What Bungie has documented
Bungie documented account-wide weekly bad-luck protection for Eyes of Tomorrow and said the design can eventually guarantee a drop. The article explains how weekly progress is shared across characters, but it does not disclose a percentage function that can be copied into a general raid calculator.
Read Bungie's Eyes of Tomorrow explanation.
What remains an input
- The base probability for the exact target and current patch.
- Whether prior failures change the next eligible attempt.
- The size and timing of any increase and whether a cap exists.
- Which completions are eligible under the current activity rotation and account state.
If a value cannot be sourced, use the calculator to explore it as a hypothetical scenario—not as a prediction of the hidden server-side rate.