diff --git a/aider/commands.py b/aider/commands.py
index fe70dbe75..5a73b2411 100644
--- a/aider/commands.py
+++ b/aider/commands.py
@@ -151,6 +151,7 @@ class Commands:
         assert cmd.startswith("/")
         cmd = cmd[1:]
 
+        cmd = cmd.replace("-", "_")
         fun = getattr(self, f"completions_{cmd}", None)
         if not fun:
             return
@@ -510,7 +511,7 @@ class Commands:
             fname = f'"{fname}"'
         return fname
 
-    def completions_read(self):
+    def completions_read_only(self):
         return self.completions_add()
 
     def completions_add(self):
diff --git a/aider/io.py b/aider/io.py
index 502c9ae76..093b6403e 100644
--- a/aider/io.py
+++ b/aider/io.py
@@ -105,8 +105,10 @@ class AutoCompleter(Completer):
         cmd = words[0]
         partial = words[-1].lower()
 
-        if cmd not in self.command_names:
+        matches, _, _ = self.commands.matching_commands(cmd)
+        if len(matches) != 1:
             return
+        cmd = matches[0]
 
         if cmd not in self.command_completions:
             candidates = self.commands.get_completions(cmd)
diff --git a/tests/basic/test_io.py b/tests/basic/test_io.py
index 511cd7355..89e759dca 100644
--- a/tests/basic/test_io.py
+++ b/tests/basic/test_io.py
@@ -34,6 +34,7 @@ class TestInputOutput(unittest.TestCase):
 
             Path(fname).write_text("def hello(): pass\n")
             autocompleter = AutoCompleter(root, rel_fnames, addable_rel_fnames, commands, "utf-8")
+            autocompleter.tokenize()
             dump(autocompleter.words)
             self.assertEqual(autocompleter.words, set(rel_fnames + [("hello", "`hello`")]))