diff --git a/api/types.go b/api/types.go
index 4e8486acf..53a9593e5 100644
--- a/api/types.go
+++ b/api/types.go
@@ -163,6 +163,7 @@ func (t *ToolCallFunctionArguments) String() string {
 
 type Tool struct {
 	Type     string       `json:"type"`
+	Items    any          `json:"items,omitempty"`
 	Function ToolFunction `json:"function"`
 }
 
@@ -213,9 +214,12 @@ type ToolFunction struct {
 	Description string `json:"description"`
 	Parameters  struct {
 		Type       string   `json:"type"`
+		Defs       any      `json:"$defs,omitempty"`
+		Items      any      `json:"items,omitempty"`
 		Required   []string `json:"required"`
 		Properties map[string]struct {
 			Type        PropertyType `json:"type"`
+			Items       any          `json:"items,omitempty"`
 			Description string       `json:"description"`
 			Enum        []any        `json:"enum,omitempty"`
 		} `json:"properties"`
diff --git a/openai/openai_test.go b/openai/openai_test.go
index 46fce7c8d..a24093ad7 100644
--- a/openai/openai_test.go
+++ b/openai/openai_test.go
@@ -281,9 +281,12 @@ func TestChatMiddleware(t *testing.T) {
 							Description: "Get the current weather",
 							Parameters: struct {
 								Type       string   `json:"type"`
+								Defs       any      `json:"$defs,omitempty"`
+								Items      any      `json:"items,omitempty"`
 								Required   []string `json:"required"`
 								Properties map[string]struct {
 									Type        api.PropertyType `json:"type"`
+									Items       any              `json:"items,omitempty"`
 									Description string           `json:"description"`
 									Enum        []any            `json:"enum,omitempty"`
 								} `json:"properties"`
@@ -292,6 +295,7 @@ func TestChatMiddleware(t *testing.T) {
 								Required: []string{"location"},
 								Properties: map[string]struct {
 									Type        api.PropertyType `json:"type"`
+									Items       any              `json:"items,omitempty"`
 									Description string           `json:"description"`
 									Enum        []any            `json:"enum,omitempty"`
 								}{
diff --git a/server/routes_generate_test.go b/server/routes_generate_test.go
index 00a50cc3d..56121d41b 100644
--- a/server/routes_generate_test.go
+++ b/server/routes_generate_test.go
@@ -370,9 +370,12 @@ func TestGenerateChat(t *testing.T) {
 					Description: "Get the current weather",
 					Parameters: struct {
 						Type       string   `json:"type"`
+						Defs       any      `json:"$defs,omitempty"`
+						Items      any      `json:"items,omitempty"`
 						Required   []string `json:"required"`
 						Properties map[string]struct {
 							Type        api.PropertyType `json:"type"`
+							Items       any              `json:"items,omitempty"`
 							Description string           `json:"description"`
 							Enum        []any            `json:"enum,omitempty"`
 						} `json:"properties"`
@@ -381,6 +384,7 @@ func TestGenerateChat(t *testing.T) {
 						Required: []string{"location"},
 						Properties: map[string]struct {
 							Type        api.PropertyType `json:"type"`
+							Items       any              `json:"items,omitempty"`
 							Description string           `json:"description"`
 							Enum        []any            `json:"enum,omitempty"`
 						}{
@@ -467,9 +471,12 @@ func TestGenerateChat(t *testing.T) {
 					Description: "Get the current weather",
 					Parameters: struct {
 						Type       string   `json:"type"`
+						Defs       any      `json:"$defs,omitempty"`
+						Items      any      `json:"items,omitempty"`
 						Required   []string `json:"required"`
 						Properties map[string]struct {
 							Type        api.PropertyType `json:"type"`
+							Items       any              `json:"items,omitempty"`
 							Description string           `json:"description"`
 							Enum        []any            `json:"enum,omitempty"`
 						} `json:"properties"`
@@ -478,6 +485,7 @@ func TestGenerateChat(t *testing.T) {
 						Required: []string{"location"},
 						Properties: map[string]struct {
 							Type        api.PropertyType `json:"type"`
+							Items       any              `json:"items,omitempty"`
 							Description string           `json:"description"`
 							Enum        []any            `json:"enum,omitempty"`
 						}{