diff --git a/lix/libcmd/repl.cc b/lix/libcmd/repl.cc
index d156deaf1..2b9eaa122 100644
--- a/lix/libcmd/repl.cc
+++ b/lix/libcmd/repl.cc
@@ -285,7 +285,7 @@ ReplExitStatus NixRepl::mainLoop()
 {
     if (isFirstRepl) {
         std::string_view debuggerNotice = "";
-        if (state.debug.repl) {
+        if (state.debug.inDebugger) {
             debuggerNotice = " debugger";
         }
         notice("Lix %1%%2%\nType :? for help.", nixVersion, debuggerNotice);
@@ -366,7 +366,7 @@ StringSet NixRepl::completePrefix(const std::string & prefix)
             }
         }
 
-        if (state.debug.repl) {
+        if (state.debug.inDebugger) {
             for (auto const & colonCmd : this->DEBUG_COMMANDS) {
                 if (colonCmd.starts_with(prefix)) {
                     completions.insert(std::string(colonCmd));
@@ -541,7 +541,7 @@ ProcessLineResult NixRepl::processLine(std::string line)
              << "                               errors\n"
              << "  :?, :help                    Brings up this help menu\n"
              ;
-        if (state.debug.repl) {
+        if (state.debug.inDebugger) {
              std::cout
              << "\n"
              << "        Debug mode commands\n"
@@ -556,14 +556,14 @@ ProcessLineResult NixRepl::processLine(std::string line)
 
     }
 
-    else if (state.debug.repl && (command == ":bt" || command == ":backtrace")) {
+    else if (state.debug.inDebugger && (command == ":bt" || command == ":backtrace")) {
         for (const auto & [idx, i] : enumerate(state.debug.traces)) {
             std::cout << "\n" << ANSI_BLUE << idx << ANSI_NORMAL << ": ";
             showDebugTrace(std::cout, state.positions, i);
         }
     }
 
-    else if (state.debug.repl && (command == ":env")) {
+    else if (state.debug.inDebugger && (command == ":env")) {
         for (const auto & [idx, i] : enumerate(state.debug.traces)) {
             if (idx == debugTraceIndex) {
                 printEnvBindings(state, i.expr, i.env);
@@ -572,7 +572,7 @@ ProcessLineResult NixRepl::processLine(std::string line)
         }
     }
 
-    else if (state.debug.repl && (command == ":st")) {
+    else if (state.debug.inDebugger && (command == ":st")) {
         try {
             // change the DebugTrace index.
             debugTraceIndex = stoi(arg);
@@ -590,13 +590,13 @@ ProcessLineResult NixRepl::processLine(std::string line)
         }
     }
 
-    else if (state.debug.repl && (command == ":s" || command == ":step")) {
+    else if (state.debug.inDebugger && (command == ":s" || command == ":step")) {
         // set flag to stop at next DebugTrace; exit repl.
         state.debug.stop = true;
         return ProcessLineResult::Continue;
     }
 
-    else if (state.debug.repl && (command == ":c" || command == ":continue")) {
+    else if (state.debug.inDebugger && (command == ":c" || command == ":continue")) {
         // set flag to run to next breakpoint or end of program; exit repl.
         state.debug.stop = false;
         return ProcessLineResult::Continue;
diff --git a/tests/functional/repl_characterization/data/debug_frames.test b/tests/functional/repl_characterization/data/debug_frames.test
new file mode 100644
index 000000000..25e28ef97
--- /dev/null
+++ b/tests/functional/repl_characterization/data/debug_frames.test
@@ -0,0 +1,73 @@
+@args --debugger
+
+:c at the root repl is not allowed since no debugger is running yet
+  nix-repl> :c
+  error: unknown command ':c'
+
+:c and other commands become available once a debugger starts
+  nix-repl> with {}; a
+  error: undefined variable 'a'
+         at «string»:1:10:
+              1| with {}; a
+               |          ^
+
+  nix-repl> :?
+  The following commands are available:
+
+    <expr>                       Evaluate and print expression
+    <x> = <expr>                 Bind expression to variable
+    :a, :add <expr>              Add attributes from resulting set to scope
+    :b <expr>                    Build a derivation
+    :bl <expr>                   Build a derivation, creating GC roots in the
+                                 working directory
+    :e, :edit <expr>             Open package or function in $EDITOR
+    :i <expr>                    Build derivation, then install result into
+                                 current profile
+    :l, :load <path>             Load Nix expression and add it to scope
+    :lf, :load-flake <ref>       Load Nix flake and add it to scope
+    :p, :print <expr>            Evaluate and print expression recursively
+                                 Strings are printed directly, without escaping.
+    :q, :quit                    Exit nix-repl
+    :r, :reload                  Reload all files
+    :sh <expr>                   Build dependencies of derivation, then start
+                                 nix-shell
+    :t <expr>                    Describe result of evaluation
+    :u <expr>                    Build derivation, then start nix-shell
+    :doc <expr>                  Show documentation for the provided function (experimental lambda support)
+    :log <expr | .drv path>      Show logs for a derivation
+    :te, :trace-enable [bool]    Enable, disable or toggle showing traces for
+                                 errors
+    :?, :help                    Brings up this help menu
+
+          Debug mode commands
+    :env             Show env stack
+    :bt, :backtrace  Show trace stack
+    :st              Show current trace
+    :st <idx>        Change to another trace in the stack
+    :c, :continue    Go until end of program, exception, or builtins.break
+    :s, :step        Go one step
+
+we can now inspect state
+  nix-repl> :bt
+  0: error: undefined variable 'a'
+  «string»:1:10
+
+       1| with {}; a
+        |          ^
+
+  1: error: Fake frame for debugging purposes
+  «string»:1:10
+
+       1| with {}; a
+        |          ^
+
+and resume execution
+  nix-repl> :c
+  error: undefined variable 'a'
+         at «string»:1:10:
+              1| with {}; a
+               |          ^
+
+the debugger is once again disabled
+  nix-repl> :c
+  error: unknown command ':c'
diff --git a/tests/functional/repl_characterization/repl_characterization.cc b/tests/functional/repl_characterization/repl_characterization.cc
index f7e5e62b2..7e33ecec0 100644
--- a/tests/functional/repl_characterization/repl_characterization.cc
+++ b/tests/functional/repl_characterization/repl_characterization.cc
@@ -186,5 +186,6 @@ REPL_TEST(repl_printing);
 REPL_TEST(stack_vars);
 REPL_TEST(errors);
 REPL_TEST(idempotent);
+REPL_TEST(debug_frames);
 
 }; // namespace nix