Improve exception hygiene: Add exc_info=True to logger calls

- session_key_resolver.py: Add exc_info=True to logger.warning in ValueError handler
- model_utils.py: Add exc_info=True to logger.error in Exception handler
- sse_bytes_parser.py: Add exc_info=True to logger.warning in ValueError handler

These changes improve debuggability by including stack traces when exceptions
are logged in critical paths (session management, model parsing, streaming).

Author: Mateusz

src/core/domain/model_utils.py

@@ -175,12 +175,13 @@ def parse_model_with_params(
             parsed_model = parse_model_backend(model, default_backend)
             backend_type = parsed_model.backend_type
             model_name = parsed_model.model_name
-        except Exception as fallback_error:
-            # If even the fallback fails, log error and use defaults
-            logger.error(
-                f"Failed to parse model string '{model}' even without URI parameters: {fallback_error}. "
-                f"Using default backend '{default_backend}' and model '{model}'."
-            )
+        except Exception as fallback_error:
+            # If even the fallback fails, log error and use defaults
+            logger.error(
+                f"Failed to parse model string '{model}' even without URI parameters: {fallback_error}. "
+                f"Using default backend '{default_backend}' and model '{model}'.",
+                exc_info=True,
+            )
             backend_type = default_backend if default_backend else "openai"
             model_name = model
         return ParsedModelWithParams(

src/core/domain/streaming/parsing/sse_bytes_parser.py

@@ -82,7 +82,9 @@ def parse(self, raw_data: Any) -> StreamingContent:
                         return StreamingContent(content=json_part, raw_data=raw_data)
                     except ValueError as e:
                         if "depth" in str(e).lower():
-                            logger.warning("JSON payload too deeply nested: %s", e)
+                            logger.warning(
+                                "JSON payload too deeply nested: %s", e, exc_info=True
+                            )
                             # Reject deeply nested JSON completely for security
                             raise ValueError(f"JSON payload too deeply nested: {e}")
                         raise

src/core/transport/session_key_resolver.py

@@ -107,14 +107,15 @@ def resolve_session_key_from_request_context(
             primary_id=request_id.strip(),
             group_id=group_id,
         )
-    except ValueError as e:
-        # SessionKey validation failed (e.g., empty primary_id after strip)
-        if logger.isEnabledFor(logging.WARNING):
-            logger.warning(
-                "Failed to create SessionKey from context: %s",
-                e,
-                extra={"request_id": request_id},
-            )
+    except ValueError as e:
+        # SessionKey validation failed (e.g., empty primary_id after strip)
+        if logger.isEnabledFor(logging.WARNING):
+            logger.warning(
+                "Failed to create SessionKey from context: %s",
+                e,
+                exc_info=True,
+                extra={"request_id": request_id},
+            )
         return None