What causes "operation %d: add requires title" in vxcontrol/pentagi?

Set a non-empty title on every add operation before calling Validate/applying the patch.

operation %d: add requires title

Error message

operation %d: add requires title

What it means

SubtaskPatch.Validate checks each SubtaskOperation in the patch. For op == SubtaskOpAdd, both Title and Description are mandatory; this error fires when Title is empty. It protects the task planner from creating unnamed subtasks via the patch_flow_subtasks tool.

Source

Thrown at backend/pkg/tools/args.go:323

type WaitFlowCompletionAction struct {
	Timeout Int64  `json:"timeout" jsonschema:"required,type=integer" jsonschema_description:"How long to wait for the running automation task to finish, in seconds. Use 0 or a negative value to apply the default timeout of 60 seconds. Values above 3600 are capped at 3600 seconds (1 hour)."`
	Message string `json:"message" jsonschema:"required,title=Wait message" jsonschema_description:"Engagement-log entry — a 1-2 short sentence running commentary explaining why you are waiting for the automation to finish. Written in the engagement language declared by your system prompt."`
}

// PatchFlowSubtasksAction defines arguments for the patch_flow_subtasks tool.
type PatchFlowSubtasksAction struct {
	TaskID     int64              `json:"task_id" jsonschema:"required,type=integer" jsonschema_description:"ID of the task whose subtask plan to modify. Obtain this from get_flow_status with detail='tasks'."`
	Operations []SubtaskOperation `json:"operations" jsonschema:"required" jsonschema_description:"Delta operations to apply: add (insert new subtask at a position), remove (delete by ID), modify (update title/description), reorder (move to different position). Empty array returns the current plan unchanged. Each operation's title/description, when present, is an engagement-log plan entry (see operations)."`
	Message    string             `json:"message" jsonschema:"required,title=Patch summary" jsonschema_description:"Engagement-log entry — a 1-2 short sentence running commentary describing what changes are being made to the plan. Written in the engagement language declared by your system prompt."`
}

// ValidateSubtaskPatch validates the operations in a SubtaskPatch
func (sp SubtaskPatch) Validate() error {
	for i, op := range sp.Operations {
		switch op.Op {
		case SubtaskOpAdd:
			if op.Title == "" {
				return fmt.Errorf("operation %d: add requires title", i)
			}
			if op.Description == "" {
				return fmt.Errorf("operation %d: add requires description", i)
			}
		case SubtaskOpRemove:
			if op.ID == nil {
				return fmt.Errorf("operation %d: remove requires id", i)
			}
		case SubtaskOpModify:
			if op.ID == nil {
				return fmt.Errorf("operation %d: modify requires id", i)
			}
			if op.Title == "" && op.Description == "" {
				return fmt.Errorf("operation %d: modify requires at least title or description", i)
			}
		case SubtaskOpReorder:
			if op.ID == nil {
				return fmt.Errorf("operation %d: reorder requires id", i)

View on GitHub (pinned to ea665308ba)

Solutions

Set a non-empty title on every add operation before calling Validate/applying the patch.
Pre-validate the operations array client-side and reject add ops missing title or description.
Tighten the tool's JSON schema description/prompt so the LLM always supplies both fields.

Example fix

// before
ops := []SubtaskOperation{{Op: SubtaskOpAdd, Description: "scan ports"}}
// after
ops := []SubtaskOperation{{Op: SubtaskOpAdd, Title: "Port scan", Description: "scan ports"}}

Defensive patterns

Strategy: validation

Validate before calling

for i, op := range ops {
    if op.Op == "add" && (op.Title == "" || op.Description == "") {
        return fmt.Errorf("op %d: add needs title and description", i)
    }
}

Type guard

func validAddOp(op SubtaskOperation) bool {
    return op.Op == SubtaskOpAdd && op.Title != "" && op.Description != ""
}

Try / catch

if err := patch.Validate(); err != nil {
    var idx int
    if _, scanErr := fmt.Sscanf(err.Error(), "operation %d:", &idx); scanErr == nil {
        // repair or drop operations[idx] and revalidate
    }
}

Prevention

Always emit both title and description for add operations in LLM tool prompts.
Pre-validate patches client-side before invoking patch_flow_subtasks.
Set jsonschema required fields so the model is constrained at generation time.
Drop malformed add ops instead of failing the whole patch when partial application is acceptable.

When it happens

Trigger: Submitting PatchFlowSubtasksAction with an operations entry {"op":"add"} (or op=add via SubtaskPatch) whose title field is empty or omitted; LLM tool call omitting title in an add operation.

Common situations: LLM agents generate add operations with only a description; JSON marshaling drops an empty title field; hand-written automation scripts building patches.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

AI-assisted analysis of vxcontrol/pentagi@ea665308ba (2026-09-01). Data as JSON: /api/errors/4d538fb374b8e48a. Report an issue: GitHub.