Tencent/WeKnora · error

a message can use at most %d attachments

Error message

a message can use at most %d attachments

What it means

ResolveForPrompt enforces types.MaxTemporaryAttachmentsPerMessage as a hard cap on how many temporary documents may be attached to a single chat message. Exceeding the cap aborts before any document lookup.

Source

Thrown at internal/application/service/temporary_document.go:600

		out = append(out, ref.ImageData)
		if len(out) >= limit {
			break
		}
	}
	return out
}

// approxTextContentRunes counts the runes of real text in markdown, ignoring
// image references, so scanned/image-only documents register as low-text.
func approxTextContentRunes(md string) int {
	stripped := markdownImagePattern.ReplaceAllString(md, "")
	return len([]rune(strings.TrimSpace(stripped)))
}

func (s *temporaryDocumentService) ResolveForPrompt(ctx context.Context, tenantID uint64, sessionID string, documentIDs []string, query string) (*types.TemporaryDocumentPromptResult, error) {
	result := &types.TemporaryDocumentPromptResult{}
	if len(documentIDs) > types.MaxTemporaryAttachmentsPerMessage {
		return nil, fmt.Errorf("a message can use at most %d attachments", types.MaxTemporaryAttachmentsPerMessage)
	}
	perDocumentBudget := temporaryDocumentPromptBudget
	if len(documentIDs) > 0 {
		perDocumentBudget = temporaryDocumentPromptBudget / len(documentIDs)
	}
	seen := make(map[string]struct{}, len(documentIDs))
	for _, documentID := range documentIDs {
		if _, duplicate := seen[documentID]; duplicate {
			continue
		}
		seen[documentID] = struct{}{}
		document, err := s.repo.GetScoped(ctx, tenantID, sessionID, documentID)
		if err != nil {
			return nil, err
		}
		if document == nil {
			return nil, fmt.Errorf("attachment %s was not found in this session", documentID)
		}

View on GitHub (pinned to 988cbb0330)

Solutions

1. Limit the attachments selected to MaxTemporaryAttachmentsPerMessage before sending
2. Update the client UI to enforce the same cap at selection time
3. Split the content across multiple messages if more attachments are needed
4. Raise MaxTemporaryAttachmentsPerMessage consciously if the cap is genuinely too low

Example fix

// before
if len(documentIDs) > MaxTemporaryAttachmentsPerMessage { ... }
// after
if len(documentIDs) > MaxTemporaryAttachmentsPerMessage {
    documentIDs = documentIDs[:MaxTemporaryAttachmentsPerMessage]
}

if len(documentIDs) > types.MaxTemporaryAttachmentsPerMessage {
    return errors.New("too many attachments")
}

When it happens

Trigger: Calling ResolveForPrompt (via the chat/message send path) with a documentIDs slice longer than MaxTemporaryAttachmentsPerMessage.

Common situations: Client allows unlimited attachment selection in the UI; API consumer sends a large documentIDs array directly; batch message built from prior session references.

Related errors

• attachment exceeds the %d MiB limit
• attachment has no file extension
• invite code has expired
• join request not found
• failed to retrieve: %s

AI-assisted analysis of Tencent/WeKnora@988cbb0330 (2026-09-02). Data as JSON: /api/errors/ea57273b6ac21bcc. Report an issue: GitHub.