diff --git a/internal/server/server.go b/internal/server/server.go
index ced8c25e..d695088b 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -381,6 +381,17 @@ func (s *Server) handleChatCompletions(c *gin.Context) {
 		ToolChoice:       req.ToolChoice,
 	}
 
+	// Inject max_tokens from model registry when client doesn't specify one.
+	// Prevents providers from applying a low default output cap.
+	if unifiedReq.MaxTokens == nil {
+		s.registryMu.RLock()
+		meta := s.registry.FindModel(modelID)
+		s.registryMu.RUnlock()
+		if meta != nil && meta.Limit != nil && meta.Limit.Output > 0 {
+			unifiedReq.MaxTokens = &meta.Limit.Output
+		}
+	}
+
 	// Handle Stop sequences
 	if req.Stop != nil {
 		var stop []string