Errors and rejects

OpenPit separates business rejects from API errors.

Business rejects

Policy rejects are expected outcomes. They are returned in result objects:

• StartResult.rejects

• ExecuteResult.rejects

• AccountAdjustmentBatchResult.rejects

Each reject contains a stable code, reason, details, policy name, scope, and an optional user_data token.

result = engine.execute_pre_trade(order=order)
if not result:
    for reject in result.rejects:
        print(reject.policy, reject.code, reject.reason)

Exceptions

Exceptions are reserved for invalid API usage or unexpected callback failures. Common cases include:

• TypeError for wrong wrapper types, such as raw int account IDs.

• ValueError for invalid domain values, such as empty assets.

• RuntimeError for lifecycle misuse, such as executing a request twice.

• RejectError for callback-level failures surfaced by the binding.

Do not raise exceptions for normal risk decisions in custom policies. Return PolicyReject or PolicyDecision.reject(...) instead.

AccountBlockError

Raised by the fallible admin account-blocking methods on engine.accounts(): replace_block_reason, block_group, unblock_group, and replace_group_block_reason.

AccountBlockError carries a human-readable error message indicating the failure reason (e.g., “account is not blocked”, “account group is not blocked”, “the reserved default account group is not a valid target”). The offending account or group identifier is not embedded in the message; read it from the error’s structured fields instead.

try:
    engine.accounts().replace_block_reason(account_id, "new reason")
except AccountBlockError as e:
    print(str(e))

AccountBlocked reject code

When a pre-trade order is submitted for an account that is currently blocked (directly or through its group), the engine rejects it with reject code RejectCode.ACCOUNT_BLOCKED. This reject is returned through the normal StartResult.rejects / ExecuteResult.rejects channel - it is not raised as an exception.