diff --git a/imixs-ai-workflow/src/main/java/org/imixs/ai/workflow/OpenAIAPIAdapter.java b/imixs-ai-workflow/src/main/java/org/imixs/ai/workflow/OpenAIAPIAdapter.java
index 51b4f88..761a0b3 100644
--- a/imixs-ai-workflow/src/main/java/org/imixs/ai/workflow/OpenAIAPIAdapter.java
+++ b/imixs-ai-workflow/src/main/java/org/imixs/ai/workflow/OpenAIAPIAdapter.java
@@ -109,12 +109,13 @@ public class OpenAIAPIAdapter implements SignalAdapter {
     private static Logger logger = Logger.getLogger(OpenAIAPIAdapter.class.getName());
 
     @Inject
-    @ConfigProperty(name = OpenAIAPIService.LLM_SERVICE_ENDPOINT)
-    Optional<String> mlDefaultAPIEndpoint;
+    @ConfigProperty(name = OpenAIAPIService.ENV_LLM_SERVICE_ENDPOINT)
+    Optional<String> serviceEndpoint;
 
-    @Inject
-    @ConfigProperty(name = OpenAIAPIService.LLM_MODEL, defaultValue = "imixs-model")
-    String mlDefaultModel;
+    // @Inject
+    // @ConfigProperty(name = OpenAIAPIService.LLM_MODEL, defaultValue =
+    // "imixs-model")
+    // String mlDefaultModel;
 
     @Inject
     private WorkflowService workflowService;
@@ -202,7 +203,7 @@ public ItemCollection execute(ItemCollection workitem, ItemCollection event)
                         // postPromptCompletion
                         JsonObject jsonPrompt = llmService.buildJsonPromptObject(llmPrompt,
                                 workitem.getItemValueString("ai.prompt.prompt_options"));
-                        String completionResult = llmService.postPromptCompletion(llmAPIEndpoint, jsonPrompt);
+                        String completionResult = llmService.postPromptCompletion(jsonPrompt, llmAPIEndpoint);
                         // process the ai.result....
                         if (llmAPIDebug) {
                             logger.info("===> Completion Result: ");
@@ -276,7 +277,10 @@ private String readPromptTemplate(ItemCollection event) {
 
     /**
      * This helper method parses the ml api endpoint either provided by a model
-     * definition or a imixs.property or an environment variable
+     * definition or a imixs.property or an environment variable.
+     * <p>
+     * If not api endpoint is defined by the model the adapter uses the default api
+     * endpoint.
      * 
      * @param llmPrompt
      * @return
@@ -286,8 +290,7 @@ private String parseLLMEndpointByBPMN(ItemCollection llmPrompt) throws PluginExc
         boolean debug = logger.isLoggable(Level.FINE);
         String llmAPIEndpoint = null;
 
-        // test if the model provides a MLEndpoint. If not, the adapter uses the
-        // mlDefaultAPIEndpoint
+        // Test if the model provides a API Endpoint.
         llmAPIEndpoint = null;
         if (llmPrompt != null) {
             llmAPIEndpoint = llmPrompt.getItemValueString("endpoint");
@@ -296,8 +299,8 @@ private String parseLLMEndpointByBPMN(ItemCollection llmPrompt) throws PluginExc
         // switch to default api endpoint?
         if (llmAPIEndpoint == null || llmAPIEndpoint.isEmpty()) {
             // set defautl api endpoint if defined
-            if (mlDefaultAPIEndpoint.isPresent() && !mlDefaultAPIEndpoint.get().isEmpty()) {
-                llmAPIEndpoint = mlDefaultAPIEndpoint.get();
+            if (serviceEndpoint.isPresent() && !serviceEndpoint.get().isEmpty()) {
+                llmAPIEndpoint = serviceEndpoint.get();
             }
         }
         if (debug) {
diff --git a/imixs-ai-workflow/src/main/java/org/imixs/ai/workflow/OpenAIAPIService.java b/imixs-ai-workflow/src/main/java/org/imixs/ai/workflow/OpenAIAPIService.java
index 1578743..725e977 100644
--- a/imixs-ai-workflow/src/main/java/org/imixs/ai/workflow/OpenAIAPIService.java
+++ b/imixs-ai-workflow/src/main/java/org/imixs/ai/workflow/OpenAIAPIService.java
@@ -60,19 +60,24 @@ public class OpenAIAPIService implements Serializable {
     private static final long serialVersionUID = 1L;
     private static Logger logger = Logger.getLogger(OpenAIAPIService.class.getName());
 
-    public static final String ERROR_PROMPT_TEMPLATE = "ERROR_PROMPT_TEMPLATE";
-    public static final String ERROR_PROMPT_INFERENCE = "ERROR_PROMPT_INFERENCE";
+    public static final String ERROR_API = "ERROR_LLM_API";
+    public static final String ERROR_PROMPT_TEMPLATE = "ERROR_LLM_PROMPT_TEMPLATE";
+    public static final String ERROR_PROMPT_INFERENCE = "ERROR_LLM_PROMPT_INFERENCE";
     public static final String ITEM_AI_RESULT = "ai.result";
     public static final String ITEM_AI_RESULT_ITEM = "ai.result.item";
     public static final String ITEM_SUGGEST_ITEMS = "ai.suggest.items";
     public static final String ITEM_SUGGEST_MODE = "ai.suggest.mode";
 
-    public static final String LLM_SERVICE_ENDPOINT = "llm.service.endpoint";
     public static final String LLM_MODEL = "llm.model";
 
-    public static final String ENV_LLM_SERVICE_ENDPOINT_USER = "LLM_SERVICE_ENDPOINT_USER";
-    public static final String ENV_LLM_SERVICE_ENDPOINT_PASSWORD = "LLM_SERVICE_ENDPOINT_PASSWORD";
-    public static final String ENV_LLM_SERVICE_ENDPOINT_TIMEOUT = "LLM_SERVICE_TIMEOUT";
+    public static final String ENV_LLM_SERVICE_ENDPOINT = "llm.service.endpoint";
+    public static final String ENV_LLM_SERVICE_ENDPOINT_USER = "llm.service.endpoint.user";
+    public static final String ENV_LLM_SERVICE_ENDPOINT_PASSWORD = "llm.service.endpoint.password";
+    public static final String ENV_LLM_SERVICE_ENDPOINT_TIMEOUT = "llm.service.timeout";
+
+    @Inject
+    @ConfigProperty(name = ENV_LLM_SERVICE_ENDPOINT)
+    Optional<String> serviceEndpoint;
 
     @Inject
     @ConfigProperty(name = ENV_LLM_SERVICE_ENDPOINT_USER)
@@ -192,10 +197,13 @@ public String buildPrompt(String promptTemplate, ItemCollection workitem) throws
     }
 
     /**
-     * This method POST a given prompt to the endpoint '/completion' and returns the
-     * predicted completion.
-     * The method returns the response body.
-     * 
+     * This method POSTs a LLM Prompt to the service endpoint '/completion' and
+     * returns the predicted completion. The method returns the response body.
+     * <p>
+     * The endpoint is optional and can be null. In the endpoint is not provided the
+     * method resolves the endpoint from the environment variable
+     * <code>llm.service.endpoint</code>.
+     * <p>
      * The method optional test if the environment variables
      * LLM_SERVICE_ENDPOINT_USER and LLM_SERVICE_ENDPOINT_PASSWORD are set. In this
      * case a BASIC Authentication is used for the connection to the LLMService.
@@ -212,13 +220,23 @@ public String buildPrompt(String promptTemplate, ItemCollection workitem) throws
      * --data '{"prompt": "Building a website can be done in 10 simple
      * steps:","n_predict": 128}'
      * 
-     * @param xmlPromptData
+     * @param jsonPromptObject - an LLM json prompt object
+     * @param apiEndpoint      - optional service endpoint
      * @throws PluginException
      */
-    public String postPromptCompletion(String apiEndpoint, JsonObject jsonPromptObject)
+    public String postPromptCompletion(JsonObject jsonPromptObject, String apiEndpoint)
             throws PluginException {
         String response = null;
+
         try {
+            if (apiEndpoint == null) {
+                // default to global endpoint
+                if (!serviceEndpoint.isPresent()) {
+                    throw new PluginException(OpenAIAPIService.class.getSimpleName(), ERROR_API,
+                            "imixs-ai llm service endpoint is empty!");
+                }
+                apiEndpoint = serviceEndpoint.get();
+            }
             if (!apiEndpoint.endsWith("/")) {
                 apiEndpoint = apiEndpoint + "/";
             }