Good — both adapters handle dict arguments correctly. The OpenAI adapter at line 663 normalizes `dict → json.dumps()` before sending, and the Anthropic adapter at line 420 handles both string and dict. So the behavioral change (keeping arguments as dict instead of JSON string) is safe — the adapters normalize on the way out.

Now let me check the redundant `tool_calls` guard on line 207:

Looking at `_build_subagent_assistant_tool_history_msg` (line 185): it's only called from `_handle_feature_tool_calls` where `response.tool_calls` is already confirmed truthy (lines 770, 866-867, 872). The guard on line 207 (`if reasoning_content and getattr(response, "tool_calls", None)`) is redundant but harmless — it's defensive.

**Review of PR #1337:**

**Previous concerns resolved:** The PR consolidates three copy-pasted inline message-building blocks into a single `_build_subagent_assistant_tool_history_msg` method, which is a clean deduplication. Reasoning content (`reasoning_content`) is now replayed into the tool history messages so providers like DeepSeek/QwQ don't lose their chain-of-thought across tool loops.

**Behavioral change (non-blocking):** The old code used `json.dumps(tc.arguments)` for dict arguments (serializing to string); the new code keeps them as dicts via `tc.arguments if isinstance(tc.arguments, dict)`. This is safe — both the OpenAI adapter (line 663, normalizes dict→string) and Anthropic adapter (line 420, parses string→dict) handle either format. The new behavior is actually more correct since it avoids double-serialization if an adapter also calls `json.dumps`.

**No blocking issues found.** The extraction logic in `_extract_response_reasoning_content` correctly handles both dict-raw (line 173) and OpenAI-style object-raw (line 178) responses with appropriate fallbacks. The test covers the dict-raw path and validates the full round-trip through `_handle_feature_tool_calls`.

One minor nit (non-blocking): the `getattr(response, "tool_calls", None)` check on line 207 is always true at all call sites, but it's harmless defensive code.

**Verdict: No blockers. Approve.**
