diff --git a/x-pack/plugins/inference/server/chat_complete/simulated_function_calling/get_system_instructions.ts b/x-pack/plugins/inference/server/chat_complete/simulated_function_calling/get_system_instructions.ts
index 848b8d1f44f07..abfc48dfa2ef2 100644
--- a/x-pack/plugins/inference/server/chat_complete/simulated_function_calling/get_system_instructions.ts
+++ b/x-pack/plugins/inference/server/chat_complete/simulated_function_calling/get_system_instructions.ts
@@ -32,6 +32,9 @@ export function getSystemMessageInstructions({
     IMPORTANT: make sure you start and end a tool call with the ${TOOL_USE_START} and ${TOOL_USE_END} markers, it MUST
     be included in the tool call.
 
+    You can only call A SINGLE TOOL at a time. Do not call multiple tools, or multiple times the same tool, in the same
+    response.
+
     You may call tools like this:
 
     ${TOOL_USE_START}
diff --git a/x-pack/plugins/observability_solution/observability_ai_assistant/server/service/client/adapters/simulate_function_calling/get_system_message_instructions.ts b/x-pack/plugins/observability_solution/observability_ai_assistant/server/service/client/adapters/simulate_function_calling/get_system_message_instructions.ts
index c80ac022ca6c0..eaf89233a2bcd 100644
--- a/x-pack/plugins/observability_solution/observability_ai_assistant/server/service/client/adapters/simulate_function_calling/get_system_message_instructions.ts
+++ b/x-pack/plugins/observability_solution/observability_ai_assistant/server/service/client/adapters/simulate_function_calling/get_system_message_instructions.ts
@@ -33,6 +33,9 @@ export function getSystemMessageInstructions({
     IMPORTANT: make sure you start and end a tool call with the ${TOOL_USE_START} and ${TOOL_USE_END} markers, it MUST
     be included in the tool call.
 
+    You can only call A SINGLE TOOL at a time. Do not call multiple tools, or multiple times the same tool, in the same
+    response.
+
     You may call tools like this:
 
     ${TOOL_USE_START}