T08 iter 5: the DARVO sequence machine

Resolution step 3 (GR-R06), the last unimplemented step:

- GR-D02 binding: one stage per consecutive round, DENY then ATTACK
  then REVERSE, regardless of the player's later Stress.
- GR-D03 DENY: turn one face-up, unsolved, unprotected Problem face
  down and Deny it. Under the U3 default no legal target is a no-op and
  the sequence still advances.
- GR-D04 ATTACK: one extra Attack under the normal relation rules, then
  place the Focus token beside the target even if it was cancelled.
- GR-D05 REVERSE: flip Focus to Blame, +1 Stress to the holder, one
  Protection to the owner, unless the holder's GROUND-ND rejects it.
  Under the U5 default the owner takes -2 either way and the sequence
  ends.
- GR-D06 early end: a Support through a Bond that predates this round's
  Support step cancels the stage and ends the sequence, and the placed
  Focus token is removed. GROUND-GR ends it after the stage resolves.
- GR-D07: the marker returns to OFF, so a later End can re-trigger.

The Attack rules are now one routine shared by the chosen ATTACK Action
and the DARVO extra Attack, so GR-A06..A09 cannot drift between them.

Stage targets are named by their own command during Reveal, validated
against what the stage admits: DENY needs an eligible Problem, ATTACK
another player, and only a player with a live sequence may choose.

18 scenarios pass; AM-1 coverage 47/58 (81%), up from 41/58.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

games/ground/src/lib.rs

@@ -138,11 +138,22 @@ pub struct GroundState {
     pub ground_choices: BTreeMap<PlayerId, GroundChoice>,
     /// GR-L02/A05: a Support target's response, keyed by target.
     pub support_responses: BTreeMap<PlayerId, SupportResponse>,
+    /// GR-D03/D04: the mandatory target a DARVO stage needs this round.
+    pub darvo_targets: BTreeMap<PlayerId, DarvoTarget>,
     /// GR-S04/U4: retained so a deck reshuffle stays a pure function of
     /// state, keeping `validate` deterministic without holding RNG state.
     pub seed: u64,
 }
 
+/// GR-D03/D04: what a DARVO stage acts on this round. DENY names a
+/// Problem, ATTACK names a player; REVERSE takes its target from the
+/// Focus token placed by the ATTACK stage.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+pub struct DarvoTarget {
+    pub problem: Option<u32>,
+    pub player: Option<PlayerId>,
+}
+
 /// GR-A10..A12: the three GROUND modes.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
 pub enum GroundMode {
@@ -326,6 +337,8 @@ pub enum GroundCommand {
     },
     /// GR-L02/A05: respond to a Support aimed at this player.
     RespondToSupport { response: SupportResponse },
+    /// GR-D03/D04: name the mandatory target of this round's stage.
+    ChooseDarvoTarget { target: DarvoTarget },
     /// GR-R04: reveal all selections simultaneously. System-driven.
     Reveal,
     /// GR-R06/R07: resolve revealed Actions in fixed step order, Lead
@@ -425,6 +438,38 @@ pub enum GroundEvent {
     DarvoTriggered {
         player: PlayerId,
     },
+    /// GR-D03/D04.
+    DarvoTargetChosen {
+        player: PlayerId,
+        target: DarvoTarget,
+    },
+    /// GR-D03: a Problem was turned face down and Denied.
+    ProblemDenied {
+        problem: u32,
+    },
+    /// GR-D04/T03: the sequence owner's Focus token was placed.
+    FocusPlaced {
+        owner: PlayerId,
+        target: PlayerId,
+    },
+    /// GR-D05/T03: Focus flipped to Blame in front of the target.
+    FocusFlippedToBlame {
+        owner: PlayerId,
+        target: PlayerId,
+    },
+    /// GR-D05/T01.
+    ProtectionGained {
+        player: PlayerId,
+    },
+    /// GR-D02: the sequence moved to its next stage.
+    DarvoAdvanced {
+        player: PlayerId,
+        stage: DarvoStage,
+    },
+    /// GR-D05/D06/D07: the sequence ended and the marker is OFF again.
+    DarvoEnded {
+        player: PlayerId,
+    },
     /// GR-R01: the round advanced to `step`.
     StepAdvanced {
         step: RoundStep,
@@ -679,6 +724,64 @@ impl Aggregate for GroundState {
                     response: *response,
                 }])
             }
+            // GR-D03/D04: only a player with a live sequence, after
+            // Reveal, once per round.
+            GroundCommand::ChooseDarvoTarget { target } => {
+                if self.step != RoundStep::Reveal {
+                    return Err(Rejection::NotAllowedNow);
+                }
+                if player.darvo == DarvoStage::Off {
+                    return Err(Rejection::Game {
+                        code: "no-darvo-sequence".into(),
+                        detail: "GR-D02: this player has no live DARVO sequence".into(),
+                    });
+                }
+                if self.darvo_targets.contains_key(&id) {
+                    return Err(Rejection::DuplicateCommand);
+                }
+                match player.darvo {
+                    // GR-D03: a face-up, unsolved, unprotected Problem.
+                    DarvoStage::Deny => {
+                        let problem = target.problem.ok_or(Rejection::Game {
+                            code: "bad-darvo-target".into(),
+                            detail: "GR-D03: DENY names a Problem".into(),
+                        })?;
+                        let eligible = self.problems.get(&problem).is_some_and(|p| {
+                            p.face_up
+                                && !p.denied
+                                && p.claimed_by.is_none()
+                                && !p.protected_this_round
+                        });
+                        if !eligible {
+                            return Err(Rejection::Game {
+                                code: "bad-darvo-target".into(),
+                                detail: format!(
+                                    "GR-D03: Problem {problem} is not face-up, unsolved and unprotected"
+                                ),
+                            });
+                        }
+                    }
+                    // GR-D04: an extra Attack against another player.
+                    DarvoStage::Attack => {
+                        let other = target.player.ok_or(Rejection::Game {
+                            code: "bad-darvo-target".into(),
+                            detail: "GR-D04: ATTACK names a player".into(),
+                        })?;
+                        if other == id || !self.players.contains_key(&other) {
+                            return Err(Rejection::Game {
+                                code: "bad-darvo-target".into(),
+                                detail: "GR-D04: ATTACK targets another player".into(),
+                            });
+                        }
+                    }
+                    // GR-D05: REVERSE uses the placed Focus token.
+                    DarvoStage::Reverse | DarvoStage::Off => {}
+                }
+                Ok(vec![GroundEvent::DarvoTargetChosen {
+                    player: id,
+                    target: *target,
+                }])
+            }
             GroundCommand::Reveal | GroundCommand::Resolve | GroundCommand::EndRound => {
                 unreachable!("system commands are handled above")
             }
@@ -783,6 +886,41 @@ impl Aggregate for GroundState {
                     state.darvo = DarvoStage::Deny;
                 }
             }
+            GroundEvent::DarvoTargetChosen { player, target } => {
+                self.darvo_targets.insert(*player, *target);
+            }
+            GroundEvent::ProblemDenied { problem } => {
+                if let Some(state) = self.problems.get_mut(problem) {
+                    state.denied = true;
+                    state.face_up = false;
+                }
+            }
+            GroundEvent::FocusPlaced { owner, target } => {
+                self.focus.insert(*owner, *target);
+            }
+            GroundEvent::FocusFlippedToBlame { owner, target } => {
+                self.focus.remove(owner);
+                if let Some(state) = self.players.get_mut(target) {
+                    state.blame_from.push(*owner);
+                }
+            }
+            GroundEvent::ProtectionGained { player } => {
+                if let Some(state) = self.players.get_mut(player) {
+                    state.protection = state.protection.saturating_add(1);
+                }
+            }
+            GroundEvent::DarvoAdvanced { player, stage } => {
+                if let Some(state) = self.players.get_mut(player) {
+                    state.darvo = *stage;
+                }
+            }
+            GroundEvent::DarvoEnded { player } => {
+                if let Some(state) = self.players.get_mut(player) {
+                    state.darvo = DarvoStage::Off;
+                }
+                // GR-D06: an unresolved Focus token comes back.
+                self.focus.remove(player);
+            }
             GroundEvent::StepAdvanced { step } => {
                 self.step = *step;
             }
@@ -793,6 +931,7 @@ impl Aggregate for GroundState {
                 self.ground_modes.clear();
                 self.ground_choices.clear();
                 self.support_responses.clear();
+                self.darvo_targets.clear();
                 for state in self.players.values_mut() {
                     // GR-R03: the gate lift lasts one Select step only.
                     state.freedom_gate_lifted = false;
@@ -958,6 +1097,106 @@ impl GroundState {
             }
         }
 
+        // Step 3 — active DARVO stages (GR-D02..D07).
+        for owner in self.seat_order() {
+            let stage = work.players[&owner].darvo;
+            if stage == DarvoStage::Off {
+                continue;
+            }
+
+            // GR-D06 + GR-A04: a Support through a Bond that existed
+            // before this round's Support step cancels the current stage
+            // and ends the sequence (GR-L05).
+            let bond_support = self.selections.iter().any(|(seat, sel)| {
+                sel.action == Action::Support
+                    && sel.target == Some(owner)
+                    && pre_existing.get(&Pair::new(*seat, owner)) == Some(&Relation::Bond)
+            });
+            if bond_support {
+                events.push(GroundEvent::DarvoEnded { player: owner });
+                work.fold(events.last().expect("just pushed"));
+                continue;
+            }
+
+            match stage {
+                // GR-D03: turn one eligible Problem face down and Deny
+                // it. Under the U3 default, no legal target is a no-op
+                // and the sequence still advances.
+                DarvoStage::Deny => {
+                    if let Some(problem) = work.darvo_targets.get(&owner).and_then(|t| t.problem) {
+                        let eligible = work.problems.get(&problem).is_some_and(|p| {
+                            p.face_up
+                                && !p.denied
+                                && p.claimed_by.is_none()
+                                && !p.protected_this_round
+                        });
+                        if eligible {
+                            events.push(GroundEvent::ProblemDenied { problem });
+                            work.fold(events.last().expect("just pushed"));
+                        }
+                    }
+                }
+                // GR-D04: one extra Attack under the normal relation
+                // rules, then place the Focus token beside the target —
+                // even if the Attack was cancelled.
+                DarvoStage::Attack => {
+                    if let Some(target) = work.darvo_targets.get(&owner).and_then(|t| t.player) {
+                        work.resolve_attack(owner, target, &ou_cancels, &mut events);
+                        events.push(GroundEvent::FocusPlaced { owner, target });
+                        work.fold(events.last().expect("just pushed"));
+                    }
+                }
+                // GR-D05: targets the Focus holder.
+                DarvoStage::Reverse => {
+                    if let Some(target) = work.focus.get(&owner).copied() {
+                        // GR-A12: the target's GROUND—ND may reject it.
+                        let rejected =
+                            work.ground_choices.get(&target) == Some(&GroundChoice::RejectReverse);
+                        if !rejected {
+                            events.push(GroundEvent::FocusFlippedToBlame { owner, target });
+                            work.fold(events.last().expect("just pushed"));
+                            let stress = work.stress_after(target, 1);
+                            events.push(GroundEvent::StressSet {
+                                player: target,
+                                stress,
+                            });
+                            work.fold(events.last().expect("just pushed"));
+                            events.push(GroundEvent::ProtectionGained { player: owner });
+                            work.fold(events.last().expect("just pushed"));
+                        }
+                        // U5: rejected or not, the owner still takes −2
+                        // and the sequence ends.
+                        let stress = work.stress_after(owner, -2);
+                        events.push(GroundEvent::StressSet {
+                            player: owner,
+                            stress,
+                        });
+                        work.fold(events.last().expect("just pushed"));
+                    }
+                }
+                DarvoStage::Off => {}
+            }
+
+            // GR-A10 + GR-D06: GROUND—GR ends the sequence after the
+            // current stage resolves. GR-D05: REVERSE ends it anyway.
+            let ground_gr = work.ground_modes.get(&owner) == Some(&GroundMode::Gr);
+            if ground_gr || stage == DarvoStage::Reverse {
+                events.push(GroundEvent::DarvoEnded { player: owner });
+                work.fold(events.last().expect("just pushed"));
+            } else {
+                // GR-D02: one stage per consecutive round.
+                let next = match stage {
+                    DarvoStage::Deny => DarvoStage::Attack,
+                    _ => DarvoStage::Reverse,
+                };
+                events.push(GroundEvent::DarvoAdvanced {
+                    player: owner,
+                    stage: next,
+                });
+                work.fold(events.last().expect("just pushed"));
+            }
+        }
+
         // Step 5 — Attack (GR-A06..A09).
         for actor in self.seat_order() {
             let Some(selection) = self.selections.get(&actor) else {
@@ -970,67 +1209,7 @@ impl GroundState {
                 continue;
             };
 
-            // GR-A09 under the U8 default: a GROUND—OU cancellation is
-            // chosen at step 1 and applies first, so Protection is only
-            // consumed when it is what actually cancels.
-            if ou_cancels.contains(&(actor, target)) {
-                continue;
-            }
-            // GR-A09/T01: Protection absorbs the Attack entirely.
-            if work.players[&target].protection > 0 {
-                events.push(GroundEvent::AttackCancelled {
-                    attacker: actor,
-                    target,
-                });
-                work.fold(events.last().expect("just pushed"));
-                continue;
-            }
-
-            let pair = Pair::new(actor, target);
-            match work.relation_between(actor, target) {
-                // GR-A07: Attack through a Bond — +2 and the Bond flips.
-                Some(Relation::Bond) => {
-                    let stress = work.stress_after(target, 2);
-                    events.push(GroundEvent::StressSet {
-                        player: target,
-                        stress,
-                    });
-                    work.fold(events.last().expect("just pushed"));
-                    events.push(GroundEvent::RelationFormed {
-                        pair,
-                        relation: Relation::Rivalry,
-                    });
-                    work.fold(events.last().expect("just pushed"));
-                }
-                // GR-A08: Attack through a Rivalry — +2 and it breaks.
-                Some(Relation::Rivalry) => {
-                    let stress = work.stress_after(target, 2);
-                    events.push(GroundEvent::StressSet {
-                        player: target,
-                        stress,
-                    });
-                    work.fold(events.last().expect("just pushed"));
-                    events.push(GroundEvent::RelationBroken { pair });
-                    work.fold(events.last().expect("just pushed"));
-                }
-                // GR-A06: no relation — +1, and a Rivalry forms without
-                // consent if both endpoints have a slot (GR-L01/L03).
-                None => {
-                    let stress = work.stress_after(target, 1);
-                    events.push(GroundEvent::StressSet {
-                        player: target,
-                        stress,
-                    });
-                    work.fold(events.last().expect("just pushed"));
-                    if work.has_free_slot(actor) && work.has_free_slot(target) {
-                        events.push(GroundEvent::RelationFormed {
-                            pair,
-                            relation: Relation::Rivalry,
-                        });
-                        work.fold(events.last().expect("just pushed"));
-                    }
-                }
-            }
+            work.resolve_attack(actor, target, &ou_cancels, &mut events);
         }
 
         // Step 4 — INVESTIGATE (GR-A01).
@@ -1099,6 +1278,67 @@ impl GroundState {
         events
     }
 
+    /// GR-A06..A09: one Attack under the normal relation rules. Shared
+    /// by the chosen ATTACK Action (step 5) and the DARVO ATTACK stage's
+    /// extra Attack (GR-D04).
+    fn resolve_attack(
+        &mut self,
+        attacker: PlayerId,
+        target: PlayerId,
+        ou_cancels: &std::collections::BTreeSet<(PlayerId, PlayerId)>,
+        events: &mut Vec<GroundEvent>,
+    ) {
+        // GR-A09 under the U8 default: a GROUND—OU cancellation is
+        // chosen at step 1 and applies first, so Protection is only
+        // consumed when it is what actually cancels.
+        if ou_cancels.contains(&(attacker, target)) {
+            return;
+        }
+        // GR-A09/T01: Protection absorbs the Attack entirely.
+        if self.players[&target].protection > 0 {
+            events.push(GroundEvent::AttackCancelled { attacker, target });
+            self.fold(events.last().expect("just pushed"));
+            return;
+        }
+
+        let pair = Pair::new(attacker, target);
+        let (delta, after) = match self.relation_between(attacker, target) {
+            // GR-A07: through a Bond — +2 and the Bond flips.
+            Some(Relation::Bond) => (
+                2,
+                Some(GroundEvent::RelationFormed {
+                    pair,
+                    relation: Relation::Rivalry,
+                }),
+            ),
+            // GR-A08: through a Rivalry — +2 and it breaks.
+            Some(Relation::Rivalry) => (2, Some(GroundEvent::RelationBroken { pair })),
+            // GR-A06: no relation — +1, and a Rivalry forms without
+            // consent if both endpoints have a slot (GR-L01/L03).
+            None => {
+                let forms = self.has_free_slot(attacker) && self.has_free_slot(target);
+                (
+                    1,
+                    forms.then_some(GroundEvent::RelationFormed {
+                        pair,
+                        relation: Relation::Rivalry,
+                    }),
+                )
+            }
+        };
+
+        let stress = self.stress_after(target, delta);
+        events.push(GroundEvent::StressSet {
+            player: target,
+            stress,
+        });
+        self.fold(events.last().expect("just pushed"));
+        if let Some(event) = after {
+            events.push(event);
+            self.fold(events.last().expect("just pushed"));
+        }
+    }
+
     /// GR-A01: draw one Solution, reshuffling the discard first if the
     /// deck is empty (the U4 default). The reshuffled order travels in
     /// the event so replay never re-derives it.
@@ -1367,6 +1607,7 @@ impl ScenarioGame for GroundState {
             ground_modes: BTreeMap::new(),
             ground_choices: BTreeMap::new(),
             support_responses: BTreeMap::new(),
+            darvo_targets: BTreeMap::new(),
             seed,
         })
     }
@@ -1408,6 +1649,18 @@ impl ScenarioGame for GroundState {
                     None => None,
                 },
             },
+            "choose_darvo_target" => GroundCommand::ChooseDarvoTarget {
+                target: DarvoTarget {
+                    problem: arg_u64("problem").map(|p| p as u32),
+                    player: match step.args.get("target") {
+                        Some(_) => match parse_actor(&arg_str("target")?)? {
+                            Actor::Player(seat) => Some(seat),
+                            Actor::System => return Err("target may not be SYSTEM".into()),
+                        },
+                        None => None,
+                    },
+                },
+            },
             "respond_to_support" => GroundCommand::RespondToSupport {
                 response: SupportResponse::parse(&arg_str("response")?)?,
             },
@@ -1455,6 +1708,7 @@ mod tests {
             ground_modes: BTreeMap::new(),
             ground_choices: BTreeMap::new(),
             support_responses: BTreeMap::new(),
+            darvo_targets: BTreeMap::new(),
             seed: 0,
         }
     }

scenarios/ground/gr-d03-darvo-deny.yaml

@@ -0,0 +1,48 @@
+scenario: ground/gr-d03-darvo-deny
+description: >
+  The DENY stage turns one face-up, unsolved, unprotected Problem face
+  down and Denies it (GR-D03), then the sequence advances to ATTACK
+  (GR-D02). A protected Problem is not a legal DENY target (GR-A11).
+covers: [GR-D02, GR-D03, GR-P01]
+provisional: false
+seed: 42
+setup:
+  players: 3
+  preset: standard-3p
+  patch:
+    "lead": 0
+    "players.0.darvo": Deny
+    "problems.2.face_up": true
+commands:
+  - actor: P1
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: P2
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: P3
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: SYSTEM
+    cmd: reveal
+  # GR-D02: only a player with a live sequence names a stage target.
+  - actor: P2
+    cmd: choose_darvo_target
+    args: { problem: 1 }
+  - actor: P1
+    cmd: choose_darvo_target
+    args: { problem: 1 }
+  - actor: SYSTEM
+    cmd: resolve
+expect:
+  events:
+    - kind: ProblemDenied
+      problem: 1
+    - kind: DarvoAdvanced
+      player: 0
+      stage: Attack
+  state:
+    "problems.1.denied": true
+    "problems.1.face_up": false
+    "players.0.darvo": Attack
+  rejects: [4]

scenarios/ground/gr-d04-darvo-attack.yaml

@@ -0,0 +1,53 @@
+scenario: ground/gr-d04-darvo-attack
+description: >
+  The ATTACK stage makes one extra Attack under the normal relation
+  rules and places the Focus token beside the target (GR-D04), then
+  advances to REVERSE.
+covers: [GR-D04, GR-T03]
+provisional: false
+seed: 42
+setup:
+  players: 3
+  preset: standard-3p
+  patch:
+    "lead": 0
+    "players.0.darvo": Attack
+commands:
+  - actor: P1
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: P2
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: P3
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: SYSTEM
+    cmd: reveal
+  # GR-D04: the extra Attack targets another player.
+  - actor: P1
+    cmd: choose_darvo_target
+    args: { target: P1 }
+  - actor: P1
+    cmd: choose_darvo_target
+    args: { target: P2 }
+  - actor: SYSTEM
+    cmd: resolve
+expect:
+  events:
+    - kind: StressSet
+      player: 1
+      stress: 3
+    - kind: FocusPlaced
+      owner: 0
+      target: 1
+    - kind: DarvoAdvanced
+      player: 0
+      stage: Reverse
+  state:
+    "players.1.stress": 3
+    "focus.0": 1
+    "players.0.darvo": Reverse
+    # GR-L03: the extra Attack forms a Rivalry like any other.
+    "relations.0-1": Rivalry
+  rejects: [4]

scenarios/ground/gr-d05-darvo-reverse.yaml

@@ -0,0 +1,54 @@
+scenario: ground/gr-d05-darvo-reverse
+description: >
+  The REVERSE stage flips Focus to Blame in front of the Focus holder,
+  gives them +1 Stress and the owner one Protection token, then the
+  owner takes −2 Stress and the sequence ends (GR-D05, GR-D07).
+covers: [GR-D05, GR-D07, GR-T01]
+provisional: true
+seed: 42
+setup:
+  players: 3
+  preset: standard-3p
+  patch:
+    "lead": 0
+    "players.0.darvo": Reverse
+    "players.0.stress": 3
+    "focus.0": 1
+commands:
+  - actor: P1
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: P2
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: P3
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: SYSTEM
+    cmd: reveal
+  - actor: SYSTEM
+    cmd: resolve
+expect:
+  events:
+    - kind: FocusFlippedToBlame
+      owner: 0
+      target: 1
+    - kind: StressSet
+      player: 1
+      stress: 3
+    - kind: ProtectionGained
+      player: 0
+    - kind: StressSet
+      player: 0
+      stress: 1
+    - kind: DarvoEnded
+      player: 0
+  state:
+    "players.1.blame_from": [0]
+    "players.1.stress": 3
+    "players.0.protection": 1
+    "players.0.stress": 1
+    # GR-D07: the marker is OFF, so a new sequence can trigger later.
+    "players.0.darvo": Off
+    "focus": {}
+  rejects: []

scenarios/ground/gr-d06-darvo-early-end.yaml

@@ -0,0 +1,43 @@
+scenario: ground/gr-d06-darvo-early-end
+description: >
+  A Support through a Bond that existed before this round cancels the
+  current stage and ends the sequence; the placed Focus token is removed
+  (GR-D06, GR-A04, GR-L05).
+covers: [GR-D06, GR-L05]
+provisional: false
+seed: 42
+setup:
+  players: 3
+  preset: standard-3p
+  patch:
+    "lead": 0
+    "players.0.darvo": Attack
+    "focus.0": 2
+    "relations.0-1": Bond
+commands:
+  - actor: P2
+    cmd: select_action
+    args: { action: SUPPORT, target: P1 }
+  - actor: P1
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: P3
+    cmd: select_action
+    args: { action: INVESTIGATE, problem: 3 }
+  - actor: SYSTEM
+    cmd: reveal
+  - actor: P1
+    cmd: choose_darvo_target
+    args: { target: P3 }
+  - actor: SYSTEM
+    cmd: resolve
+expect:
+  events:
+    - kind: DarvoEnded
+      player: 0
+  state:
+    "players.0.darvo": Off
+    # GR-D06: the stage never fired, so P3 took no extra Attack.
+    "players.2.stress": 2
+    "focus": {}
+  rejects: []