diff --git a/core/http/endpoints/openai/chat.go b/core/http/endpoints/openai/chat.go
index 86b75601bc45..12a14eace4fb 100644
--- a/core/http/endpoints/openai/chat.go
+++ b/core/http/endpoints/openai/chat.go
@@ -172,6 +172,14 @@ func ChatEndpoint(cl *config.BackendConfigLoader, ml *model.ModelLoader, startup
 
 		funcs := input.Functions
 		shouldUseFn := len(input.Functions) > 0 && config.ShouldUseFunctions()
+		strictMode := false
+
+		for _, f := range input.Functions {
+			if f.Strict {
+				strictMode = true
+				break
+			}
+		}
 
 		// Allow the user to set custom actions via config file
 		// to be "embedded" in each model
@@ -187,10 +195,33 @@ func ChatEndpoint(cl *config.BackendConfigLoader, ml *model.ModelLoader, startup
 
 		if config.ResponseFormatMap != nil {
 			d := schema.ChatCompletionResponseFormat{}
-			dat, _ := json.Marshal(config.ResponseFormatMap)
-			_ = json.Unmarshal(dat, &d)
+			dat, err := json.Marshal(config.ResponseFormatMap)
+			if err != nil {
+				return err
+			}
+			err = json.Unmarshal(dat, &d)
+			if err != nil {
+				return err
+			}
 			if d.Type == "json_object" {
 				input.Grammar = functions.JSONBNF
+			} else if d.Type == "json_schema" {
+				d := schema.JsonSchemaRequest{}
+				dat, err := json.Marshal(config.ResponseFormatMap)
+				if err != nil {
+					return err
+				}
+				err = json.Unmarshal(dat, &d)
+				if err != nil {
+					return err
+				}
+				fs := &functions.JSONFunctionStructure{
+					AnyOf: []functions.Item{d.JsonSchema.Schema},
+				}
+				g, err := fs.Grammar(config.FunctionsConfig.GrammarOptions()...)
+				if err == nil {
+					input.Grammar = g
+				}
 			}
 		}
 
@@ -201,7 +232,7 @@ func ChatEndpoint(cl *config.BackendConfigLoader, ml *model.ModelLoader, startup
 		}
 
 		switch {
-		case !config.FunctionsConfig.GrammarConfig.NoGrammar && shouldUseFn:
+		case (!config.FunctionsConfig.GrammarConfig.NoGrammar || strictMode) && shouldUseFn:
 			noActionGrammar := functions.Function{
 				Name:        noActionName,
 				Description: noActionDescription,
diff --git a/core/schema/openai.go b/core/schema/openai.go
index 3b39eaf3c7c6..fe4745bfcbd6 100644
--- a/core/schema/openai.go
+++ b/core/schema/openai.go
@@ -139,6 +139,17 @@ type ChatCompletionResponseFormat struct {
 	Type ChatCompletionResponseFormatType `json:"type,omitempty"`
 }
 
+type JsonSchemaRequest struct {
+	Type       string     `json:"type"`
+	JsonSchema JsonSchema `json:"json_schema"`
+}
+
+type JsonSchema struct {
+	Name   string         `json:"name"`
+	Strict bool           `json:"strict"`
+	Schema functions.Item `json:"schema"`
+}
+
 type OpenAIRequest struct {
 	PredictionOptions
 
diff --git a/pkg/functions/functions.go b/pkg/functions/functions.go
index 19012d53dd99..1a7e1ff1711e 100644
--- a/pkg/functions/functions.go
+++ b/pkg/functions/functions.go
@@ -14,6 +14,7 @@ const (
 type Function struct {
 	Name        string                 `json:"name"`
 	Description string                 `json:"description"`
+	Strict      bool                   `json:"strict"`
 	Parameters  map[string]interface{} `json:"parameters"`
 }
 type Functions []Function