fix: code review P0/P1 fixes — history param bug, llm dict access, WS ping

- Fix P0: _build_history_messages(conv.id, message_text) passed string as
  limit param causing TypeError at runtime — removed erroneous second arg
- Fix P0: llm.py /llm/models used attribute access on dict (model_config.max_tokens)
  causing AttributeError — changed to dict.get() access
- Fix P1: Portal WS ignored ping messages — added pong response handler
- Fix: composition.py f-string without placeholders

src/agentkit/server/routes/llm.py

@@ -30,9 +30,9 @@ async def list_models(req: Request):
                 "id": f"{provider_name}/{model_name}",
                 "provider": provider_name,
                 "model": model_name,
-                "max_tokens": model_config.max_tokens,
-                "cost_per_1k_input": model_config.cost_per_1k_input,
-                "cost_per_1k_output": model_config.cost_per_1k_output,
+                "max_tokens": model_config.get("max_tokens"),
+                "cost_per_1k_input": model_config.get("cost_per_1k_input"),
+                "cost_per_1k_output": model_config.get("cost_per_1k_output"),
             })
 
     aliases = config.model_aliases if config.model_aliases else {}

src/agentkit/server/routes/portal.py

@@ -571,6 +571,10 @@ async def portal_websocket(websocket: WebSocket):
                 await websocket.send_json({"type": "result", "data": {"status": "cancelled"}})
                 return
 
+            if msg_type == "ping":
+                await websocket.send_json({"type": "pong"})
+                continue
+
             if msg_type != "chat":
                 continue
 
@@ -683,7 +687,7 @@ async def portal_websocket(websocket: WebSocket):
                     )
                 chat_messages.append({"role": "user", "content": message_text})
                 # Inject conversation history for context continuity
-                history_msgs = _build_history_messages(conv.id, message_text)
+                history_msgs = _build_history_messages(conv.id)
                 for hm in history_msgs:
                     chat_messages.insert(-1, hm)
                 response = await llm_gateway.chat(

src/agentkit/tools/composition.py

@@ -223,7 +223,7 @@ class DynamicSelector(Tool):
         prompt = (
             f"Given the following input:\n{json.dumps(kwargs, ensure_ascii=False)}\n\n"
             f"Available tools:\n" + "\n".join(tool_descriptions) + "\n\n"
-            f"Which tool number should be used? Reply with just the number."
+            "Which tool number should be used? Reply with just the number."
         )
 
         try: