tool-call: ensure there's always a non-empty tool call id (#12292)

examples/server/server.cpp

@@ -751,7 +751,10 @@ struct server_task_result_cmpl_final : server_task_result {
                         {"name", tc.name},
                         {"arguments", tc.arguments},
                     }},
-                    {"id", tc.id},
+                    // Some templates generate and require an id (sometimes in a very specific format, e.g. Mistral Nemo).
+                    // We only generate a random id for the ones that don't generate one by themselves
+                    // (they also won't get to see it as their template likely doesn't use it, so it's all for the client)
+                    {"id", tc.id.empty() ? gen_tool_call_id() : tc.id},
                 });
             }
             message["tool_calls"] = tool_calls;

examples/server/tests/unit/test_tool_call.py

@@ -92,6 +92,7 @@ def do_test_completion_with_required_tool_tiny(server: ServerProcess, tool: dict
     assert tool_calls and len(tool_calls) == 1, f'Expected 1 tool call in {choice["message"]}'
     tool_call = tool_calls[0]
     assert choice["message"].get("content") in (None, ""), f'Expected no content in {choice["message"]}'
+    assert len(tool_call.get("id", "")) > 0, f'Expected non empty tool call id in {tool_call}'
     expected_function_name = "python" if tool["type"] == "code_interpreter" else tool["function"]["name"]
     assert expected_function_name == tool_call["function"]["name"]
     actual_arguments = tool_call["function"]["arguments"]
@@ -373,6 +374,7 @@ def do_test_weather(server: ServerProcess, **kwargs):
     tool_call = tool_calls[0]
     # assert choice["message"].get("content") in (None, ""), f'Expected no content in {choice["message"]}'
     assert tool_call["function"]["name"] == WEATHER_TOOL["function"]["name"], f'Expected weather tool call, got {tool_call["function"]["name"]}'
+    assert len(tool_call.get("id", "")) > 0, f'Expected non empty tool call id in {tool_call}'
     actual_arguments = json.loads(tool_call["function"]["arguments"])
     assert 'location' in actual_arguments, f"location not found in {json.dumps(actual_arguments)}"
     location = actual_arguments["location"]
@@ -596,6 +598,7 @@ def do_test_hello_world(server: ServerProcess, **kwargs):
     tool_call = tool_calls[0]
     # assert choice["message"].get("content") in (None, ""), f'Expected no content in {choice["message"]}'
     assert tool_call["function"]["name"] == PYTHON_TOOL["function"]["name"]
+    assert len(tool_call.get("id", "")) > 0, f'Expected non empty tool call id in {tool_call}'
     actual_arguments = json.loads(tool_call["function"]["arguments"])
     assert 'code' in actual_arguments, f"code not found in {json.dumps(actual_arguments)}"
     code = actual_arguments["code"]

examples/server/utils.hpp

@@ -435,6 +435,10 @@ static std::string gen_chatcmplid() {
     return "chatcmpl-" + random_string();
 }
 
+static std::string gen_tool_call_id() {
+    return random_string();
+}
+
 //
 // other common utils
 //