fix(craft): potential fix for craft freezing in kube by truncating large tool call writes

backend/onyx/server/features/build/configs.py

@@ -109,6 +109,15 @@ SANDBOX_FILE_SYNC_SERVICE_ACCOUNT = os.environ.get(
 
 ENABLE_CRAFT = os.environ.get("ENABLE_CRAFT", "false").lower() == "true"
 
+# ============================================================================
+# SSE Streaming Configuration
+# ============================================================================
+
+# Maximum character length for tool call content in SSE events
+# Content exceeding this length will be truncated to prevent large payloads
+# that can cause timeouts or client disconnects during streaming
+MAX_SSE_CONTENT_LENGTH = int(os.environ.get("MAX_SSE_CONTENT_LENGTH", "500"))
+
 # ============================================================================
 # Rate Limiting Configuration
 # ============================================================================

backend/onyx/server/features/build/sandbox/kubernetes/kubernetes_sandbox_manager.py

@@ -1499,10 +1499,33 @@ echo '{tar_b64}' | base64 -d | tar -xzf -
             packet_logger.log_session_end(
                 session_id, success=True, events_count=events_count
             )
-        except Exception as e:
-            # Log failure
+        except GeneratorExit:
+            # Generator was closed by consumer (client disconnect, timeout, broken pipe)
+            # This is the most common failure mode for SSE streaming
             packet_logger.log_session_end(
-                session_id, success=False, error=str(e), events_count=events_count
+                session_id,
+                success=False,
+                error="GeneratorExit: Client disconnected or stream closed by consumer",
+                events_count=events_count,
+            )
+            raise
+        except Exception as e:
+            # Log failure from normal exceptions
+            packet_logger.log_session_end(
+                session_id,
+                success=False,
+                error=f"Exception: {str(e)}",
+                events_count=events_count,
+            )
+            raise
+        except BaseException as e:
+            # Log failure from other base exceptions (SystemExit, KeyboardInterrupt, etc.)
+            exception_type = type(e).__name__
+            packet_logger.log_session_end(
+                session_id,
+                success=False,
+                error=f"{exception_type}: {str(e) if str(e) else 'System-level interruption'}",
+                events_count=events_count,
             )
             raise
         finally:

backend/onyx/server/features/build/session/manager.py

@@ -46,6 +46,7 @@ from onyx.server.features.build.api.packet_logger import log_separator
 from onyx.server.features.build.api.packets import BuildPacket
 from onyx.server.features.build.api.packets import ErrorPacket
 from onyx.server.features.build.api.rate_limit import get_user_rate_limit_status
+from onyx.server.features.build.configs import MAX_SSE_CONTENT_LENGTH
 from onyx.server.features.build.configs import MAX_TOTAL_UPLOAD_SIZE_BYTES
 from onyx.server.features.build.configs import MAX_UPLOAD_FILES_PER_SESSION
 from onyx.server.features.build.configs import PERSISTENT_DOCUMENT_STORAGE_PATH
@@ -1338,9 +1339,57 @@ class SessionManager:
                                     db_session=self._db_session,
                                 )
 
+                    # Log full event to packet logger (can handle large payloads)
                     packet_logger.log("tool_call_progress", event_data)
                     packet_logger.log_sse_emit("tool_call_progress", session_id)
-                    yield _serialize_acp_event(acp_event, "tool_call_progress")
+
+                    # Create sanitized copy for SSE streaming to prevent massive JSON serialization
+                    # that can block the generator and cause timeouts
+                    sse_event_data = event_data.copy()
+
+                    # Truncate rawInput.content if present and large
+                    raw_input = sse_event_data.get("rawInput")
+                    if raw_input and isinstance(raw_input, dict):
+                        content = raw_input.get("content")
+                        if (
+                            content
+                            and isinstance(content, str)
+                            and len(content) > MAX_SSE_CONTENT_LENGTH
+                        ):
+                            logger.debug(
+                                f"Truncating tool_call_progress content from {len(content)} to {MAX_SSE_CONTENT_LENGTH} chars"
+                            )
+                            truncated = content[:MAX_SSE_CONTENT_LENGTH] + "..."
+                            sse_event_data["rawInput"] = {
+                                **raw_input,
+                                "content": truncated,
+                                "_truncated": True,
+                                "_originalLength": len(content),
+                            }
+
+                    # Truncate rawOutput.content if present and large
+                    raw_output = sse_event_data.get("rawOutput")
+                    if raw_output and isinstance(raw_output, dict):
+                        content = raw_output.get("content")
+                        if (
+                            content
+                            and isinstance(content, str)
+                            and len(content) > MAX_SSE_CONTENT_LENGTH
+                        ):
+                            logger.debug(
+                                f"Truncating tool_call_progress content from {len(content)} to {MAX_SSE_CONTENT_LENGTH} chars"
+                            )
+                            truncated = content[:MAX_SSE_CONTENT_LENGTH] + "..."
+                            sse_event_data["rawOutput"] = {
+                                **raw_output,
+                                "content": truncated,
+                                "_truncated": True,
+                                "_originalLength": len(content),
+                            }
+
+                    # Yield sanitized event for SSE streaming
+                    sse_event = ToolCallProgress.model_validate(sse_event_data)
+                    yield _serialize_acp_event(sse_event, "tool_call_progress")
 
                 elif isinstance(acp_event, AgentPlanUpdate):
                     event_data = acp_event.model_dump(