What causes "expected Polymarket BinaryOption instrument, found {instrument:?}" in nautechsystems/nautilus_trader?

Ensure the instrument for this condition_id was created as a Polymarket BinaryOption via the Polymarket instrument provider/factory.

nautechsystems/nautilus_trader · error

expected Polymarket BinaryOption instrument, found {instrume

Error message

expected Polymarket BinaryOption instrument, found {instrument:?}

What it means

validate_instrument_binding expects the instrument bound to a Polymarket condition to be a BinaryOption whose metadata carries condition_id and outcome info; if the caller passes any other InstrumentAny variant, it bails with a debug dump of what was actually found. It is an internal binding/type contract check during order-report and trade reconciliation.

Source

Thrown at crates/adapters/polymarket/src/execution/reconciliation.rs:244

        .with_context(|| format!("maker trade {} has invalid trade ID source", trade.id))?;
    let composite_trade_id = composite_trade_id_value(&trade.id, &maker_order.order_id);
    let trade_id = checked_trade_id(
        &composite_trade_id,
        &format!("maker trade {} composite", trade.id),
    )?;
    Ok(ValidatedMakerReportIdentifiers {
        venue_order_id,
        trade_id,
    })
}

fn validate_instrument_binding(
    instrument: &InstrumentAny,
    condition_id: &str,
    outcome: PolymarketOutcome,
) -> anyhow::Result<()> {
    let InstrumentAny::BinaryOption(binary) = instrument else {
        anyhow::bail!("expected Polymarket BinaryOption instrument, found {instrument:?}");
    };
    let instrument_condition = binary
        .info
        .as_ref()
        .and_then(|info| info.get_str("condition_id"))
        .context("Polymarket instrument is missing condition_id metadata")?;

    anyhow::ensure!(
        instrument_condition.eq_ignore_ascii_case(condition_id),
        "provider condition {condition_id} does not match instrument condition {instrument_condition}",
    );
    let instrument_outcome = binary
        .outcome
        .context("Polymarket instrument is missing outcome metadata")?;
    anyhow::ensure!(
        instrument_outcome == outcome.as_str(),
        "provider outcome {outcome} does not match instrument outcome {instrument_outcome}",
    );

View on GitHub (pinned to 18893faf8b)

Solutions

Ensure the instrument for this condition_id was created as a Polymarket BinaryOption via the Polymarket instrument provider/factory.
Check that reconciliation inputs come from Polymarket order/fill events, not another adapter's instrument cache.
Log/inspect the instrument debug output in the message to see which variant was actually passed and where it originated.
Add an up-front assert or filter that only BinaryOption instruments reach the Polymarket reconciliation path.

Example fix

// before
let report = build_order_report_from_order(&any_instrument, &order)?;
// after
if !matches!(any_instrument, InstrumentAny::BinaryOption(_)) {
    eprintln!("skipping non-BinaryOption instrument in Polymarket reconciliation");
    return Ok(None);
}
let report = build_order_report_from_order(&any_instrument, &order)?;

Defensive patterns

Strategy: type-guard

Validate before calling

let InstrumentAny::BinaryOption(binary) = instrument else {
    return Err(format!("Polymarket reconciliation requires BinaryOption, got {instrument:?}"));
};

Type guard

fn is_polymarket_binary(instrument: &InstrumentAny) -> bool {
    matches!(instrument, InstrumentAny::BinaryOption(_))
}

Prevention

Register instruments through the Polymarket provider so they are BinaryOption
Keep other venues' instruments out of the Polymarket reconciliation path
Check the instrument's condition_id metadata at registration time
Use matches!/let-else narrowing before any condition-specific logic

When it happens

Trigger: Calling build_order_report_from_order, classify_target_trade, or build_fill_reports_from_trades with an instrument registered as a non-BinaryOption type (e.g. a generic equity or crypto perpetual) that is not a Polymarket binary market, or with an incorrectly-registered instrument.

Common situations: Registering instruments with the wrong factory during adapter setup; feeding orders/fills from another venue into the Polymarket reconciliation path; a version change where instrument construction defaults changed.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/5f821271b9594254. Report an issue: GitHub.