server: collect nested tool call objects when parsing (#5824)

server/model.go

@@ -344,6 +344,10 @@ func (m *Model) parseToolCalls(s string) ([]api.ToolCall, bool) {
 		}
 	}
 
+	if name == "" || arguments == "" {
+		return nil, false
+	}
+
 	var objs []map[string]any
 	for offset := 0; offset < len(s); {
 		var obj map[string]any
@@ -361,23 +365,40 @@ func (m *Model) parseToolCalls(s string) ([]api.ToolCall, bool) {
 			return nil, false
 		} else {
 			offset += int(decoder.InputOffset())
-			objs = append(objs, obj)
+
+			// collect all nested objects
+			var collect func(any) []map[string]any
+			collect = func(obj any) (all []map[string]any) {
+				switch o := obj.(type) {
+				case map[string]any:
+					all = append(all, o)
+					for _, v := range o {
+						all = append(all, collect(v)...)
+					}
+				case []any:
+					for _, v := range o {
+						all = append(all, collect(v)...)
+					}
+				}
+
+				return all
+			}
+			objs = append(objs, collect(obj)...)
 		}
 	}
 
 	var toolCalls []api.ToolCall
 	for _, kv := range objs {
-		var call api.ToolCall
-		for k, v := range kv {
-			switch k {
-			case name:
-				call.Function.Name = v.(string)
-			case arguments:
-				call.Function.Arguments = v.(map[string]any)
-			}
+		n, nok := kv[name].(string)
+		a, aok := kv[arguments].(map[string]any)
+		if nok && aok {
+			toolCalls = append(toolCalls, api.ToolCall{
+				Function: api.ToolCallFunction{
+					Name:      n,
+					Arguments: a,
+				},
+			})
 		}
-
-		toolCalls = append(toolCalls, call)
 	}
 
 	return toolCalls, len(toolCalls) > 0