mvanhorn/last30days-skill · error · ValueError

Discovery supports listing sources only: reddit, hackernews,

Error message

Discovery supports listing sources only: reddit, hackernews, digg (unsupported: {', '.join(unsupported)})

What it means

Thrown by the shared discovery-sweep prologue in pipeline.py when the caller passes requested sources that are not listing sources. Discovery (run_discover / run_discover_nominate) only sweeps feed-style listing sources — reddit, hackernews, digg — because it works by listing recent feeds, not by keyword search. Any other source name (e.g. 'x', 'youtube', 'bluesky') is rejected up front before any network call.

Source

Thrown at skills/last30days/scripts/lib/pipeline.py:1062

    config: dict[str, Any],
    depth: str,
    requested_sources: list[str] | None,
    mock: bool,
    subreddits: list[str] | None,
    lookback_days: int,
    as_of_date: str | None,
) -> _DiscoverySweep:
    """Resolve the momentum window, validate/bound the listing sources, build
    the discovery plan, sweep the river feeds, and finalize source status.

    Shared verbatim by ``run_discover`` (one-shot) and
    ``run_discover_nominate`` (protocol leg 1) so the two paths can never
    drift on what a sweep means."""
    from_date, to_date = dates.get_date_range(lookback_days, as_of_date=as_of_date)
    requested = normalize_requested_sources(requested_sources)
    unsupported = sorted(set(requested or []) - set(DISCOVERY_SOURCES))
    if unsupported:
        raise ValueError(
            "Discovery supports listing sources only: reddit, hackernews, digg "
            f"(unsupported: {', '.join(unsupported)})"
        )
    available = list(DISCOVERY_SOURCES) if mock else [
        source for source in available_sources(config, requested, x_pending=False)
        if source in DISCOVERY_SOURCES
    ]
    if requested:
        available = [source for source in available if source in requested]
    plan = planner.build_discovery_plan(
        domain,
        available_sources=available,
        subreddits=subreddits,
    )

    global_mode = not plan.domain
    domain_label = plan.domain or "everything"
    query_plan = schema.QueryPlan(

View on GitHub (pinned to c7460f6114)

Solutions

1. Restrict requested_sources for discovery calls to subsets of ['reddit', 'hackernews', 'digg'].
2. If you want X/YouTube content, use the main research pipeline (run_pipeline), not discovery — discovery only nominates topics from listing feeds.
3. Filter the offending names before calling: [s for s in requested if s in {'reddit','hackernews','digg'}].
4. Check for typos/casing in the source names (normalize_requested_sources handles aliases, but non-existent sources still fail).

Example fix

# before
plan = run_discover(domain="ai agents", requested_sources=["reddit", "x", "youtube"])

# after
plan = run_discover(domain="ai agents", requested_sources=["reddit", "hackernews", "digg"])

DISCOVERY_SOURCES = {"reddit", "hackernews", "digg"}
requested = ["reddit", "x"]
bad = set(requested) - DISCOVERY_SOURCES
if bad:
    raise SystemExit(f"not valid for discovery: {sorted(bad)}")
requested = [s for s in requested if s in DISCOVERY_SOURCES] or list(DISCOVERY_SOURCES)

def is_discovery_source_list(sources: list[str]) -> bool:
    return bool(sources) and all(s in {"reddit", "hackernews", "digg"} for s in sources)

try:
    sweep = run_discover(domain, requested_sources=clean)
except ValueError as exc:
    if "unsupported" in str(exc):
        clean = [s for s in clean if s in DISCOVERY_SOURCES]
        sweep = run_discover(domain, requested_sources=clean)
    else:
        raise

When it happens

Trigger: Calling run_discover / run_discover_nominate (or the CLI discover path) with requested_sources containing names outside DISCOVERY_SOURCES, e.g. ['reddit', 'x'] or ['youtube']. The set difference of requested minus {reddit, hackernews, digg} is non-empty after normalize_requested_sources().

Common situations: Reusing a research-run source list (--sources reddit,x,youtube) for a discovery run; assuming discovery accepts the same source vocabulary as the main pipeline; typos in source names; a harness passing INCLUDE_SOURCES-style env values into discovery.

Related errors

• No listing sources are available for global trending
• No listing sources are available for {normalized_domain!r}
• Unknown search source in {flag_name}: {source}
• {flag_name} requires at least one source.
• subqueries[{index}].sources must be a non-empty string array

AI-assisted analysis of mvanhorn/last30days-skill@c7460f6114 (2026-08-15). Data as JSON: /api/errors/10a8779cbbb35630. Report an issue: GitHub.