.MontySyntaxError as e:
+        except (
+            pydantic_monty.MontySyntaxError,
+            pydantic_monty.MontyRuntimeError,
+        ) as e:
             return SandboxResult(stdout="", stderr=str(e), success=False)
 
         stdout_lines: list[str] = []
diff --git a/tests/agents/rlm/test_sandbox.py b/tests/agents/rlm/test_sandbox.py
index 01ecfef0..adc34daa 100644
--- a/tests/agents/rlm/test_sandbox.py
+++ b/tests/agents/rlm/test_sandbox.py
@@ -66,6 +66,13 @@ class TestSandboxErrors:
         assert not result.success
         assert "NameError" in result.stderr
 
+    @pytest.mark.asyncio
+    async def test_multi_module_import(self, sandbox):
+        """Test that unsupported multi-module imports are caught gracefully."""
+        result = await sandbox.execute("import json, string")
+        assert not result.success
+        assert result.stderr != ""
+
 
 class TestSandboxHaikuRAG:
     """Test haiku.rag functions in sandbox."""