RC2_OVERRIDE_INVALID

Override kwarg (qty= or percent=) doesn’t match the sizing model.

What it means

Each sizing model accepts exactly one override kwarg, and rejects the other:

Sizing model	qty=	percent=
FixedQuantity	✅ Allowed	❌ RC2_OVERRIDE_INVALID
FixedCapital	❌ RC2_OVERRIDE_INVALID	✅ Allowed
Compounding	❌ RC2_OVERRIDE_INVALID	✅ Allowed

Why it happens

class Bad(Strategy):
    trade = Symbol()
    sizing = FixedCapital()

    def execute(self):
        if self.trade.is_flat:
            self.buy(self.trade, qty=100)   # ❌ qty= on FixedCapital

FixedCapital computes quantity from dollars and price. Override by adjusting the percentage; qty= doesn’t make sense in that model.

How to fix it

Match the kwarg to the sizing model:

class CapitalSized(Strategy):
    trade = Symbol()
    sizing = FixedCapital()

    def execute(self):
        if self.trade.is_flat:
            self.buy(self.trade, percent=50)        # ✅ 50% of initial capital

class QuantitySized(Strategy):
    trade = Symbol()
    sizing = FixedQuantity()

    def execute(self):
        if self.trade.is_flat:
            self.buy(self.trade, qty=100)           # ✅ 100 contracts

class CompoundSized(Strategy):
    trade = Symbol()
    sizing = Compounding()

    def execute(self):
        if self.trade.is_flat:
            self.buy(self.trade, percent=80)        # ✅ 80% of current equity

Or drop the override entirely and let the declared sizing model do the work:

class Declared(Strategy):
    trade = Symbol()
    sizing = FixedCapital(percent=80)

    def execute(self):
        if self.trade.is_flat:
            self.buy(self.trade)                    # ✅ 80%, as declared

percent= is always a replacement of the class-level setting, not multiplicative.

Related

• Sizing
• Order Verbs