diff --git a/atests/test_retry_mechanisms.robot b/atests/test_retry_mechanisms.robot
index 342c8c7..34dbf4b 100644
--- a/atests/test_retry_mechanisms.robot
+++ b/atests/test_retry_mechanisms.robot
@@ -19,9 +19,9 @@ Test Global Retry Configuration
     ${config}=    Get Retry Configuration
     Should Be Equal As Integers    ${config}[max_retries]    5
     Should Be Equal As Numbers     ${config}[backoff_factor]    0.5
-    Should Contain    ${config}[retry_on_status]    500
-    Should Contain    ${config}[retry_on_status]    502
-    Should Contain    ${config}[retry_on_status]    503
+    List Should Contain Value    ${config}[retry_on_status]    ${500}
+    List Should Contain Value    ${config}[retry_on_status]    ${502}
+    List Should Contain Value    ${config}[retry_on_status]    ${503}
 
 Test Session Retry Configuration
     [Documentation]    Test setting session-specific retry configuration
diff --git a/src/HttpxLibrary/RetryKeywords.py b/src/HttpxLibrary/RetryKeywords.py
index df8a1da..379a64e 100644
--- a/src/HttpxLibrary/RetryKeywords.py
+++ b/src/HttpxLibrary/RetryKeywords.py
@@ -70,6 +70,12 @@ def set_global_retry_configuration(self,
         | Set Global Retry Configuration | max_retries=5 | backoff_factor=0.5 |
         | Set Global Retry Configuration | retry_on_status=500,502,503 | jitter=False |
         """
+        # Convert parameters to correct types (Robot Framework passes everything as strings)
+        max_retries = int(max_retries)
+        backoff_factor = float(backoff_factor)
+        backoff_max = float(backoff_max)
+        jitter = bool(jitter) if isinstance(jitter, bool) else str(jitter).lower() in ('true', '1', 'yes')
+        
         if isinstance(retry_on_status, str):
             retry_on_status = [int(code.strip()) for code in retry_on_status.split(',')]
         
@@ -107,6 +113,12 @@ def set_session_retry_configuration(self,
         | Set Session Retry Configuration | my_session | max_retries=5 |
         | Set Session Retry Configuration | api_session | retry_on_status=429,503 | backoff_factor=1.0 |
         """
+        # Convert parameters to correct types (Robot Framework passes everything as strings)
+        max_retries = int(max_retries)
+        backoff_factor = float(backoff_factor)
+        backoff_max = float(backoff_max)
+        jitter = bool(jitter) if isinstance(jitter, bool) else str(jitter).lower() in ('true', '1', 'yes')
+        
         if isinstance(retry_on_status, str):
             retry_on_status = [int(code.strip()) for code in retry_on_status.split(',')]
         
@@ -275,13 +287,22 @@ def retry_request_on_session(self,
         """
         session = self._cache.switch(alias)
         
-        # Get base retry config and override if specified
-        retry_config = self._get_retry_config(alias)
+        # Get base retry config and create a copy to avoid modifying the original
+        base_config = self._get_retry_config(alias)
+        retry_config = RetryConfig(
+            max_retries=base_config.max_retries,
+            backoff_factor=base_config.backoff_factor,
+            backoff_max=base_config.backoff_max,
+            retry_on_status=base_config.retry_on_status.copy(),
+            retry_on_exceptions=base_config.retry_on_exceptions.copy(),
+            jitter=base_config.jitter
+        )
         
+        # Override with request-specific parameters (convert types as needed)
         if max_retries is not None:
-            retry_config.max_retries = max_retries
+            retry_config.max_retries = int(max_retries)
         if backoff_factor is not None:
-            retry_config.backoff_factor = backoff_factor
+            retry_config.backoff_factor = float(backoff_factor)
         if retry_on_status is not None:
             if isinstance(retry_on_status, str):
                 retry_config.retry_on_status = [int(code.strip()) for code in retry_on_status.split(',')]
@@ -333,6 +354,12 @@ def wait_until_request_succeeds(self,
         | ${response}= | Wait Until Request Succeeds | my_session | GET | /health |
         | ${response}= | Wait Until Request Succeeds | my_session | GET | /api/ready | timeout=120 | interval=5 |
         """
+        # Convert parameters to correct types (Robot Framework passes everything as strings)
+        timeout = float(timeout)
+        interval = float(interval)
+        if isinstance(expected_status, str) and expected_status.isdigit():
+            expected_status = int(expected_status)
+        
         session = self._cache.switch(alias)
         method_func = getattr(session, method.lower())
         
diff --git a/src/HttpxLibrary/SessionKeywords.py b/src/HttpxLibrary/SessionKeywords.py
index 2ed6bad..fb84e40 100644
--- a/src/HttpxLibrary/SessionKeywords.py
+++ b/src/HttpxLibrary/SessionKeywords.py
@@ -773,10 +773,11 @@ def _get_url(session, uri):
         """
         Helper method to get the full url
         """
-        url = session.url
+        url = str(session.url)  # Ensure url is string
         if uri:
+            uri = str(uri)  # Ensure uri is string
             slash = '' if uri.startswith('/') else '/'
-            url = "%s%s%s" % (session.url, slash, uri)
+            url = "%s%s%s" % (url, slash, uri)
         return url
 
     # FIXME might be broken we need a test for this