diff --git a/alembic/versions/0035_comm_search_index.py b/alembic/versions/0035_comm_search_index.py
new file mode 100644
index 0000000..424b6dc
--- /dev/null
+++ b/alembic/versions/0035_comm_search_index.py
@@ -0,0 +1,51 @@
+"""Add search_tsv and embedding columns to comm_messages for full-text search indexing.
+
+Revision ID: 0035
+Revises: 0034_automation_config
+Create Date: 2026-07-25
+"""
+
+from __future__ import annotations
+
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import TSVECTOR
+
+revision: str = "0035_comm_search_index"
+down_revision: Union[str, None] = "0034_automation_config"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Add search_tsv column for full-text search
+    op.add_column(
+        "comm_messages",
+        sa.Column("search_tsv", TSVECTOR, nullable=True),
+    )
+    # Add embedding column for vector search (768 dimensions matching pgvector)
+    op.execute(
+        "ALTER TABLE comm_messages ADD COLUMN embedding vector(768)"
+    )
+    # Create GIN index on search_tsv for fast FTS queries
+    op.create_index(
+        "ix_comm_messages_search_tsv",
+        "comm_messages",
+        ["search_tsv"],
+        postgresql_using="gin",
+    )
+    # Create IVFFlat index on embedding for fast vector search
+    op.execute(
+        "CREATE INDEX IF NOT EXISTS ix_comm_messages_embedding "
+        "ON comm_messages USING ivfflat (embedding vector_cosine_ops) "
+        "WITH (lists = 100)"
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("ix_comm_messages_embedding", table_name="comm_messages")
+    op.drop_index("ix_comm_messages_search_tsv", table_name="comm_messages")
+    op.drop_column("comm_messages", "embedding")
+    op.drop_column("comm_messages", "search_tsv")
diff --git a/app/plugins/builtins/dms/routes.py b/app/plugins/builtins/dms/routes.py
index 1b076cc..1f7eeb5 100644
--- a/app/plugins/builtins/dms/routes.py
+++ b/app/plugins/builtins/dms/routes.py
@@ -878,7 +878,7 @@ async def share_file(
             perm = Permission(
                 tenant_id=tenant_id,
                 file_id=fid,
-                user_id=uuid.uuid4(),  # placeholder user_id for group shares
+                user_id=uuid.UUID(current_user["user_id"]),
                 group_id=gid,
                 access_level=body.access_level,
             )
diff --git a/app/plugins/builtins/kommunikation/search_provider.py b/app/plugins/builtins/kommunikation/search_provider.py
index 1b59563..ab661e7 100644
--- a/app/plugins/builtins/kommunikation/search_provider.py
+++ b/app/plugins/builtins/kommunikation/search_provider.py
@@ -1,4 +1,4 @@
-"""Search provider for unified_search integration."""
+"""Search provider for unified_search integration — FTS + vector search for messages."""
 
 from __future__ import annotations
 
@@ -6,7 +6,7 @@ import logging
 import uuid
 from typing import Any
 
-from sqlalchemy import select, func, or_
+from sqlalchemy import select, func, or_, text as sql_text
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.plugins.builtins.kommunikation.models import (
@@ -14,6 +14,7 @@ from app.plugins.builtins.kommunikation.models import (
     CommMessage,
     CommParticipant,
 )
+from app.plugins.builtins.unified_search.embedding import generate_embedding
 
 logger = logging.getLogger(__name__)
 
@@ -21,6 +22,8 @@ logger = logging.getLogger(__name__)
 class CommSearchProvider:
     """Provider for unified_search — searches conversations and messages."""
 
+    entity_type = "message"
+
     async def search(
         self,
         db: AsyncSession,
@@ -103,10 +106,204 @@ class CommSearchProvider:
 
         return results
 
+    async def search_fts(
+        self,
+        db: AsyncSession,
+        tsquery: str,
+        tenant_id: uuid.UUID,
+        limit: int,
+    ) -> list[dict[str, Any]]:
+        """Full-text search on comm_messages.search_tsv."""
+        sql = sql_text(
+            """
+            SELECT m.*, ts_rank(m.search_tsv, to_tsquery('pg_catalog.german', :q)) AS rank
+            FROM comm_messages m
+            WHERE m.tenant_id = :tid
+              AND m.deleted_at IS NULL
+              AND m.search_tsv @@ to_tsquery('pg_catalog.german', :q)
+            ORDER BY rank DESC
+            LIMIT :lim
+            """
+        )
+        result = await db.execute(
+            sql,
+            {"q": tsquery, "tid": tenant_id, "lim": limit},
+        )
+        rows = result.mappings().all()
+        return [dict(r) for r in rows]
+
+    async def search_vector(
+        self,
+        db: AsyncSession,
+        embedding: list[float],
+        tenant_id: uuid.UUID,
+        limit: int,
+    ) -> list[dict[str, Any]]:
+        """Semantic vector search on comm_messages.embedding."""
+        sql = sql_text(
+            """
+            SELECT m.*, 1 - (m.embedding <=> cast(:emb AS vector)) AS score
+            FROM comm_messages m
+            WHERE m.tenant_id = :tid
+              AND m.deleted_at IS NULL
+              AND m.embedding IS NOT NULL
+            ORDER BY m.embedding <=> cast(:emb AS vector)
+            LIMIT :lim
+            """
+        )
+        result = await db.execute(
+            sql,
+            {"emb": str(embedding), "tid": tenant_id, "lim": limit},
+        )
+        rows = result.mappings().all()
+        return [dict(r) for r in rows]
+
+    async def get_embedding_text(
+        self,
+        db: AsyncSession,
+        entity_id: uuid.UUID,
+        tenant_id: uuid.UUID,
+    ) -> str:
+        """Get message content for embedding generation."""
+        sql = sql_text(
+            """
+            SELECT content FROM comm_messages
+            WHERE id = :eid AND tenant_id = :tid AND deleted_at IS NULL
+            """
+        )
+        result = await db.execute(sql, {"eid": entity_id, "tid": tenant_id})
+        row = result.mappings().first()
+        if row is None:
+            return ""
+        return row["content"] or ""
+
+    def to_search_result(self, entity: object) -> dict:
+        """Convert a comm_messages row to a search result dict."""
+        row = dict(entity) if isinstance(entity, dict) else {}
+        return {
+            "type": "message",
+            "id": str(row.get("id", "")),
+            "conversation_id": str(row.get("conversation_id", "")),
+            "content": row.get("content", ""),
+            "sender_type": row.get("sender_type", ""),
+            "created_at": str(row.get("created_at", "")) if row.get("created_at") else None,
+        }
+
     async def index_message(self, message: dict[str, Any]) -> None:
-        """Index a message for search (placeholder for future full-text indexing)."""
-        pass
+        """Index a single message for search — updates search_tsv and embedding.
+
+        Called after a message is created or updated. The message dict must contain
+        at least: id, tenant_id, content.
+        """
+        from app.core.db import async_session_factory
+
+        msg_id = message.get("id")
+        tenant_id = message.get("tenant_id")
+        content = message.get("content", "")
+
+        if not msg_id or not tenant_id:
+            logger.warning("index_message: missing id or tenant_id")
+            return
+
+        async with async_session_factory() as db:
+            try:
+                # Update search_tsv using PostgreSQL to_tsvector
+                sql_update_tsv = sql_text(
+                    """
+                    UPDATE comm_messages
+                    SET search_tsv = to_tsvector('pg_catalog.german', :content)
+                    WHERE id = :mid AND tenant_id = :tid
+                    """
+                )
+                await db.execute(
+                    sql_update_tsv,
+                    {"content": content, "mid": msg_id, "tid": tenant_id},
+                )
+
+                # Generate and store embedding
+                if content.strip():
+                    embedding = await generate_embedding(
+                        content, db=db, tenant_id=tenant_id
+                    )
+                    if embedding:
+                        sql_update_emb = sql_text(
+                            """
+                            UPDATE comm_messages
+                            SET embedding = cast(:emb AS vector)
+                            WHERE id = :mid AND tenant_id = :tid
+                            """
+                        )
+                        await db.execute(
+                            sql_update_emb,
+                            {"emb": str(embedding), "mid": msg_id, "tid": tenant_id},
+                        )
+
+                await db.commit()
+            except Exception:
+                await db.rollback()
+                logger.exception("Failed to index message %s", msg_id)
 
     async def reindex_all(self, db: AsyncSession, tenant_id: uuid.UUID) -> None:
-        """Full reindex (placeholder for future full-text indexing)."""
-        pass
+        """Full reindex of all messages for a tenant.
+
+        Iterates over all non-deleted messages and updates search_tsv and embedding.
+        """
+        sql_select = sql_text(
+            """
+            SELECT id, content FROM comm_messages
+            WHERE tenant_id = :tid AND deleted_at IS NULL
+            ORDER BY created_at ASC
+            """
+        )
+        result = await db.execute(sql_select, {"tid": tenant_id})
+        rows = result.mappings().all()
+
+        total = len(rows)
+        logger.info("Reindexing %d messages for tenant %s", total, tenant_id)
+
+        for i, row in enumerate(rows):
+            msg_id = row["id"]
+            content = row["content"] or ""
+
+            try:
+                # Update search_tsv
+                sql_update_tsv = sql_text(
+                    """
+                    UPDATE comm_messages
+                    SET search_tsv = to_tsvector('pg_catalog.german', :content)
+                    WHERE id = :mid AND tenant_id = :tid
+                    """
+                )
+                await db.execute(
+                    sql_update_tsv,
+                    {"content": content, "mid": msg_id, "tid": tenant_id},
+                )
+
+                # Generate and store embedding
+                if content.strip():
+                    embedding = await generate_embedding(
+                        content, db=db, tenant_id=tenant_id
+                    )
+                    if embedding:
+                        sql_update_emb = sql_text(
+                            """
+                            UPDATE comm_messages
+                            SET embedding = cast(:emb AS vector)
+                            WHERE id = :mid AND tenant_id = :tid
+                            """
+                        )
+                        await db.execute(
+                            sql_update_emb,
+                            {"emb": str(embedding), "mid": msg_id, "tid": tenant_id},
+                        )
+
+                if (i + 1) % 50 == 0:
+                    await db.commit()
+                    logger.debug("Reindexed %d/%d messages", i + 1, total)
+
+            except Exception:
+                logger.exception("Failed to reindex message %s", msg_id)
+                continue
+
+        await db.commit()
+        logger.info("Reindexing complete for tenant %s: %d messages", tenant_id, total)