diff --git a/fpaste b/fpaste
index f3e1ab2..29055a8 100755
--- a/fpaste
+++ b/fpaste
@@ -148,7 +148,8 @@ def request(
 def parse_error(body: bytes, default: str = "request failed") -> str:
     """Parse error message from JSON response body."""
     try:
-        return json.loads(body).get("error", default)
+        result = json.loads(body).get("error", default)
+        return str(result) if result is not None else default
     except (json.JSONDecodeError, UnicodeDecodeError):
         return default
 
@@ -1310,7 +1311,10 @@ def cmd_register(args: argparse.Namespace, config: dict[str, Any]) -> None:
 
         cn = certificate.subject.get_attributes_for_oid(NameOID.COMMON_NAME)
         if cn:
-            print(f"common name: {cn[0].value}", file=sys.stderr)
+            cn_value = cn[0].value
+            if isinstance(cn_value, bytes):
+                cn_value = cn_value.decode("utf-8", errors="replace")
+            print(f"common name: {cn_value}", file=sys.stderr)
 
     print(f"fingerprint: {fingerprint}", file=sys.stderr)
 
@@ -1345,6 +1349,7 @@ def cmd_cert(args: argparse.Namespace, config: dict[str, Any]) -> None:
             die(f"cert file exists: {cert_file} (use --force)")
 
     # Generate private key
+    private_key: rsa.RSAPrivateKey | ec.EllipticCurvePrivateKey
     if args.algorithm == "rsa":
         key_size = args.bits or 4096
         print(f"generating {key_size}-bit RSA key...", file=sys.stderr)
diff --git a/tests/test_container_integration.py b/tests/test_container_integration.py
index d5b9116..ffb19f1 100644
--- a/tests/test_container_integration.py
+++ b/tests/test_container_integration.py
@@ -18,6 +18,7 @@ import os
 import shutil
 import subprocess
 import time
+from typing import Any
 
 import pytest
 
@@ -25,10 +26,9 @@ import pytest
 # This allows the file to be collected without requiring 'requests'
 _INTEGRATION_ENABLED = bool(os.environ.get("FLASKPASTE_INTEGRATION"))
 
+requests: Any = None
 if _INTEGRATION_ENABLED:
-    import requests
-else:
-    requests = None  # type: ignore[assignment]
+    import requests  # type: ignore[import-untyped,no-redef]
 
 # Configuration
 CONTAINER_NAME = "flaskpaste-test"
diff --git a/tests/test_paste_management.py b/tests/test_paste_management.py
index 99405db..faa7a9b 100644
--- a/tests/test_paste_management.py
+++ b/tests/test_paste_management.py
@@ -95,7 +95,9 @@ def create_paste(
 
     response = client.post("/", data=content, headers=headers)
     assert response.status_code == 201
-    return response.get_json()["id"]
+    data = response.get_json()
+    assert data is not None
+    return str(data["id"])
 
 
 # ─────────────────────────────────────────────────────────────────────────────