diff --git a/src/option_manager.cc b/src/option_manager.cc
index c510dff8..8d896514 100644
--- a/src/option_manager.cc
+++ b/src/option_manager.cc
@@ -115,7 +115,7 @@ void OptionManager::on_option_changed(const Option& option)
 CandidateList OptionsRegistry::complete_option_name(StringView prefix,
                                                     ByteCount cursor_pos) const
 {
-    using OptionPtr = std::unique_ptr<OptionDesc>;
+    using OptionPtr = std::unique_ptr<const OptionDesc>;
     return complete(prefix, cursor_pos, m_descs |
                     filter([](const OptionPtr& desc)
                            { return not (desc->flags() & OptionFlags::Hidden); }) |
diff --git a/src/option_manager.hh b/src/option_manager.hh
index cff6f34f..da7dd699 100644
--- a/src/option_manager.hh
+++ b/src/option_manager.hh
@@ -234,7 +234,7 @@ public:
     const OptionDesc* option_desc(StringView name) const
     {
         auto it = find_if(m_descs,
-                          [&name](const std::unique_ptr<OptionDesc>& opt)
+                          [&name](const std::unique_ptr<const OptionDesc>& opt)
                           { return opt->name() == name; });
         return it != m_descs.end() ? it->get() : nullptr;
     }
@@ -244,7 +244,7 @@ public:
     CandidateList complete_option_name(StringView prefix, ByteCount cursor_pos) const;
 private:
     OptionManager& m_global_manager;
-    Vector<std::unique_ptr<OptionDesc>, MemoryDomain::Options> m_descs;
+    Vector<std::unique_ptr<const OptionDesc>, MemoryDomain::Options> m_descs;
 };
 
 }