diff --git a/common/common.cpp b/common/common.cpp
index 26250abb6c..0b8047c480 100644
--- a/common/common.cpp
+++ b/common/common.cpp
@@ -1195,6 +1195,9 @@ llama_context * common_init_result::context() {
 }
 
 common_sampler * common_init_result::sampler(llama_seq_id seq_id) {
+    if (pimpl->samplers.size() <= (size_t) seq_id) {
+        return nullptr;
+    }
     return pimpl->samplers[seq_id].get();
 }
 
diff --git a/tools/completion/completion.cpp b/tools/completion/completion.cpp
index f368a2f4c6..d9ac94babb 100644
--- a/tools/completion/completion.cpp
+++ b/tools/completion/completion.cpp
@@ -144,6 +144,10 @@ int main(int argc, char ** argv) {
     ctx   = llama_init->context();
     model = llama_init->model();
     smpl  = llama_init->sampler(0);
+    if (smpl == NULL) {
+        LOG_ERR("%s: error: unable to create sampler\n", __func__);
+        return 1;
+    }
 
     if (ctx == NULL) {
         LOG_ERR("%s: error: unable to create context\n", __func__);