diff --git a/core/pyproject.toml b/core/pyproject.toml
index e9214da..c5c8f07 100644
--- a/core/pyproject.toml
+++ b/core/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "utcp"
-version = "1.1.1"
+version = "1.1.2"
 authors = [
   { name = "UTCP Contributors" },
 ]
diff --git a/core/src/utcp/implementations/default_variable_substitutor.py b/core/src/utcp/implementations/default_variable_substitutor.py
index ccc6dfb..b197d0b 100644
--- a/core/src/utcp/implementations/default_variable_substitutor.py
+++ b/core/src/utcp/implementations/default_variable_substitutor.py
@@ -100,8 +100,8 @@ def substitute(self, obj: dict | list | str, config: UtcpClientConfig, variable_
             raise ValueError(f"Variable namespace '{variable_namespace}' contains invalid characters. Only alphanumeric characters and underscores are allowed.")
         
         if isinstance(obj, str):
-            # Skip substitution for JSON $ref strings
-            if '$ref' in obj:
+            # Skip substitution for JSON Schema $ref (but not variables like $refresh_token)
+            if re.search(r'\$ref(?![a-zA-Z0-9_])', obj):
                 return obj
 
             # Use a regular expression to find all variables in the string, supporting ${VAR} and $VAR formats
@@ -168,9 +168,10 @@ def find_required_variables(self, obj: dict | list | str, variable_namespace: Op
                 result.extend(vars)
             return result
         elif isinstance(obj, str):
-            # Skip substitution for JSON $ref strings
-            if '$ref' in obj:
+            # Skip JSON Schema $ref (but not variables like $refresh_token)
+            if re.search(r'\$ref(?![a-zA-Z0-9_])', obj):
                 return []
+
             # Find all variables in the string, supporting ${VAR} and $VAR formats
             variables = []
             pattern = r'\${([a-zA-Z0-9_]+)}|\$([a-zA-Z0-9_]+)'
diff --git a/plugins/communication_protocols/http/pyproject.toml b/plugins/communication_protocols/http/pyproject.toml
index ae759ed..0ce7a83 100644
--- a/plugins/communication_protocols/http/pyproject.toml
+++ b/plugins/communication_protocols/http/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "utcp-http"
-version = "1.1.0"
+version = "1.1.1"
 authors = [
   { name = "UTCP Contributors" },
 ]
diff --git a/plugins/communication_protocols/http/src/utcp_http/openapi_converter.py b/plugins/communication_protocols/http/src/utcp_http/openapi_converter.py
index c16412a..824df2a 100644
--- a/plugins/communication_protocols/http/src/utcp_http/openapi_converter.py
+++ b/plugins/communication_protocols/http/src/utcp_http/openapi_converter.py
@@ -83,11 +83,12 @@ class OpenApiConverter:
     Attributes:
         spec: The parsed OpenAPI specification dictionary.
         spec_url: Optional URL where the specification was retrieved from.
+        base_url: Optional base URL override for all API endpoints.
         placeholder_counter: Counter for generating unique placeholder variables.
         call_template_name: Normalized name for the call_template derived from the spec.
     """
 
-    def __init__(self, openapi_spec: Dict[str, Any], spec_url: Optional[str] = None, call_template_name: Optional[str] = None, auth_tools: Optional[Auth] = None):
+    def __init__(self, openapi_spec: Dict[str, Any], spec_url: Optional[str] = None, call_template_name: Optional[str] = None, auth_tools: Optional[Auth] = None, base_url: Optional[str] = None):
         """Initializes the OpenAPI converter.
 
         Args:
@@ -98,10 +99,13 @@ def __init__(self, openapi_spec: Dict[str, Any], spec_url: Optional[str] = None,
                 the specification title is not provided.
             auth_tools: Optional auth configuration for generated tools.
                 Applied only to endpoints that require authentication per OpenAPI spec.
+            base_url: Optional base URL override for all API endpoints.
+                When provided, this takes precedence over servers in the spec.
         """
         self.spec = openapi_spec
         self.spec_url = spec_url
         self.auth_tools = auth_tools
+        self._base_url_override = base_url
         # Single counter for all placeholder variables
         self.placeholder_counter = 0
         if call_template_name is None:
@@ -141,9 +145,12 @@ def convert(self) -> UtcpManual:
         """
         self.placeholder_counter = 0
         tools = []
-        servers = self.spec.get("servers")
-        if servers:
-            base_url = servers[0].get("url", "/")
+        
+        # Determine base URL: override > servers > spec_url > fallback
+        if self._base_url_override:
+            base_url = self._base_url_override
+        elif self.spec.get("servers"):
+            base_url = self.spec["servers"][0].get("url", "/")
         elif self.spec_url:
             parsed_url = urlparse(self.spec_url)
             base_url = f"{parsed_url.scheme}://{parsed_url.netloc}"