diff --git a/src/wormhole/_boss.py b/src/wormhole/_boss.py
index 6ec3298..b18ba2d 100644
--- a/src/wormhole/_boss.py
+++ b/src/wormhole/_boss.py
@@ -108,14 +108,16 @@ class Boss(object):
     def _set_trace(self, client_name, which, file):
         names = {"B": self, "N": self._N, "M": self._M, "S": self._S,
                  "O": self._O, "K": self._K, "SK": self._K._SK, "R": self._R,
-                 "RC": self._RC, "L": self._L, "C": self._C,
-                 "T": self._T}
+                 "RC": self._RC, "L": self._L, "A": self._A, "I": self._I,
+                 "C": self._C, "T": self._T}
         for machine in which.split():
             t = (lambda old_state, input, new_state, machine=machine:
                  self._print_trace(old_state, input, new_state,
                                    client_name=client_name,
                                    machine=machine, file=file))
             names[machine].set_trace(t)
+            if machine == "I":
+                self._I.set_debug(t)
 
     ## def serialize(self):
     ##     raise NotImplemented
diff --git a/src/wormhole/_input.py b/src/wormhole/_input.py
index 8c2ef1e..d2c6379 100644
--- a/src/wormhole/_input.py
+++ b/src/wormhole/_input.py
@@ -22,6 +22,13 @@ class Input(object):
         self._nameplate = None
         self._wordlist = None
         self._wordlist_waiters = []
+        self._trace = None
+
+    def set_debug(self, f):
+        self._trace = f
+    def _debug(self, what):
+        if self._trace:
+            self._trace(old_state="", input=what, new_state="")
 
     def wire(self, code, lister):
         self._C = _interfaces.ICode(code)
@@ -238,10 +245,14 @@ class Helper(object):
     def get_nameplate_completions(self, prefix):
         return self._input.get_nameplate_completions(prefix)
     def choose_nameplate(self, nameplate):
+        self._input._debug("I.choose_nameplate")
         self._input.choose_nameplate(nameplate)
+        self._input._debug("I.choose_nameplate finished")
     def when_wordlist_is_available(self):
         return self._input.when_wordlist_is_available()
     def get_word_completions(self, prefix):
         return self._input.get_word_completions(prefix)
     def choose_words(self, words):
+        self._input._debug("I.choose_words")
         self._input.choose_words(words)
+        self._input._debug("I.choose_words finished")
diff --git a/src/wormhole/wormhole.py b/src/wormhole/wormhole.py
index 7d19dc2..e58107f 100644
--- a/src/wormhole/wormhole.py
+++ b/src/wormhole/wormhole.py
@@ -214,7 +214,8 @@ class _DeferredWormhole(object):
         self._boss.close() # only need to close if it wasn't already
         return d
 
-    def debug_set_trace(self, client_name, which="B N M S O K SK R RC L C T",
+    def debug_set_trace(self, client_name,
+                        which="B N M S O K SK R RC L A I C T",
                         file=sys.stderr):
         self._boss._set_trace(client_name, which, file)