diff --git a/nextcloud_mcp_server/models/contacts.py b/nextcloud_mcp_server/models/contacts.py
index 54230b94..d3e0fe37 100644
--- a/nextcloud_mcp_server/models/contacts.py
+++ b/nextcloud_mcp_server/models/contacts.py
@@ -1,8 +1,9 @@
 """Pydantic models for Contacts app responses."""
 
+from datetime import date, datetime
 from typing import Any, Dict, List, Optional
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, field_validator
 
 from .base import BaseResponse, StatusResponse
 
@@ -57,6 +58,21 @@ class Contact(BaseModel):
     )
     etag: Optional[str] = Field(None, description="ETag for versioning")
 
+    @field_validator("birthday", mode="before")
+    @classmethod
+    def _coerce_birthday(cls, value: Any) -> Any:
+        """Accept ``date``/``datetime`` from vobject and serialise to ISO string.
+
+        vobject parses BDAY into ``datetime.date`` (or ``datetime.datetime``);
+        the Pydantic model stores it as ``str``. Without this coercion any
+        contact with a populated BDAY blew up the entire ``list_contacts``
+        response (#704, #672). Strings and ``None`` pass through unchanged so
+        callers can still construct contacts with raw ISO input.
+        """
+        if isinstance(value, (date, datetime)):
+            return value.isoformat()
+        return value
+
     @property
     def primary_email(self) -> Optional[str]:
         """Get the primary email address."""
diff --git a/nextcloud_mcp_server/models/tables.py b/nextcloud_mcp_server/models/tables.py
index 32e49c2c..735a78e6 100644
--- a/nextcloud_mcp_server/models/tables.py
+++ b/nextcloud_mcp_server/models/tables.py
@@ -72,7 +72,12 @@ class Table(BaseModel):
     title: str = Field(description="Table title")
     emoji: Optional[str] = Field(None, description="Table emoji")
     ownership: str = Field(description="Table ownership")
-    owner_display_name: str = Field(description="Display name of table owner")
+    # Tables app v2.0.1 stopped emitting owner_display_name at the top level
+    # (still present inside views via get_schema). Optional avoids a 100% failure
+    # rate on list_tables — see #728.
+    owner_display_name: Optional[str] = Field(
+        None, description="Display name of table owner"
+    )
     created_by: Optional[str] = Field(None, description="User who created the table")
     created_at: Optional[str] = Field(None, description="Table creation timestamp")
     last_edit_by: Optional[str] = Field(
diff --git a/tests/unit/test_response_models.py b/tests/unit/test_response_models.py
index 672e730f..856d4192 100644
--- a/tests/unit/test_response_models.py
+++ b/tests/unit/test_response_models.py
@@ -1,6 +1,6 @@
 """Unit tests for Pydantic response models."""
 
-from datetime import date
+from datetime import date, datetime
 
 import pytest
 
@@ -18,6 +18,7 @@ from nextcloud_mcp_server.models.semantic import (
     SamplingSearchResponse,
     SemanticSearchResult,
 )
+from nextcloud_mcp_server.models.tables import Table
 from nextcloud_mcp_server.server.calendar import _event_dict_to_summary
 from nextcloud_mcp_server.server.contacts import _raw_contact_to_model
 
@@ -677,3 +678,76 @@ def test_event_dict_to_summary_calendar_name_without_display_name():
 
     assert summary.calendar_name == "personal"
     assert summary.calendar_display_name == "personal"
+
+
+# ----------------------------------------------------------------------------
+# Direct Contact() construction with date-typed birthday — pins #704 / #672
+# ----------------------------------------------------------------------------
+# These bypass _raw_contact_to_model and hit the Pydantic validator directly,
+# so any future code path that constructs Contact from raw vobject output is
+# covered without depending on the upstream coercion in server/contacts.py.
+
+
+@pytest.mark.unit
+def test_contact_model_coerces_date_birthday_to_iso():
+    """Regression for #704: a datetime.date birthday must coerce to ISO str
+    rather than raise a Pydantic ValidationError.
+    """
+    contact = Contact(uid="c1", fn="Date BDay", birthday=date(2000, 1, 1))
+    assert contact.birthday == "2000-01-01"
+
+
+@pytest.mark.unit
+def test_contact_model_coerces_datetime_birthday_to_iso():
+    """A datetime.datetime input is also valid in vobject output and must coerce."""
+    contact = Contact(
+        uid="c2", fn="DateTime BDay", birthday=datetime(2000, 1, 1, 12, 30)
+    )
+    assert contact.birthday == "2000-01-01T12:30:00"
+
+
+@pytest.mark.unit
+def test_contact_model_string_birthday_passes_through():
+    """ISO strings must round-trip unchanged — the validator should be a no-op."""
+    contact = Contact(uid="c3", fn="String BDay", birthday="1990-05-15")
+    assert contact.birthday == "1990-05-15"
+
+
+@pytest.mark.unit
+def test_contact_model_none_birthday_is_allowed():
+    contact = Contact(uid="c4", fn="No BDay")
+    assert contact.birthday is None
+
+
+# ----------------------------------------------------------------------------
+# Table model parses without owner_display_name — pins #728
+# ----------------------------------------------------------------------------
+
+
+@pytest.mark.unit
+def test_table_parses_without_owner_display_name():
+    """Tables app v2.0.1 dropped owner_display_name from the top-level payload.
+    Parsing must succeed (#728) — anything else 100%-fails nc_tables_list_tables.
+    """
+    raw = {
+        "id": 1,
+        "title": "Welcome to Nextcloud Tables!",
+        "ownership": "alice",
+        # owner_display_name intentionally absent
+    }
+    table = Table(**raw)
+    assert table.id == 1
+    assert table.owner_display_name is None
+
+
+@pytest.mark.unit
+def test_table_parses_with_owner_display_name():
+    """When the field is present we still capture it — Optional doesn't drop data."""
+    raw = {
+        "id": 2,
+        "title": "Old API Table",
+        "ownership": "bob",
+        "owner_display_name": "Bob the Builder",
+    }
+    table = Table(**raw)
+    assert table.owner_display_name == "Bob the Builder"