chenhg5/cc-connect · error

message or attachment is required

Error message

message or attachment is required

What it means

This error is returned by the Engine's session-send path when a send request is issued with an empty message body and no image or file attachments. The engine refuses to dispatch a completely empty outgoing message because platforms require at least one of text, images, or files to render a reply.

Source

Thrown at core/engine.go:11192

func (e *Engine) SendToSessionWithOptions(sessionKey, message string, images []ImageAttachment, files []FileAttachment, opts SendOptions) error {
	if strings.TrimSpace(opts.WorkDir) != "" {
		workDir, useWorkDirSession, err := e.resolveSendWorkDir(opts.WorkDir)
		if err != nil {
			return err
		}
		if useWorkDirSession {
			return e.SendToSessionInWorkDir(sessionKey, message, images, files, workDir, opts.AtUsers, opts.AtAll)
		}
	}

	state, p, replyCtx, err := e.resolveOutboundSessionTarget(sessionKey, len(images) > 0 || len(files) > 0)
	if err != nil {
		return err
	}

	if message == "" && len(images) == 0 && len(files) == 0 {
		return fmt.Errorf("message or attachment is required")
	}
	if (len(images) > 0 || len(files) > 0) && !e.attachmentSendEnabled {
		return ErrAttachmentSendDisabled
	}

	var imageSender ImageSender
	if len(images) > 0 {
		var ok bool
		imageSender, ok = p.(ImageSender)
		if !ok {
			return fmt.Errorf("platform %s: %w", p.Name(), ErrNotSupported)
		}
	}

	var fileSender FileSender
	if len(files) > 0 {
		var ok bool
		fileSender, ok = p.(FileSender)

View on GitHub (pinned to 4000b2338a)

Solutions

1. Ensure at least one of message text, images, or files is non-empty before calling the send API
2. Trim-check the message: if strings.TrimSpace(message)=="" && len(images)==0 && len(files)==0, abort or substitute placeholder text
3. If the intent was attachment-only, verify the attachment list was actually populated (file read succeeded)

Example fix

// before
engine.SendToSession(key, msg, nil, nil, "", nil, false)
// after
if strings.TrimSpace(msg) == "" && len(imgs) == 0 && len(files) == 0 {
    return fmt.Errorf("nothing to send")
}
engine.SendToSession(key, msg, imgs, files, "", nil, false)

if strings.TrimSpace(message) == "" && len(images) == 0 && len(files) == 0 {
    return fmt.Errorf("refusing to send: empty message and no attachments")
}

When it happens

Trigger: Calling the engine's send-to-session API (the one at core/engine.go that calls resolveOutboundSessionTarget) with message="", images=nil, files=nil — e.g. building the message from a variable that turned out empty, or trimming whitespace from the text before calling.

Common situations: Automation scripts that pass a shell variable which is empty; templates where all fields were optional and none were filled; callers that intended to send only an attachment but the attachment slice failed to populate.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

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AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/a6d9d43edb25891a. Report an issue: GitHub.