feat(core): add note_content tenant schema primitive

- add the shared note_content model, migration, and repository

- cover CRUD, migration, and Postgres-backed repository behavior

- fix the Alembic async fallback coroutine warning

Signed-off-by: phernandez <paul@basicmachines.co>

Author: phernandez

src/basic_memory/alembic/env.py

@@ -118,6 +118,54 @@ async def run_async_migrations(connectable):
     await connectable.dispose()
 
 
+def _run_async_migrations_with_asyncio_run(connectable) -> None:
+    """Run async migrations with asyncio.run while closing failed coroutines.
+
+    Trigger: asyncio.run() may reject execution when another event loop is already active.
+    Why: Python raises before awaiting the coroutine, which otherwise leaks a
+    RuntimeWarning about an un-awaited coroutine.
+    Outcome: close the pending coroutine before bubbling the RuntimeError to the
+    fallback path.
+    """
+    migration_coro = run_async_migrations(connectable)
+    try:
+        asyncio.run(migration_coro)
+    except RuntimeError:
+        migration_coro.close()
+        raise
+
+
+def _run_async_migrations_in_thread(connectable) -> None:
+    """Run async migrations in a dedicated thread with its own event loop."""
+    import concurrent.futures
+
+    def run_in_thread():
+        """Run async migrations in a new event loop in a separate thread."""
+        new_loop = asyncio.new_event_loop()
+        asyncio.set_event_loop(new_loop)
+        try:
+            new_loop.run_until_complete(run_async_migrations(connectable))
+        finally:
+            new_loop.close()
+
+    with concurrent.futures.ThreadPoolExecutor() as executor:
+        future = executor.submit(run_in_thread)
+        future.result()  # Wait for completion and re-raise any exceptions
+
+
+def _run_async_engine_migrations(connectable) -> None:
+    """Run async-engine migrations with a running-loop fallback."""
+    try:
+        _run_async_migrations_with_asyncio_run(connectable)
+    except RuntimeError as e:
+        if "cannot be called from a running event loop" in str(e):
+            # We're in a running event loop (likely uvloop or Python 3.14+ tests).
+            # Switch to a dedicated thread so Alembic can finish without nesting loops.
+            _run_async_migrations_in_thread(connectable)
+        else:
+            raise
+
+
 def run_migrations_online() -> None:
     """Run migrations in 'online' mode.
 
@@ -148,30 +196,10 @@ def run_migrations_online() -> None:
 
     # Handle async engines (PostgreSQL with asyncpg)
     if isinstance(connectable, AsyncEngine):
-        # Try to run async migrations
-        # nest_asyncio allows asyncio.run() from within event loops, but doesn't work with uvloop
-        try:
-            asyncio.run(run_async_migrations(connectable))
-        except RuntimeError as e:
-            if "cannot be called from a running event loop" in str(e):
-                # We're in a running event loop (likely uvloop) - need to use a different approach
-                # Create a new thread to run the async migrations
-                import concurrent.futures
-
-                def run_in_thread():
-                    """Run async migrations in a new event loop in a separate thread."""
-                    new_loop = asyncio.new_event_loop()
-                    asyncio.set_event_loop(new_loop)
-                    try:
-                        new_loop.run_until_complete(run_async_migrations(connectable))
-                    finally:
-                        new_loop.close()
-
-                with concurrent.futures.ThreadPoolExecutor() as executor:
-                    future = executor.submit(run_in_thread)
-                    future.result()  # Wait for completion and re-raise any exceptions
-            else:
-                raise
+        # Trigger: async engines need Alembic work to cross the sync/async boundary.
+        # Why: most callers can use asyncio.run(), but running-loop contexts need a thread fallback.
+        # Outcome: migrations complete without leaking un-awaited coroutines.
+        _run_async_engine_migrations(connectable)
     else:
         # Handle sync engines (SQLite) or sync connections
         if hasattr(connectable, "connect"):

src/basic_memory/alembic/versions/l5g6h7i8j9k0_add_note_content_table.py

@@ -0,0 +1,65 @@
+"""Add note_content table
+
+Revision ID: l5g6h7i8j9k0
+Revises: k4e5f6g7h8i9
+Create Date: 2026-04-04 12:00:00.000000
+
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+
+# revision identifiers, used by Alembic.
+revision: str = "l5g6h7i8j9k0"
+down_revision: Union[str, None] = "k4e5f6g7h8i9"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Create note_content for materialized note content and sync state."""
+    op.create_table(
+        "note_content",
+        sa.Column("entity_id", sa.Integer(), nullable=False),
+        sa.Column("project_id", sa.Integer(), nullable=False),
+        sa.Column("external_id", sa.String(), nullable=False),
+        sa.Column("file_path", sa.String(), nullable=False),
+        sa.Column("markdown_content", sa.Text(), nullable=False),
+        sa.Column("db_version", sa.BigInteger(), nullable=False),
+        sa.Column("db_checksum", sa.String(), nullable=False),
+        sa.Column("file_version", sa.BigInteger(), nullable=True),
+        sa.Column("file_checksum", sa.String(), nullable=True),
+        sa.Column("file_write_status", sa.String(), nullable=False),
+        sa.Column("last_source", sa.String(), nullable=True),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("file_updated_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("last_materialization_error", sa.Text(), nullable=True),
+        sa.Column("last_materialization_attempt_at", sa.DateTime(timezone=True), nullable=True),
+        sa.CheckConstraint(
+            "file_write_status IN ("
+            "'pending', "
+            "'writing', "
+            "'synced', "
+            "'failed', "
+            "'external_change_detected'"
+            ")",
+            name="ck_note_content_file_write_status",
+        ),
+        sa.ForeignKeyConstraint(["entity_id"], ["entity.id"], ondelete="CASCADE"),
+        sa.ForeignKeyConstraint(["project_id"], ["project.id"], ondelete="CASCADE"),
+        sa.PrimaryKeyConstraint("entity_id"),
+    )
+    op.create_index("ix_note_content_project_id", "note_content", ["project_id"], unique=False)
+    op.create_index("ix_note_content_file_path", "note_content", ["file_path"], unique=False)
+    op.create_index("ix_note_content_external_id", "note_content", ["external_id"], unique=True)
+
+
+def downgrade() -> None:
+    """Drop note_content and its supporting indexes."""
+    op.drop_index("ix_note_content_external_id", table_name="note_content")
+    op.drop_index("ix_note_content_file_path", table_name="note_content")
+    op.drop_index("ix_note_content_project_id", table_name="note_content")
+    op.drop_table("note_content")

src/basic_memory/models/__init__.py

@@ -2,12 +2,13 @@
 
 import basic_memory
 from basic_memory.models.base import Base
-from basic_memory.models.knowledge import Entity, Observation, Relation
+from basic_memory.models.knowledge import Entity, NoteContent, Observation, Relation
 from basic_memory.models.project import Project
 
 __all__ = [
     "Base",
     "Entity",
+    "NoteContent",
     "Observation",
     "Relation",
     "Project",

src/basic_memory/models/knowledge.py

@@ -6,6 +6,8 @@
 from typing import Optional
 
 from sqlalchemy import (
+    BigInteger,
+    CheckConstraint,
     Integer,
     String,
     Text,
@@ -116,6 +118,12 @@ class Entity(Base):
         foreign_keys="[Relation.to_id]",
         cascade="all, delete-orphan",
     )
+    note_content = relationship(
+        "NoteContent",
+        back_populates="entity",
+        cascade="all, delete-orphan",
+        uselist=False,
+    )
 
     @property
     def relations(self):
@@ -141,6 +149,74 @@ def __repr__(self) -> str:
         return f"Entity(id={self.id}, external_id='{self.external_id}', name='{self.title}', type='{self.note_type}', checksum='{self.checksum}')"
 
 
+class NoteContent(Base):
+    """Materialized markdown content and sync state for a note entity."""
+
+    __tablename__ = "note_content"
+    __table_args__ = (
+        CheckConstraint(
+            "file_write_status IN ("
+            "'pending', "
+            "'writing', "
+            "'synced', "
+            "'failed', "
+            "'external_change_detected'"
+            ")",
+            name="ck_note_content_file_write_status",
+        ),
+        Index("ix_note_content_project_id", "project_id"),
+        Index("ix_note_content_file_path", "file_path"),
+        Index("ix_note_content_external_id", "external_id", unique=True),
+    )
+
+    # Core identity mirrored from entity for hot note reads
+    entity_id: Mapped[int] = mapped_column(
+        Integer,
+        ForeignKey("entity.id", ondelete="CASCADE"),
+        primary_key=True,
+    )
+    project_id: Mapped[int] = mapped_column(
+        Integer,
+        ForeignKey("project.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+    external_id: Mapped[str] = mapped_column(String, nullable=False)
+    file_path: Mapped[str] = mapped_column(String, nullable=False)
+
+    # Materialized content version tracked in the tenant database
+    markdown_content: Mapped[str] = mapped_column(Text, nullable=False)
+    db_version: Mapped[int] = mapped_column(BigInteger, nullable=False)
+    db_checksum: Mapped[str] = mapped_column(String, nullable=False)
+
+    # File materialization state tracked against the latest write attempts
+    file_version: Mapped[Optional[int]] = mapped_column(BigInteger, nullable=True)
+    file_checksum: Mapped[Optional[str]] = mapped_column(String, nullable=True)
+    file_write_status: Mapped[str] = mapped_column(String, nullable=False, default="pending")
+    last_source: Mapped[Optional[str]] = mapped_column(String, nullable=True)
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        default=lambda: datetime.now().astimezone(),
+        onupdate=lambda: datetime.now().astimezone(),
+    )
+    file_updated_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime(timezone=True),
+        nullable=True,
+    )
+    last_materialization_error: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
+    last_materialization_attempt_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime(timezone=True),
+        nullable=True,
+    )
+
+    entity = relationship("Entity", back_populates="note_content")
+
+    def __repr__(self) -> str:  # pragma: no cover
+        return (
+            f"NoteContent(entity_id={self.entity_id}, external_id='{self.external_id}', "
+            f"file_path='{self.file_path}', file_write_status='{self.file_write_status}')"
+        )
+
+
 class Observation(Base):
     """An observation about an entity.
 

src/basic_memory/repository/__init__.py

@@ -1,10 +1,12 @@
 from .entity_repository import EntityRepository
+from .note_content_repository import NoteContentRepository
 from .observation_repository import ObservationRepository
 from .project_repository import ProjectRepository
 from .relation_repository import RelationRepository
 
 __all__ = [
     "EntityRepository",
+    "NoteContentRepository",
     "ObservationRepository",
     "ProjectRepository",
     "RelationRepository",