fix: resolve get_database_schema resource validation errors

Dockerfile

@@ -22,7 +22,7 @@ RUN --mount=type=cache,target=/root/.cache/uv \
   uv sync --frozen --no-dev
 
 
-FROM python:3.13-slim-bookworm
+FROM python:3.12-slim-bookworm
 # It is important to use the image that matches the builder, as the path to the
 # Python executable must be the same, e.g., using `python:3.11-slim-bookworm`
 # will fail.

src/postgres_mcp/resources/database_resources.py

@@ -35,13 +35,16 @@ async def get_database_schema() -> str:  # pyright: ignore[reportUnusedFunction]
             sql_driver: Any = await get_sql_driver_func()
 
             # Query information_schema for tables
+            # Use pg_class directly to avoid ::regclass issues with views
             tables_query = """
                 SELECT
                     t.table_schema,
                     t.table_name,
                     t.table_type,
-                    obj_description((t.table_schema||'.'||t.table_name)::regclass) as table_comment
+                    obj_description(c.oid, 'pg_class') as table_comment
                 FROM information_schema.tables t
+                LEFT JOIN pg_namespace n ON n.nspname = t.table_schema
+                LEFT JOIN pg_class c ON c.relnamespace = n.oid AND c.relname = t.table_name
                 WHERE t.table_schema NOT IN ('pg_catalog', 'information_schema')
                 ORDER BY t.table_schema, t.table_name
             """

src/postgres_mcp/sql/safe_sql.py

@@ -306,6 +306,9 @@ class SafeSqlDriver(SqlDriver):
         "unicode_version",
         "icu_unicode_version",
         # Database object information functions
+        "obj_description",
+        "col_description",
+        "shobj_description",
         "pg_column_size",
         "pg_column_compression",
         "pg_column_toast_chunk_id",