Ensure first message is user message for anthropic

posit-dev · Jul 15, 2024 · b244bb7 · b244bb7
1 parent 6611277
commit b244bb7
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Showing 2 changed files with 14 additions and 7 deletions.
diff --git a/shiny/ui/_chat.py b/shiny/ui/_chat.py
@@ -466,7 +466,7 @@ def messages(
 
         messages = self._messages()
         if token_limits is not None:
-            messages = self._trim_messages(messages, token_limits)
+            messages = self._trim_messages(messages, token_limits, format)
 
         res: list[ChatMessage | ProviderMessage] = []
         for i, m in enumerate(messages):
@@ -827,7 +827,8 @@ def _store_message(
     @staticmethod
     def _trim_messages(
         messages: tuple[StoredMessage, ...],
-        token_limits: tuple[int, int] = (4096, 1000),
+        token_limits: tuple[int, int],
+        format: MISSING_TYPE | ProviderMessageFormat,
     ) -> tuple[StoredMessage, ...]:
 
         n_total, n_reserve = token_limits
@@ -872,6 +873,11 @@ def _trim_messages(
             if remaining_non_system_tokens >= 0:
                 messages2.append(m)
 
+        if format == "anthropic":
+            # For anthropic, the first message must be a user message.
+            while messages2[-1]["role"] != "user":
+                messages2.pop()
+
         messages2.reverse()
 
         if len(messages2) == n_system_messages and n_other_messages > 0:

diff --git a/tests/pytest/test_chat.py b/tests/pytest/test_chat.py
@@ -9,6 +9,7 @@
 from shiny import Session
 from shiny._namespaces import ResolvedId, Root
 from shiny.session import session_context
+from shiny.types import MISSING
 from shiny.ui import Chat
 from shiny.ui._chat import as_transformed_message
 from shiny.ui._chat_normalize import normalize_message, normalize_message_chunk
@@ -66,7 +67,7 @@ def test_chat_message_trimming():
 
         # Throws since system message is too long
         with pytest.raises(ValueError):
-            chat._trim_messages(msgs, token_limits=(100, 0))
+            chat._trim_messages(msgs, token_limits=(100, 0), format=MISSING)
 
         msgs = (
             as_stored_message(
@@ -79,10 +80,10 @@ def test_chat_message_trimming():
 
         # Throws since only the system message fits
         with pytest.raises(ValueError):
-            chat._trim_messages(msgs, token_limits=(100, 0))
+            chat._trim_messages(msgs, token_limits=(100, 0), format=MISSING)
 
         # Raising the limit should allow both messages to fit
-        trimmed = chat._trim_messages(msgs, token_limits=(102, 0))
+        trimmed = chat._trim_messages(msgs, token_limits=(102, 0), format=MISSING)
         assert len(trimmed) == 2
         contents = [msg["content_server"] for msg in trimmed]
         assert contents == ["System message", "User message"]
@@ -100,7 +101,7 @@ def test_chat_message_trimming():
         )
 
         # Should discard the 1st user message
-        trimmed = chat._trim_messages(msgs, token_limits=(102, 0))
+        trimmed = chat._trim_messages(msgs, token_limits=(102, 0), format=MISSING)
         assert len(trimmed) == 2
         contents = [msg["content_server"] for msg in trimmed]
         assert contents == ["System message", "User message 2"]
@@ -121,7 +122,7 @@ def test_chat_message_trimming():
         )
 
         # Should discard the 1st user message
-        trimmed = chat._trim_messages(msgs, token_limits=(102, 0))
+        trimmed = chat._trim_messages(msgs, token_limits=(102, 0), format=MISSING)
         assert len(trimmed) == 3
         contents = [msg["content_server"] for msg in trimmed]
         assert contents == ["System message", "System message 2", "User message 2"]