Use beam search in whisper, tell the model about misheard words

Whisper wrote "Che ori sono?" twice in one day and the model once
answered with the weather. On 10 recorded short questions beam search
(beam_size=5) gets 9 right against 8 for greedy, for 0.06 s more; an
initial prompt also got 9 but lost one question entirely, so it is not
used.

The default system prompt now says the user's words come from speech
recognition and should be read by how they sound: on "Che ori sono?"
stray tool calls went from 1 in 10 to none, other tools unaffected.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/assistant.py b/assistant.py
index bf6049a..991dfa0 100644
--- a/assistant.py
+++ b/assistant.py
@@ -52,6 +52,8 @@ DEFAULTS = {
                "briefly in plain sentences: no markdown, no lists, no emoji. "
                "Reply in the language the user speaks, Italian or English. "
                "Write numbers, times and dates in digits, never spelled out. "
+               "The user's words come from speech recognition and may contain "
+               "misheard words: read them by how they sound. "
                "Facts about the user's computer, devices, accounts, mail, calendar "
                "or money come only from a tool: call one, and if none can tell, "
                "say you do not know. Never guess them."),
@@ -261,7 +263,9 @@ def envelope(audio, sr):
 
 def transcribe(lang="auto"):
     # Always send language: whisper-server's own default is en, not auto.
+    # Beam search: 9/10 test clips right vs 8/10 greedy, +0.06 s.
     out = subprocess.run(["curl", "-s", "-F", f"file=@{WAV}", "-F", f"language={lang}",
+                          "-F", "beam_size=5",
                           "-F", "response_format=verbose_json", WHISPER + "/inference"],
                          capture_output=True, text=True).stdout
     d = json.loads(out)