fix: only warn about truncation when the stop reason is max_tokens

pr_split/logs.py

@@ -103,6 +103,7 @@
     " the diff will be sent to that host"
 )
 LLM_OUTPUT_INCOMPLETE = "LLM output incomplete (status: {status}, reason: {reason})"
+LLM_UNEXPECTED_STOP = "LLM stopped with stop_reason={stop_reason} (keys in tool input: {keys})"
 CHUNK_RETRY = "Chunk {index}/{total} failed (attempt {attempt}), retrying: {error}"
 INVALID_HUNK_INDEX = (
     "Group '{group}': invalid hunk index {index} for {file} (max: {max}), skipping"

pr_split/planner/client.py

@@ -181,9 +181,12 @@ def _call_anthropic(system: str, user: str, *, settings: Settings) -> RawToolOut
             if isinstance(block, BetaToolUseBlock) and isinstance(block.input, dict):
                 keys = list(block.input.keys())
                 break
-        logger.warning(logs.LLM_OUTPUT_TRUNCATED.format(stop_reason=stop_reason, keys=keys))
         if stop_reason == "max_tokens":
+            logger.warning(logs.LLM_OUTPUT_TRUNCATED.format(stop_reason=stop_reason, keys=keys))
             raise LLMError(ErrorMsg.LLM_OUTPUT_TRUNCATED(detail=f"stop_reason={stop_reason}"))
+        # Any other stop reason is not a truncation; if a tool block is
+        # present the plan is complete, otherwise the loop below reports it.
+        logger.debug(logs.LLM_UNEXPECTED_STOP.format(stop_reason=stop_reason, keys=keys))
     for block in response.content:
         if isinstance(block, BetaToolUseBlock) and block.name == SPLIT_TOOL_NAME:
             return RawToolOutput(groups=_extract_raw_output(block.input))

tests/test_client.py

@@ -1337,6 +1337,25 @@ def test_failed_status_falls_back_to_error_code(self, mock_cls: MagicMock) -> No
             _call_openai("sys", "usr", settings=_make_settings(Provider.OPENAI))
 
 
+class TestTruncationWarningScope:
+    @patch("pr_split.planner.client.logger")
+    @patch("pr_split.planner.client.anthropic.Anthropic")
+    def test_end_turn_with_tool_block_does_not_warn_truncated(
+        self, mock_cls: MagicMock, mock_logger: MagicMock
+    ) -> None:
+        from anthropic.types.beta import BetaToolUseBlock
+
+        block = BetaToolUseBlock(
+            id="tu_1", type="tool_use", name=SPLIT_TOOL_NAME, input={"groups": _SAMPLE_RAW_GROUPS}
+        )
+        mock_cls.return_value.beta.messages.create.return_value = SimpleNamespace(
+            stop_reason="end_turn", content=[block]
+        )
+        result = _call_anthropic("sys", "usr", settings=_make_settings(Provider.ANTHROPIC))
+        assert result["groups"] == _SAMPLE_RAW_GROUPS
+        assert not any("truncated" in str(c.args[0]) for c in mock_logger.warning.call_args_list)
+
+
 class TestMergeChunkGroupsSameFile:
     def test_same_file_in_later_chunk_is_merged_into_one_assignment(self) -> None:
         first = Group(