Bridge prevention-cost prompt accepted Clash of Wills tax but target spell was still countered #37

New Issue

bstein · 2026-07-11T22:25:27Z

bstein commented

2026-07-11 22:25:27 +00:00

What happened

In the deployed 0.6.28 Lazav v26 vs Emet-Selch proof game, player B cast Clash of Wills for X=1 targeting player A's Petty Theft. Player A then selected prevention_cost:yes (Pay prevention cost for Clash of Wills: {X}), and the model rationale says it paid the Clash tax to preserve Petty Theft. The next state still put Brazen Borrower/Petty Theft into player A's graveyard and Clash of Wills into player B's graveyard, while Emet-Selch stayed on the battlefield. This makes the accepted pay-tax action ineffective or misleading.

What should have happened

If the target spell's controller can pay X and chooses to pay, Veles/Forge should actually collect the required mana and let Petty Theft resolve. If the controller cannot pay, Veles should not present prevention_cost:yes as a legal action, or should fail closed/report that the payment attempt failed instead of logging a successful pay-tax rationale.

Context

evidence: Replay event 66 chose ability:181:0:x:1:stack_targets:15:0 (Clash of Wills ... (X=1) -> targets Petty Theft). Replay event 67 paid Clash with Island as U and Swamp as B. Replay event 68 chose prevention_cost:yes; the engine delta then added Brazen Borrower to player A graveyard and Clash of Wills to player B graveyard. Replay event 69 still shows Emet-Selch on player B battlefield.
feedback issue key: explicit:bridge prevention cost yes accepted without preserving unlessed spell
game log: /data/veles-artifacts/logs/dashboard/sp0628-emet-s686346007-v26-tournament/duel_commander_emet_selch_unsundered__1_g1_686346007/game.jsonl
root cause: bridge/prevention-cost unless payment resolution
run group: sp0628-emet-s686346007-v26-tournament
table url: https://veles.bstein.dev/table?path=/data/veles-artifacts/logs/dashboard/sp0628-emet-s686346007-v26-tournament/duel_commander_emet_selch_unsundered__1_g1_686346007/game.jsonl

## What happened In the deployed 0.6.28 Lazav v26 vs Emet-Selch proof game, player B cast Clash of Wills for X=1 targeting player A's Petty Theft. Player A then selected `prevention_cost:yes` (`Pay prevention cost for Clash of Wills: {X}`), and the model rationale says it paid the Clash tax to preserve Petty Theft. The next state still put Brazen Borrower/Petty Theft into player A's graveyard and Clash of Wills into player B's graveyard, while Emet-Selch stayed on the battlefield. This makes the accepted pay-tax action ineffective or misleading. ## What should have happened If the target spell's controller can pay X and chooses to pay, Veles/Forge should actually collect the required mana and let Petty Theft resolve. If the controller cannot pay, Veles should not present `prevention_cost:yes` as a legal action, or should fail closed/report that the payment attempt failed instead of logging a successful pay-tax rationale. ## Category - kind: bridge - severity: obvious ## Context - evidence: Replay event 66 chose `ability:181:0:x:1:stack_targets:15:0` (`Clash of Wills ... (X=1) -> targets Petty Theft`). Replay event 67 paid Clash with Island as U and Swamp as B. Replay event 68 chose `prevention_cost:yes`; the engine delta then added Brazen Borrower to player A graveyard and Clash of Wills to player B graveyard. Replay event 69 still shows Emet-Selch on player B battlefield. - feedback issue key: explicit:bridge prevention cost yes accepted without preserving unlessed spell - game log: /data/veles-artifacts/logs/dashboard/sp0628-emet-s686346007-v26-tournament/duel_commander_emet_selch_unsundered__1_g1_686346007/game.jsonl - root cause: bridge/prevention-cost unless payment resolution - run group: sp0628-emet-s686346007-v26-tournament - table url: https://veles.bstein.dev/table?path=/data/veles-artifacts/logs/dashboard/sp0628-emet-s686346007-v26-tournament/duel_commander_emet_selch_unsundered__1_g1_686346007/game.jsonl

bstein added the

kind/bridge

severity/obvious

format/duel-commander

labels 2026-07-11 22:25:28 +00:00

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Reference: cassandra-alpha/feedback#37