HKUDS/Vibe-Trading · error · TypeError

'title' must be a string

Error message

'title' must be a string

What it means

Raised by Job from_dict (agent/src/scheduled_research/models.py:478) when the optional 'title' field (default '') is present but is not a string. Titles are display metadata; any non-str value such as a number or list fails. The default when absent is the empty string, which passes.

Source

Thrown at agent/src/scheduled_research/models.py:478

        # one job to UTC — the semantics it had before the field existed —
        # instead of taking every other job down with it. Absent, blank, and
        # non-string values all normalize to None.
        raw_tz = data.get("timezone")
        tz = raw_tz if isinstance(raw_tz, str) and raw_tz.strip() else None
        if raw_tz is not None and tz is None:
            logger.warning(
                "scheduled research job %s has an unusable timezone %r; "
                "evaluating its schedule in UTC",
                job_id,
                raw_tz,
            )
        status = JobStatus(data["status"])
        title = data.get("title", "")
        source_type = data.get("source_type", "prompt")
        playbook_slug = data.get("playbook_slug")
        end_at = data.get("end_at")
        if not isinstance(title, str):
            raise TypeError("'title' must be a string")
        if source_type not in {"prompt", "playbook"}:
            raise ValueError("'source_type' must be 'prompt' or 'playbook'")
        if playbook_slug is not None and not isinstance(playbook_slug, str):
            raise TypeError("'playbook_slug' must be a string or null")
        if end_at is not None and (isinstance(end_at, bool) or not isinstance(end_at, int)):
            raise TypeError("'end_at' must be an integer (epoch ms) or null")
        raw_config = data.get("config")
        config: Dict[str, Any] = raw_config if isinstance(raw_config, dict) else {}
        delivery_channel = data.get("delivery_channel")
        delivery_target = data.get("delivery_target")
        delivery_target_ref = data.get("delivery_target_ref")
        delivery_target_label = data.get("delivery_target_label")
        for name, value in (
            ("delivery_channel", delivery_channel),
            ("delivery_target", delivery_target),
            ("delivery_target_ref", delivery_target_ref),
            ("delivery_target_label", delivery_target_label),
        ):

View on GitHub (pinned to 80ffdda44c)

Solutions

1. Coerce to str: str(title) when building the record
2. Validate user-supplied titles as strings at your API boundary
3. Omit the field if no title

Example fix

// before
record["title"] = run_count

// after
record["title"] = f"Run #{run_count}"

def title_ok(d):
    v = d.get("title", "")
    return isinstance(v, str)

def safe_title(v, default=""):
    return v if isinstance(v, str) else default

try:
    job = Job.from_dict(record)
except TypeError as exc:
    if "title" in str(exc):
        record = dict(record); record["title"] = str(record.get("title", ""))
        job = Job.from_dict(record)
    else:
        raise

When it happens

Trigger: {"title": 123} or {"title": ["Morning", "Digest"]}; absent key is fine because of the '' default.

Common situations: Titles derived from user numeric input or template lists; API layers that pass through untyped JSON bodies.

Related errors

• 'delivery' must be an object or null
• 'delivery.{name}' must be a string or null
• 'delivery.attempts' must be a non-negative integer
• 'id', 'prompt', and 'schedule' must be strings
• 'consecutive_failures' must be a non-negative integer

AI-assisted analysis of HKUDS/Vibe-Trading@80ffdda44c (2026-08-28). Data as JSON: /api/errors/a3d164fbd141999f. Report an issue: GitHub.