linshenkx/prompt-optimizer · error · Error

Garden suggestions response must be an object

Error message

Garden suggestions response must be an object

What it means

Thrown by fetchPromptGardenSuggestions when the suggestions endpoint returns HTTP 200 but the JSON body is not an object (e.g. an array, string, number, or null). The library parses the body and runs an isRecord check before reading data.items; any non-object payload fails fast with this error instead of producing a TypeError later.

Source

Thrown at packages/ui/src/utils/prompt-garden-suggestions.ts:170

  const controller = new AbortController()
  const timeout = setTimeout(() => controller.abort(), options.timeoutMs ?? DEFAULT_TIMEOUT_MS)

  try {
    const resp = await fetch(url, {
      method: 'GET',
      headers: {
        Accept: 'application/json',
      },
      signal: controller.signal,
    })

    if (!resp.ok) {
      throw new Error(`Garden suggestions request failed: ${resp.status}`)
    }

    const data = (await resp.json()) as unknown
    if (!isRecord(data)) {
      throw new Error('Garden suggestions response must be an object')
    }

    const items = Array.isArray(data.items)
      ? data.items
          .map((item) => normalizeSuggestionItem(item, gardenBaseUrl))
          .filter((item): item is PromptGardenSuggestionItem => Boolean(item))
      : []

    const browseUrl =
      resolveGardenUrl(gardenBaseUrl, data.browseUrl) ||
      buildFallbackBrowseUrl(gardenBaseUrl, options.mode)

    const ttlSeconds =
      typeof data.ttlSeconds === 'number' && Number.isFinite(data.ttlSeconds) && data.ttlSeconds > 0
        ? Math.floor(data.ttlSeconds)
        : null

    return {

View on GitHub (pinned to 3e677b1d9f)

Solutions

1. Inspect the actual response body (curl the endpoint) to see the real shape
2. Upgrade/align the garden service and client versions so the response is { items: [...] }
3. Fix backend serialization to always return an object with items (possibly empty array)
4. Remove any proxy/rewrite rules that transform the response body

Example fix

// backend: return an object with items instead of a bare array
// before
return NextResponse.json(suggestions) // e.g. [{...}, {...}]
// after
return NextResponse.json({ items: suggestions })

const isSuggestionsResponse = (data: unknown): data is { items: unknown[] } =>
  typeof data === 'object' && data !== null && Array.isArray((data as { items?: unknown }).items)

try {
  const items = await fetchPromptGardenSuggestions(options)
} catch (error) {
  if ((error as Error).message.includes('must be an object')) {
    // endpoint/shape mismatch: log payload, fall back to empty suggestions
    return []
  }
  throw error
}

When it happens

Trigger: Endpoint returns a JSON array, bare string/number, or null body; a proxy or gateway returning a JSON-encoded error string with 200; misrouted endpoint returning a different JSON shape.

Common situations: API version mismatch where the deployed garden returns a list instead of { items: [...] }; middleware or CDN intercepting and rewriting responses; backend returning null for an empty result set.

Related errors

• INVALID_RESPONSE_FORMAT
• INVALID_RESPONSE_FORMAT
• INVALID_RESPONSE_FORMAT
• Unsupported Garden response schema
• Unsupported Garden response schemaVersion

AI-assisted analysis of linshenkx/prompt-optimizer@3e677b1d9f (2026-08-27). Data as JSON: /api/errors/96949f535211593b. Report an issue: GitHub.