refactor: address code review feedback on MCP tool calling

steward/bot/telegram.py

@@ -371,7 +371,7 @@ async def message_handler(update: Update, context: ContextTypes.DEFAULT_TYPE) ->
         if tool_client is not None:
             reply = await llm.chat_with_tools(text, tool_client, history=call_history)
         else:
-            reply = await llm.chat(text, history=call_history)  # type: ignore[arg-type]
+            reply = await llm.chat(text, history=call_history)
         history.append({"role": "user", "content": text})
         history.append({"role": "assistant", "content": reply})
     else:
@@ -381,7 +381,7 @@ async def message_handler(update: Update, context: ContextTypes.DEFAULT_TYPE) ->
         if tool_client is not None:
             reply = await llm.chat_with_tools(text, tool_client, history=call_history)
         else:
-            reply = await llm.chat(text, history=call_history)  # type: ignore[arg-type]
+            reply = await llm.chat(text, history=call_history)
         user_history.append({"role": "user", "content": text})
         user_history.append({"role": "assistant", "content": reply})
         if len(user_history) > _MAX_HISTORY * 2:

steward/llm/client.py

@@ -29,12 +29,12 @@ class LLMClient:
         self,
         user_message: str,
         *,
-        history: list[dict[str, str]] | None = None,
+        history: list[dict[str, Any]] | None = None,
         system_prompt: str | None = None,
     ) -> str:
         """Send a user message (with optional history) and return the assistant reply."""
         system = system_prompt or self._settings.openai_system_prompt
-        messages: list[dict[str, str]] = [{"role": "system", "content": system}]
+        messages: list[dict[str, Any]] = [{"role": "system", "content": system}]
         if history:
             messages.extend(history)
         messages.append({"role": "user", "content": user_message})
@@ -130,8 +130,13 @@ class LLMClient:
 
             # Execute each tool and append results
             for tc in msg.tool_calls:
+                try:
                     try:
                         args = json.loads(tc.function.arguments)
+                    except json.JSONDecodeError as exc:
+                        raise ValueError(
+                            f"Invalid JSON in tool arguments for '{tc.function.name}': {exc}"
+                        ) from exc
                     result = await tool_client.call(tc.function.name, args)
                     logger.info("Tool %s → %d chars", tc.function.name, len(result))
                 except Exception as exc:
@@ -153,12 +158,12 @@ class LLMClient:
         self,
         user_message: str,
         *,
-        history: list[dict[str, str]] | None = None,
+        history: list[dict[str, Any]] | None = None,
         system_prompt: str | None = None,
     ) -> AsyncIterator[str]:
         """Stream the assistant reply token by token."""
         system = system_prompt or self._settings.openai_system_prompt
-        messages: list[dict[str, str]] = [{"role": "system", "content": system}]
+        messages: list[dict[str, Any]] = [{"role": "system", "content": system}]
         if history:
             messages.extend(history)
         messages.append({"role": "user", "content": user_message})

steward/tools/client.py

@@ -40,7 +40,7 @@ class ToolClient:
     def _headers(self) -> dict[str, str]:
         headers: dict[str, str] = {"Accept": "application/json"}
         if self._api_key:
-            headers["Authorization"] = "Bearer " + self._api_key
+            headers["Authorization"] = "Bearer " + self._api_key.strip()
         return headers
 
     async def get_spec(self) -> dict[str, Any]: