diff --git a/src/repositories/welcome_template.py b/src/repositories/welcome_template.py
new file mode 100644
index 0000000..a3f40f0
--- /dev/null
+++ b/src/repositories/welcome_template.py
@@ -0,0 +1,53 @@
+"""Repository for the per-instance welcome-prompt override (singleton row)."""
+
+from datetime import datetime, timezone
+from typing import Any, Optional
+
+import duckdb
+
+
+class WelcomeTemplateRepository:
+    def __init__(self, conn: duckdb.DuckDBPyConnection):
+        self.conn = conn
+
+    def get(self) -> dict[str, Any]:
+        """Return the singleton row. Always exists post-migration; content
+        is None when no override is set (= use shipped default)."""
+        row = self.conn.execute(
+            "SELECT id, content, updated_at, updated_by FROM welcome_template WHERE id = 1"
+        ).fetchone()
+        if row is None:
+            # Defensive: re-seed if a previous admin manually deleted it.
+            self.conn.execute(
+                "INSERT INTO welcome_template (id, content) VALUES (1, NULL) "
+                "ON CONFLICT (id) DO NOTHING"
+            )
+            return {"id": 1, "content": None, "updated_at": None, "updated_by": None}
+        return {
+            "id": row[0],
+            "content": row[1],
+            "updated_at": row[2],
+            "updated_by": row[3],
+        }
+
+    def set(self, content: str, *, updated_by: str) -> None:
+        now = datetime.now(timezone.utc)
+        self.conn.execute(
+            """INSERT INTO welcome_template (id, content, updated_at, updated_by)
+               VALUES (1, ?, ?, ?)
+               ON CONFLICT (id) DO UPDATE SET
+                   content = excluded.content,
+                   updated_at = excluded.updated_at,
+                   updated_by = excluded.updated_by""",
+            [content, now, updated_by],
+        )
+
+    def reset(self, *, updated_by: str) -> None:
+        """Clear override; renderer falls back to shipped default."""
+        now = datetime.now(timezone.utc)
+        self.conn.execute(
+            """UPDATE welcome_template
+               SET content = NULL, updated_at = ?, updated_by = ?
+               WHERE id = 1""",
+            [now, updated_by],
+        )
diff --git a/tests/test_welcome_template_repo.py b/tests/test_welcome_template_repo.py
new file mode 100644
index 0000000..89d41c7
--- /dev/null
+++ b/tests/test_welcome_template_repo.py
@@ -0,0 +1,40 @@
+"""Unit tests for WelcomeTemplateRepository."""
+
+import duckdb
+import pytest
+
+from src.db import _ensure_schema
+from src.repositories.welcome_template import WelcomeTemplateRepository
+
+
+@pytest.fixture
+def conn(tmp_path):
+    db_path = tmp_path / "system.duckdb"
+    c = duckdb.connect(str(db_path))
+    _ensure_schema(c)
+    yield c
+    c.close()
+
+
+def test_get_returns_none_on_fresh_install(conn):
+    repo = WelcomeTemplateRepository(conn)
+    row = repo.get()
+    assert row is not None
+    assert row["content"] is None  # default sentinel
+
+
+def test_set_stores_content(conn):
+    repo = WelcomeTemplateRepository(conn)
+    repo.set("Hello {{ instance.name }}", updated_by="admin@example.com")
+    row = repo.get()
+    assert row["content"] == "Hello {{ instance.name }}"
+    assert row["updated_by"] == "admin@example.com"
+    assert row["updated_at"] is not None
+
+
+def test_reset_clears_content(conn):
+    repo = WelcomeTemplateRepository(conn)
+    repo.set("custom", updated_by="admin@example.com")
+    repo.reset(updated_by="admin@example.com")
+    row = repo.get()
+    assert row["content"] is None