mem0ai/mem0 · error · ValueError

Invalid query: cannot be empty or whitespace-only.

Error message

Invalid query: cannot be empty or whitespace-only.

What it means

Raised by _validate_and_trim_search_query when the query is a string but contains only whitespace after .strip() (e.g. '', ' ', '\n\t'). An empty query would produce a meaningless embedding, so the SDK rejects it up front. Note the helper also trims the query, so valid queries are normalized to stripped text before embedding.

Source

Thrown at mem0/memory/main.py:250

            raise ValueError("top_k must be a valid integer")
        if top_k < 0:
            raise ValueError(
                f"Invalid top_k: {top_k}. Must be a non-negative integer."
            )


def _validate_and_trim_search_query(query: str) -> str:
    """
    Validates and normalizes a search query before embedding/vector search.

    Raises:
        ValueError: If query is not a string or is empty/whitespace-only.
    """
    if not isinstance(query, str):
        raise ValueError("Invalid query: must be a non-empty string.")
    trimmed = query.strip()
    if not trimmed:
        raise ValueError("Invalid query: cannot be empty or whitespace-only.")
    return trimmed


def _is_sensitive_field(field_name: str) -> bool:
    """Check if a field should be redacted for telemetry safety.

    Uses a layered approach:
    1. Runtime fields (allowlist) — always preserved, highest priority.
    2. Exact deny list — known secret field names.
    3. Suffix deny list — catches patterns like db_password, auth_secret, etc.
    """
    name = field_name.lower().strip()
    if name in _RUNTIME_FIELDS:
        return False
    if name in _SENSITIVE_FIELDS_EXACT:
        return True
    return any(name.endswith(suffix) for suffix in _SENSITIVE_SUFFIXES)

View on GitHub (pinned to 001c235229)

Solutions

1. Check query.strip() in your UI/wrapper before calling search and treat it as a no-op.
2. Fall back to a default retrieval query (e.g. last user message) when the computed query is blank.
3. Trim inputs at ingest time so stored/derived text is never whitespace-only.
4. Return an empty result list yourself instead of relying on the exception.

Example fix

# before
results = m.search(raw_input, filters=f)  # raw_input = "   "

# after
q = (raw_input or "").strip()
results = m.search(q, filters=f) if q else []

q = (query or "").strip()
if not q:
    return []  # or raise your own domain error
results = m.search(q, filters=f)

def is_searchable_query(q) -> bool:
    return isinstance(q, str) and len(q.strip()) > 0

When it happens

Trigger: m.search('', filters=...); m.search(' ', ...); a query built by string formatting where a variable was empty: f"{prefix} {suffix}" with both empty; user pressing Enter on an empty chat input that is forwarded directly; whitespace-only text extracted from a document chunk.

Common situations: Chat/RAG frontends forwarding empty user input; PDF/web scrapers yielding whitespace-only chunks that get searched; f-string templates with optional parts all empty.

Related errors

• Invalid query: must be a non-empty string.
• Cannot process an empty messages payload.
• At least one of text, metadata, timestamp, or expirationDate
• threshold must be a valid number
• Invalid threshold: ${threshold}. Must be between 0 and 1 (in

AI-assisted analysis of mem0ai/mem0@001c235229 (2026-08-15). Data as JSON: /api/errors/7c3b4a8cd63c8069. Report an issue: GitHub.