diff --git a/app/assets_scanner.py b/app/assets_scanner.py
index 0f199719d..5ec1ebe88 100644
--- a/app/assets_scanner.py
+++ b/app/assets_scanner.py
@@ -31,11 +31,11 @@ from .database.helpers import (
 from .database.models import Asset, AssetCacheState, AssetInfo
 from .database.services import (
     compute_hash_and_dedup_for_cache_state,
-    ensure_seed_for_path,
     list_cache_states_by_asset_id,
     list_cache_states_with_asset_under_prefixes,
     list_unhashed_candidates_under_prefixes,
     list_verify_candidates_under_prefixes,
+    seed_from_path,
 )
 
 LOGGER = logging.getLogger(__name__)
@@ -147,7 +147,7 @@ async def sync_seed_assets(roots: list[schemas_in.RootType]) -> None:
             if tag_pool:
                 await ensure_tags_exist(sess, tag_pool, tag_type="user")
             for ap, sz, mt, name, tags in new_specs:
-                await ensure_seed_for_path(
+                await seed_from_path(
                     sess,
                     abs_path=ap,
                     size_bytes=sz,
diff --git a/app/database/services/__init__.py b/app/database/services/__init__.py
index 88e97bfb0..fae9eb670 100644
--- a/app/database/services/__init__.py
+++ b/app/database/services/__init__.py
@@ -1,12 +1,12 @@
 from .content import (
     check_fs_asset_exists_quick,
     compute_hash_and_dedup_for_cache_state,
-    ensure_seed_for_path,
     ingest_fs_asset,
     list_cache_states_with_asset_under_prefixes,
     list_unhashed_candidates_under_prefixes,
     list_verify_candidates_under_prefixes,
     redirect_all_references_then_delete_asset,
+    seed_from_path,
     touch_asset_infos_by_fs_path,
 )
 from .info import (
@@ -49,7 +49,7 @@ __all__ = [
     "get_asset_tags", "list_tags_with_usage", "set_asset_info_preview",
     "fetch_asset_info_and_asset", "fetch_asset_info_asset_and_tags",
     # content
-    "check_fs_asset_exists_quick", "ensure_seed_for_path",
+    "check_fs_asset_exists_quick", "seed_from_path",
     "redirect_all_references_then_delete_asset",
     "compute_hash_and_dedup_for_cache_state",
     "list_unhashed_candidates_under_prefixes", "list_verify_candidates_under_prefixes",
diff --git a/app/database/services/content.py b/app/database/services/content.py
index 298660129..84fa01f01 100644
--- a/app/database/services/content.py
+++ b/app/database/services/content.py
@@ -1,6 +1,7 @@
 import contextlib
 import logging
 import os
+import uuid
 from datetime import datetime
 from typing import Any, Optional, Sequence, Union
 
@@ -19,7 +20,7 @@ from ..helpers import (
     escape_like_prefix,
     remove_missing_tag_for_asset_id,
 )
-from ..models import Asset, AssetCacheState, AssetInfo, AssetInfoTag, Tag
+from ..models import Asset, AssetCacheState, AssetInfo, AssetInfoMeta, AssetInfoTag, Tag
 from ..timeutil import utcnow
 from .info import replace_asset_info_metadata_projection
 from .queries import list_cache_states_by_asset_id, pick_best_live_path
@@ -56,7 +57,7 @@ async def check_fs_asset_exists_quick(
     return row is not None
 
 
-async def ensure_seed_for_path(
+async def seed_from_path(
     session: AsyncSession,
     *,
     abs_path: str,
@@ -66,69 +67,131 @@ async def ensure_seed_for_path(
     tags: Sequence[str],
     owner_id: str = "",
     skip_tag_ensure: bool = False,
-) -> str:
-    """Ensure: Asset(hash=NULL), AssetCacheState(file_path), and AssetInfo exist for the path. Returns asset_id."""
+) -> None:
+    """Creates Asset(hash=NULL), AssetCacheState(file_path), and AssetInfo exist for the path."""
     locator = os.path.abspath(abs_path)
     now = utcnow()
+    dialect = session.bind.dialect.name
 
-    state = (
-        await session.execute(
-            sa.select(AssetCacheState, Asset)
-            .join(Asset, Asset.id == AssetCacheState.asset_id)
-            .where(AssetCacheState.file_path == locator)
-            .limit(1)
+    new_asset_id = str(uuid.uuid4())
+    new_info_id = str(uuid.uuid4())
+
+    # 1) Insert Asset (hash=NULL) – no conflict expected
+    asset_vals = {
+        "id": new_asset_id,
+        "hash": None,
+        "size_bytes": size_bytes,
+        "mime_type": None,
+        "created_at": now,
+    }
+    if dialect == "sqlite":
+        await session.execute(d_sqlite.insert(Asset).values(**asset_vals))
+    elif dialect == "postgresql":
+        await session.execute(d_pg.insert(Asset).values(**asset_vals))
+    else:
+        raise NotImplementedError(f"Unsupported database dialect: {dialect}")
+
+    # 2) Try to claim file_path in AssetCacheState. Our concurrency gate.
+    acs_vals = {
+        "asset_id": new_asset_id,
+        "file_path": locator,
+        "mtime_ns": mtime_ns,
+    }
+    if dialect == "sqlite":
+        ins_state = (
+            d_sqlite.insert(AssetCacheState)
+            .values(**acs_vals)
+            .on_conflict_do_nothing(index_elements=[AssetCacheState.file_path])
         )
-    ).first()
-    if state:
-        state_row: AssetCacheState = state[0]
-        asset_row: Asset = state[1]
-        changed = state_row.mtime_ns is None or int(state_row.mtime_ns) != mtime_ns
-        if changed:
-            state_row.mtime_ns = mtime_ns
-            state_row.needs_verify = True
-            if asset_row.size_bytes == 0 and size_bytes > 0:
-                asset_row.size_bytes = size_bytes
-            await session.flush()
-        return asset_row.id
+        state_inserted = int((await session.execute(ins_state)).rowcount or 0) > 0
+    else:
+        ins_state = (
+            d_pg.insert(AssetCacheState)
+            .values(**acs_vals)
+            .on_conflict_do_nothing(index_elements=[AssetCacheState.file_path])
+            .returning(AssetCacheState.id)
+        )
+        state_inserted = (await session.execute(ins_state)).scalar_one_or_none() is not None
 
-    asset = Asset(hash=None, size_bytes=size_bytes, mime_type=None, created_at=now)
-    session.add(asset)
-    await session.flush()  # to get id
+    if not state_inserted:
+        # Lost the race - clean up our orphan seed Asset and exit
+        with contextlib.suppress(Exception):
+            await session.execute(sa.delete(Asset).where(Asset.id == new_asset_id))
+        return
 
-    cs = AssetCacheState(asset_id=asset.id, file_path=locator, mtime_ns=mtime_ns, needs_verify=False)
-    session.add(cs)
+    # 3) Create AssetInfo (unique(asset_id, owner_id, name)).
+    fname = compute_relative_filename(locator)
 
-    info = AssetInfo(
-        owner_id=owner_id,
-        name=info_name,
-        asset_id=asset.id,
-        preview_id=None,
-        created_at=now,
-        updated_at=now,
-        last_access_time=now,
-    )
-    session.add(info)
-    await session.flush()
+    info_vals = {
+        "id": new_info_id,
+        "owner_id": owner_id,
+        "name": info_name,
+        "asset_id": new_asset_id,
+        "preview_id": None,
+        "user_metadata": {"filename": fname} if fname else None,
+        "created_at": now,
+        "updated_at": now,
+        "last_access_time": now,
+    }
+    if dialect == "sqlite":
+        ins_info = (
+            d_sqlite.insert(AssetInfo)
+            .values(**info_vals)
+            .on_conflict_do_nothing(index_elements=[AssetInfo.asset_id, AssetInfo.owner_id, AssetInfo.name])
+        )
+        info_inserted = int((await session.execute(ins_info)).rowcount or 0) > 0
+    else:
+        ins_info = (
+            d_pg.insert(AssetInfo)
+            .values(**info_vals)
+            .on_conflict_do_nothing(index_elements=[AssetInfo.asset_id, AssetInfo.owner_id, AssetInfo.name])
+            .returning(AssetInfo.id)
+        )
+        info_inserted = (await session.execute(ins_info)).scalar_one_or_none() is not None
 
-    with contextlib.suppress(Exception):
-        computed = compute_relative_filename(locator)
-        if computed:
-            await replace_asset_info_metadata_projection(
-                session,
-                asset_info_id=info.id,
-                user_metadata={"filename": computed},
-            )
+    # 4) If we actually inserted AssetInfo, attach tags and filename.
+    if info_inserted:
+        want = normalize_tags(tags)
+        if want:
+            if not skip_tag_ensure:
+                await ensure_tags_exist(session, want, tag_type="user")
+            tag_rows = [
+                {
+                    "asset_info_id": new_info_id,
+                    "tag_name": t,
+                    "origin": "automatic",
+                    "added_at": now,
+                }
+                for t in want
+            ]
+            if dialect == "sqlite":
+                ins_links = (
+                    d_sqlite.insert(AssetInfoTag)
+                    .values(tag_rows)
+                    .on_conflict_do_nothing(index_elements=[AssetInfoTag.asset_info_id, AssetInfoTag.tag_name])
+                )
+            else:
+                ins_links = (
+                    d_pg.insert(AssetInfoTag)
+                    .values(tag_rows)
+                    .on_conflict_do_nothing(index_elements=[AssetInfoTag.asset_info_id, AssetInfoTag.tag_name])
+                )
+            await session.execute(ins_links)
 
-    want = normalize_tags(tags)
-    if want:
-        if not skip_tag_ensure:
-            await ensure_tags_exist(session, want, tag_type="user")
-        session.add_all([
-            AssetInfoTag(asset_info_id=info.id, tag_name=t, origin="automatic", added_at=now)
-            for t in want
-        ])
-    await session.flush()
-    return asset.id
+        if fname:  # simple filename projection with single row
+            meta_row = {
+                "asset_info_id": new_info_id,
+                "key": "filename",
+                "ordinal": 0,
+                "val_str": fname,
+                "val_num": None,
+                "val_bool": None,
+                "val_json": None,
+            }
+            if dialect == "sqlite":
+                await session.execute(d_sqlite.insert(AssetInfoMeta).values(**meta_row))
+            else:
+                await session.execute(d_pg.insert(AssetInfoMeta).values(**meta_row))
 
 
 async def redirect_all_references_then_delete_asset(