thinking: force newer qwen3 models to always use thinking

server/routes.go

@@ -63,6 +63,15 @@ func shouldUseHarmony(model *Model) bool {
 	return false
 }
 
+func shouldForceThinking(model *Model) bool {
+	if model.Config.ModelFamily == "qwen3" && strings.Contains(model.Name, "thinking-2507") {
+		// Force thinking mode for the newer qwen3 thinking models otherwise they end up
+		// leaving the thinking trace in the return content w/ unmatched <think></think> tags
+		return true
+	}
+	return false
+}
+
 func experimentEnabled(name string) bool {
 	return slices.Contains(strings.Split(os.Getenv("OLLAMA_EXPERIMENT"), ","), name)
 }
@@ -330,7 +339,10 @@ func (s *Server) GenerateHandler(c *gin.Context) {
 	if req.Suffix != "" {
 		caps = append(caps, model.CapabilityInsert)
 	}
-	if req.Think != nil && req.Think.Bool() {
+	if req.Think == nil && shouldForceThinking(m) {
+		req.Think = &api.ThinkValue{Value: true}
+		caps = append(caps, model.CapabilityThinking)
+	} else if req.Think != nil && req.Think.Bool() {
 		caps = append(caps, model.CapabilityThinking)
 		// TODO(drifkin): consider adding a warning if it's false and the model
 		// doesn't support thinking. It's not strictly required, but it can be a
@@ -1871,7 +1883,10 @@ func (s *Server) ChatHandler(c *gin.Context) {
 	if len(req.Tools) > 0 {
 		caps = append(caps, model.CapabilityTools)
 	}
-	if req.Think != nil && req.Think.Bool() {
+	if req.Think == nil && shouldForceThinking(m) {
+		req.Think = &api.ThinkValue{Value: true}
+		caps = append(caps, model.CapabilityThinking)
+	} else if req.Think != nil && req.Think.Bool() {
 		caps = append(caps, model.CapabilityThinking)
 	}