steps B.3/B.4/B.5 complete: bidirectional WS handler, _tool_loop verified, clean final frame

app/core/orchestrator.py

@@ -144,14 +144,15 @@ async def orchestrate_stream(
     request: ChatRequest,
     reg: AgentRegistry | None = None,
 ) -> AsyncGenerator[str, None]:
-    """Streaming orchestration — yields text chunks then a final JSON frame.
+    """Streaming orchestration — yields plain text chunks only.
 
-    The final frame is a JSON object:
-    ``{"done": true, "response": "...", "actions": []}``.
+    The WebSocket handler in ``app/api/routes/chat.py`` is responsible for
+    wrapping each chunk in a ``text_chunk`` frame and sending the final
+    ``final`` frame once the generator is exhausted.
 
     Agents do not yet support token-level streaming; the full response is
-    fetched first, then emitted in fixed-size chunks.  Token-level streaming
-    will be wired in Step 6 when agents expose ``astream()``.
+    fetched first (which may involve multiple WS round-trips for tool calls),
+    then emitted in fixed-size chunks.
     """
     if reg is None:
         reg = _default_registry
@@ -163,6 +164,3 @@ async def orchestrate_stream(
     chunk_size = 50
     for i in range(0, len(response_text), chunk_size):
         yield response_text[i : i + chunk_size]
-
-    final = ChatResponse(response=response_text)
-    yield json.dumps({"done": True, **final.model_dump()})