diff --git a/sqlite_utils/cli.py b/sqlite_utils/cli.py
index 136411a..7d59e53 100644
--- a/sqlite_utils/cli.py
+++ b/sqlite_utils/cli.py
@@ -393,7 +393,7 @@ def analyze(path, names):
         else:
             db.analyze()
     except OperationalError as e:
-        raise click.ClickException(e)
+        raise click.ClickException(str(e))
 
 
 @cli.command()
@@ -536,7 +536,7 @@ def add_foreign_key(
     try:
         db[table].add_foreign_key(column, other_table, other_column, ignore=ignore)
     except AlterError as e:
-        raise click.ClickException(e)
+        raise click.ClickException(str(e))
 
 
 @cli.command(name="add-foreign-keys")
@@ -571,7 +571,7 @@ def add_foreign_keys(path, foreign_key, load_extension):
     try:
         db.add_foreign_keys(tuples)
     except AlterError as e:
-        raise click.ClickException(e)
+        raise click.ClickException(str(e))
 
 
 @cli.command(name="index-foreign-keys")
@@ -3361,7 +3361,10 @@ def _load_extensions(db, load_extension):
         db.conn.enable_load_extension(True)
         for ext in load_extension:
             if ext == "spatialite" and not os.path.exists(ext):
-                ext = find_spatialite()
+                found = find_spatialite()
+                if found is None:
+                    raise click.ClickException("Could not find SpatiaLite extension")
+                ext = found
             if ":" in ext:
                 path, _, entrypoint = ext.partition(":")
                 db.conn.execute("SELECT load_extension(?, ?)", [path, entrypoint])
diff --git a/sqlite_utils/db.py b/sqlite_utils/db.py
index f6fe5ed..049adda 100644
--- a/sqlite_utils/db.py
+++ b/sqlite_utils/db.py
@@ -328,6 +328,7 @@ class Database:
 
     _counts_table_name = "_counts"
     use_counts_table = False
+    conn: sqlite3.Connection
 
     def __init__(
         self,