fix(agents): stop dropping self-paired tool messages during sanitation (agentscope-ai#5792)

Author: Osamaali313

src/qwenpaw/agents/utils/tool_message_utils.py

@@ -87,6 +87,17 @@ def _reorder_tool_results(msgs: list) -> list:
     result_msg_ids: set[int] = set()
     for msg in msgs:
         if isinstance(msg.content, list):
+            # Keep a message that carries its own tool_call in place (e.g. an
+            # AgentScope 2.0 self-paired assistant msg
+            # [text, tool_call, tool_result]); only standalone tool_result
+            # messages are movable. Skipping a self-carrying msg here would
+            # drop it, since its own tool_call can never re-insert it.
+            has_own_call = any(
+                _is_tool_call(block) and _block_attr(block, "id")
+                for block in msg.content
+            )
+            if has_own_call:
+                continue
             for block in msg.content:
                 if _is_tool_result(block) and _block_attr(block, "id"):
                     results_by_id.setdefault(
@@ -131,17 +142,25 @@ def _remove_unpaired_tool_messages(msgs: list) -> list:
 
     i = 0
     while i < len(msgs):
-        use_ids, _ = extract_tool_ids(msgs[i])
+        use_ids, own_results = extract_tool_ids(msgs[i])
         if not use_ids:
             i += 1
             continue
-        required = set(use_ids)
+        # A self-paired message satisfies (some of) its own tool_calls with the
+        # tool_results in the same message; only the remainder must be covered
+        # by following messages.
+        required = set(use_ids) - own_results
         j = i + 1
         result_indices: list[int] = []
         while j < len(msgs) and required:
-            _, r = extract_tool_ids(msgs[j])
+            uj, r = extract_tool_ids(msgs[j])
             if not r:
                 break
+            # A following message that also carries tool_calls (e.g. another
+            # self-paired turn) is not a result-provider for this one; stop
+            # rather than consuming it.
+            if uj:
+                break
             required -= r
             result_indices.append(j)
             j += 1
@@ -160,8 +179,10 @@ def _remove_unpaired_tool_messages(msgs: list) -> list:
     for idx, msg in enumerate(msgs):
         if idx in to_remove:
             continue
-        _, r = extract_tool_ids(msg)
-        if r and not r.issubset(surviving_use_ids):
+        u, r = extract_tool_ids(msg)
+        # A tool_result is paired if some surviving tool_call uses its id --
+        # including a tool_call in the same (self-paired) message.
+        if r and not r.issubset(surviving_use_ids | u):
             to_remove.add(idx)
 
     return [msg for idx, msg in enumerate(msgs) if idx not in to_remove]

tests/unit/agents/utils/test_tool_message_utils.py

@@ -520,3 +520,33 @@ def test_removes_unpaired_tool_use(self):
     def test_empty_messages_returns_empty(self):
         result = _sanitize_tool_messages([])
         assert result == []
+
+    def test_self_paired_message_kept_when_another_block_unpaired(self):
+        # An AgentScope 2.0 self-paired assistant message carries its own
+        # tool_use and matching tool_result (plus text). When an *unrelated*
+        # unpaired tool_use elsewhere triggers sanitation, the valid
+        # self-paired turn must NOT be dropped (previously it was silently
+        # removed, losing the text and leaving an unpaired tool_use).
+        self_paired = _msg(
+            [
+                {"type": "text", "text": "keep me"},
+                _tool_use("paired"),
+                _tool_result("paired"),
+            ],
+        )
+        msgs = [
+            _msg([_tool_use("orphan")]),  # unpaired -> triggers sanitation
+            self_paired,
+            _msg("regular message"),
+        ]
+
+        result = _sanitize_tool_messages(msgs)
+
+        assert self_paired in result, "self-paired message must be preserved"
+        # The unpaired orphan tool_use is still removed.
+        remaining_uses: set = set()
+        for m in result:
+            u, _ = extract_tool_ids(m)
+            remaining_uses |= u
+        assert "orphan" not in remaining_uses
+        assert "paired" in remaining_uses