Merge pull request #1167 from arnoldwender/fix/kg-date-validation

fix(kg): validate ISO-8601 date formats at MCP boundary

Author: igorls

mempalace/config.py

@@ -81,6 +81,38 @@ def sanitize_kg_value(value: str, field_name: str = "value") -> str:
     return value
 
 
+# ISO-8601 date validator for knowledge-graph temporal parameters
+# (as_of, valid_from, valid_to, ended). Parameterized queries already
+# prevent SQL injection, but unvalidated date strings silently miss
+# every row — callers cannot distinguish "no fact at this time" from
+# "your date format was unrecognized." Require full YYYY-MM-DD: KG
+# queries compare TEXT dates lexicographically, so partials like "2026"
+# would re-introduce silent empty results (e.g. "2026-01-01" <= "2026"
+# is False), defeating the purpose of validation.
+_ISO_DATE_RE = re.compile(r"^\d{4}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12]\d|3[01])$")
+
+
+def sanitize_iso_date(value, field_name: str = "date"):
+    """Validate an ISO-8601 date string, accepting None or empty as-is.
+
+    Accepts only ``YYYY-MM-DD``. Raises ValueError on any other
+    non-empty input so the MCP layer can surface a clear error to the
+    caller instead of silently returning empty results. Partial dates
+    (``YYYY``, ``YYYY-MM``) are rejected because KG queries compare
+    TEXT dates lexicographically and would silently exclude valid facts.
+    """
+    if value is None or value == "":
+        return value
+    if not isinstance(value, str):
+        raise ValueError(f"{field_name} must be a string")
+    value = value.strip()
+    if not _ISO_DATE_RE.match(value):
+        raise ValueError(
+            f"{field_name}={value!r} is not a valid ISO-8601 date " f"(expected YYYY-MM-DD)"
+        )
+    return value
+
+
 def sanitize_content(value: str, max_length: int = 100_000) -> str:
     """Validate drawer/diary content length."""
     if not isinstance(value, str) or not value.strip():

mempalace/mcp_server.py

@@ -55,6 +55,7 @@
     sanitize_kg_value,
     sanitize_name,
     sanitize_content,
+    sanitize_iso_date,
 )
 from .version import __version__  # noqa: E402
 from chromadb.errors import NotFoundError as _ChromaNotFoundError  # noqa: E402
@@ -1059,6 +1060,7 @@ def tool_kg_query(entity: str, as_of: str = None, direction: str = "both"):
     """Query the knowledge graph for an entity's relationships."""
     try:
         entity = sanitize_kg_value(entity, "entity")
+        as_of = sanitize_iso_date(as_of, "as_of")
     except ValueError as e:
         return {"error": str(e)}
     if direction not in ("outgoing", "incoming", "both"):
@@ -1092,6 +1094,7 @@ def tool_kg_add(
         subject = sanitize_kg_value(subject, "subject")
         predicate = sanitize_name(predicate, "predicate")
         object = sanitize_kg_value(object, "object")
+        valid_from = sanitize_iso_date(valid_from, "valid_from")
     except ValueError as e:
         return {"success": False, "error": str(e)}
 
@@ -1135,6 +1138,7 @@ def tool_kg_invalidate(subject: str, predicate: str, object: str, ended: str = N
         subject = sanitize_kg_value(subject, "subject")
         predicate = sanitize_name(predicate, "predicate")
         object = sanitize_kg_value(object, "object")
+        ended = sanitize_iso_date(ended, "ended")
     except ValueError as e:
         return {"success": False, "error": str(e)}
     resolved_ended = ended or date.today().isoformat()

tests/test_config.py

@@ -3,7 +3,13 @@
 import tempfile
 
 import pytest
-from mempalace.config import MempalaceConfig, normalize_wing_name, sanitize_kg_value, sanitize_name
+from mempalace.config import (
+    MempalaceConfig,
+    normalize_wing_name,
+    sanitize_iso_date,
+    sanitize_kg_value,
+    sanitize_name,
+)
 
 
 def test_default_config():
@@ -212,3 +218,69 @@ def test_kg_value_rejects_null_bytes():
 def test_kg_value_rejects_over_length():
     with pytest.raises(ValueError):
         sanitize_kg_value("a" * 129)
+
+
+# --- sanitize_iso_date ---
+
+
+def test_iso_date_rejects_year_only():
+    # Partial dates re-introduce silent empty result sets via lexicographic
+    # TEXT comparison in KG queries (e.g. "2026-01-01" <= "2026" is False).
+    with pytest.raises(ValueError):
+        sanitize_iso_date("2026")
+
+
+def test_iso_date_rejects_year_month():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("2026-03")
+
+
+def test_iso_date_accepts_full_date():
+    assert sanitize_iso_date("2026-03-15") == "2026-03-15"
+
+
+def test_iso_date_passes_through_none():
+    assert sanitize_iso_date(None) is None
+
+
+def test_iso_date_passes_through_empty_string():
+    assert sanitize_iso_date("") == ""
+
+
+def test_iso_date_strips_whitespace():
+    assert sanitize_iso_date("  2026-03-15  ") == "2026-03-15"
+
+
+def test_iso_date_rejects_natural_language():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("March 2026")
+
+
+def test_iso_date_rejects_abbreviated_month():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("Jan 2025")
+
+
+def test_iso_date_rejects_us_format():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("03/15/2026")
+
+
+def test_iso_date_rejects_invalid_month():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("2026-13")
+
+
+def test_iso_date_rejects_invalid_day():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("2026-02-32")
+
+
+def test_iso_date_rejects_non_string():
+    with pytest.raises(ValueError):
+        sanitize_iso_date(20260315)
+
+
+def test_iso_date_error_names_field():
+    with pytest.raises(ValueError, match="valid_from"):
+        sanitize_iso_date("yesterday", "valid_from")

tests/test_mcp_server.py

@@ -788,6 +788,59 @@ def test_kg_stats(self, monkeypatch, config, palace_path, seeded_kg):
         result = tool_kg_stats()
         assert result["entities"] >= 4
 
+    # --- Date validation at the MCP boundary (issue #1164) ---
+
+    def test_kg_add_rejects_invalid_valid_from(self, monkeypatch, config, palace_path, kg):
+        _patch_mcp_server(monkeypatch, config, kg)
+        from mempalace.mcp_server import tool_kg_add
+
+        result = tool_kg_add(
+            subject="Alice",
+            predicate="likes",
+            object="coffee",
+            valid_from="Jan 2025",
+        )
+        assert result["success"] is False
+        assert "valid_from" in result["error"]
+        assert "ISO-8601" in result["error"]
+
+    def test_kg_query_rejects_invalid_as_of(self, monkeypatch, config, palace_path, seeded_kg):
+        _patch_mcp_server(monkeypatch, config, seeded_kg)
+        from mempalace.mcp_server import tool_kg_query
+
+        result = tool_kg_query(entity="Max", as_of="March 2026")
+        assert "error" in result
+        assert "as_of" in result["error"]
+
+    def test_kg_invalidate_rejects_invalid_ended(self, monkeypatch, config, palace_path, seeded_kg):
+        _patch_mcp_server(monkeypatch, config, seeded_kg)
+        from mempalace.mcp_server import tool_kg_invalidate
+
+        result = tool_kg_invalidate(
+            subject="Max",
+            predicate="does",
+            object="chess",
+            ended="yesterday",
+        )
+        assert result["success"] is False
+        assert "ended" in result["error"]
+
+    def test_kg_query_rejects_partial_iso_dates(self, monkeypatch, config, palace_path, seeded_kg):
+        _patch_mcp_server(monkeypatch, config, seeded_kg)
+        from mempalace.mcp_server import tool_kg_query
+
+        # Partial ISO dates are rejected: KG queries compare TEXT dates
+        # lexicographically, so "2026-01-01" <= "2026" is False, which
+        # silently excludes facts. Reject at the boundary — only YYYY-MM-DD
+        # produces correct results.
+        for value in ("2026", "2026-03"):
+            result = tool_kg_query(entity="Max", as_of=value)
+            assert "error" in result, f"accepted partial date {value!r}: {result}"
+
+        # Full ISO-8601 dates still pass.
+        result = tool_kg_query(entity="Max", as_of="2026-03-15")
+        assert "error" not in result, f"rejected valid date: {result}"
+
 
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