From 9c1dd9ca92fa683c1788e8b4b0c9761f165f619f Mon Sep 17 00:00:00 2001
From: "Saloni (Mac)" <salonivashisht6564@gmail.com>
Date: Fri, 8 May 2026 17:16:52 +0530
Subject: [PATCH] fix: reject invalid explicit frequency config

---
 src/sktime_mcp/data/adapters/file_adapter.py  |  4 +-
 .../data/adapters/pandas_adapter.py           |  5 +-
 tests/test_data_frequency_validation.py       | 67 +++++++++++++++++++
 3 files changed, 73 insertions(+), 3 deletions(-)
 create mode 100644 tests/test_data_frequency_validation.py

diff --git a/src/sktime_mcp/data/adapters/file_adapter.py b/src/sktime_mcp/data/adapters/file_adapter.py
index 30c3b8d5..9560e65e 100644
--- a/src/sktime_mcp/data/adapters/file_adapter.py
+++ b/src/sktime_mcp/data/adapters/file_adapter.py
@@ -100,8 +100,10 @@ def load(self) -> pd.DataFrame:
         # Set frequency if specified
         freq = self.config.get("frequency")
         if freq:
-            with contextlib.suppress(Exception):
+            try:
                 df = df.asfreq(freq)
+            except Exception as e:
+                raise ValueError(f"Invalid frequency '{freq}': {e}") from e
 
         self._data = df
 
diff --git a/src/sktime_mcp/data/adapters/pandas_adapter.py b/src/sktime_mcp/data/adapters/pandas_adapter.py
index 7607d5e9..a1abbedd 100644
--- a/src/sktime_mcp/data/adapters/pandas_adapter.py
+++ b/src/sktime_mcp/data/adapters/pandas_adapter.py
@@ -5,7 +5,6 @@
 time index detection and validation.
 """
 
-import contextlib
 from typing import Any
 
 import pandas as pd
@@ -72,8 +71,10 @@ def load(self) -> pd.DataFrame:
         # Infer or set frequency
         freq = self.config.get("frequency")
         if freq:
-            with contextlib.suppress(Exception):
+            try:
                 df = df.asfreq(freq)
+            except Exception as e:
+                raise ValueError(f"Invalid frequency '{freq}': {e}") from e
         elif isinstance(df.index, pd.DatetimeIndex) and df.index.freq is None:
             # Try to infer frequency
             inferred_freq = pd.infer_freq(df.index)
diff --git a/tests/test_data_frequency_validation.py b/tests/test_data_frequency_validation.py
new file mode 100644
index 00000000..0f8dbd55
--- /dev/null
+++ b/tests/test_data_frequency_validation.py
@@ -0,0 +1,67 @@
+"""Tests for explicit frequency validation in data adapters."""
+
+from pathlib import Path
+
+import pytest
+
+from sktime_mcp.data.adapters.file_adapter import FileAdapter
+from sktime_mcp.data.adapters.pandas_adapter import PandasAdapter
+
+
+def test_pandas_adapter_rejects_invalid_explicit_frequency():
+    """Invalid user-provided frequency should fail instead of being ignored."""
+    adapter = PandasAdapter(
+        {
+            "type": "pandas",
+            "data": {
+                "date": ["2020-01-01", "2020-01-02", "2020-01-03"],
+                "value": [1, 2, 3],
+            },
+            "time_column": "date",
+            "target_column": "value",
+            "frequency": "not_a_freq",
+        }
+    )
+
+    with pytest.raises(ValueError, match="Invalid frequency 'not_a_freq'"):
+        adapter.load()
+
+
+def test_file_adapter_rejects_invalid_explicit_frequency(tmp_path: Path):
+    """Invalid explicit frequency should fail for file-backed data too."""
+    path = tmp_path / "series.csv"
+    path.write_text("date,value\n2020-01-01,1\n2020-01-02,2\n2020-01-03,3\n")
+
+    adapter = FileAdapter(
+        {
+            "type": "file",
+            "path": str(path),
+            "time_column": "date",
+            "target_column": "value",
+            "frequency": "not_a_freq",
+        }
+    )
+
+    with pytest.raises(ValueError, match="Invalid frequency 'not_a_freq'"):
+        adapter.load()
+
+
+def test_pandas_adapter_applies_valid_explicit_frequency():
+    """Valid explicit frequency should still be applied normally."""
+    adapter = PandasAdapter(
+        {
+            "type": "pandas",
+            "data": {
+                "date": ["2020-01-01", "2020-01-03"],
+                "value": [1, 3],
+            },
+            "time_column": "date",
+            "target_column": "value",
+            "frequency": "D",
+        }
+    )
+
+    data = adapter.load()
+
+    assert len(data) == 3
+    assert data.index.freqstr == "D"