linshenkx/prompt-optimizer · error · Error

Empty prompt.messages

Error message

Empty prompt.messages

What it means

When format === 'messages', the prompt body's `messages` array is passed through normalizeImportedConversationMessages; if normalization yields zero messages, this error is thrown. Zero results can mean the input was empty or every entry failed normalization (bad role, invalid structure).

Solutions

1. Inspect prompt.messages and confirm each entry has a recognized role and valid content shape
2. Log which entries normalizeImportedConversationMessages drops to find the invalid message structure
3. Re-export with a conversation containing at least one valid user/assistant message

Example fix

// before
{ "prompt": { "format": "messages", "messages": [] } }

// after
{ "prompt": { "format": "messages", "messages": [ { "role": "user", "content": "Hello" } ] } }

const msgs = raw?.prompt?.messages
if (!Array.isArray(msgs) || msgs.length === 0) { /* block import */ }
// additionally check each entry has a known role

const isMessageArray = (v: unknown): v is Array<{ role: string; content: unknown }> =>
  Array.isArray(v) && v.length > 0 && v.every(m => isPlainObject(m) && typeof m.role === 'string')

catch (e) { if (e.message === 'Empty prompt.messages') showImportError('Conversation is empty or invalid'); else throw e }

When it happens

Trigger: prompt.messages is undefined/null/[] or contains only entries that normalizeImportedConversationMessages filters out (missing/invalid role or content).

Common situations: Messages exported with roles the importer doesn't recognize (e.g. 'tool', 'system2'); entries whose content is an unsupported shape; empty conversations exported as valid; upstream renamed 'role'/'content' keys.

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.

Related errors

• Empty prompt.text
• At least one message is required
• Each message must have role and content
• Invalid message role
• Iteration failed: Template not found or invalid

AI-assisted analysis of linshenkx/prompt-optimizer@3e677b1d9f (2026-08-27). Data as JSON: /api/errors/db98943d8b1c2b64. Report an issue: GitHub.

Appendix: source

Thrown at packages/ui/src/composables/app/useAppPromptGardenImport.ts:564

    const format = prompt && (prompt.format === 'text' || prompt.format === 'messages')
      ? (prompt.format as 'text' | 'messages')
      : null
    if (!format) {
      throw new Error('Missing prompt.format')
    }

    let promptText: string | undefined
    let promptMessages: ConversationMessage[] | undefined
    if (format === 'text') {
      const t = prompt && typeof prompt.text === 'string' ? prompt.text : ''
      if (!t.trim()) {
        throw new Error('Empty prompt.text')
      }
      promptText = t
    } else {
      const msgs = normalizeImportedConversationMessages(prompt?.messages)
      if (!msgs.length) {
        throw new Error('Empty prompt.messages')
      }
      promptMessages = msgs
    }

    if (!Array.isArray(data.variables)) {
      throw new Error('Missing variables')
    }
    const variablesForImport = data.variables
      .map((v): { name: string; defaultValue?: string } => {
        if (!isPlainObject(v)) return { name: '' }
        const name = typeof v.name === 'string' ? v.name.trim() : ''
        const defaultValue = typeof v.defaultValue === 'string' ? v.defaultValue : undefined
        return { name, defaultValue }
      })
      .filter((v) => isValidVariableName(v.name))

    const snapshotVariables = data.variables
      .map((v): GardenSnapshotVariable | null => {

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