The reflected-attack window (rules rev 25)

A FULL REFLECTION's returned spell is a fresh attack on its own caster —
who, per the owner's ruling, gets a defender's counteraction window
against it (absorb the blast, shield it, or FULL REFLECTION again: the
ping-pong war ends when the cards run out). The reflection now settles
into a new stack with the roles swapped and the damage pre-priced
(numbers, amplifies, and surviving counters already applied); the blow
returns to its sender unerringly, with no fresh hit rolls. onResolved
effects run with the swapped roles, so a reflected IDIOT now afflicts
its own caster. Earlier revisions land the blow instantly and stored
games replay unchanged.

Automatons price the incoming reflected damage off the stack; the attack
modal announces 'Your own spell comes screaming back!' with the inbound
total.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0138A8CjeQRpvzKxuMfz1Bqc

packages/engine/test/casting.test.ts

@@ -962,3 +962,64 @@ describe("empathy mirrors resolution-hook blows (rules rev 16)", () => {
     expect(15 - aAfter.life).toBe(15 - dAfter.life);
   });
 });
+
+describe("the reflected-attack window (rules rev 25)", () => {
+  function reflectRig() {
+    let { state } = createGame({ playerIds: ["a", "b"], seed: 42, sets: ["basic"], deckRev: 25 });
+    state = toRound2(state);
+    const { attacker, defender } = faceOff(state);
+    const sd = giveCard(state, attacker, "sudden-death");
+    giveCard(state, defender, "full-reflection", "FR", 0);
+    state = must(state, attacker, {
+      type: "cast", instanceId: sd.instanceId, target: { kind: "player", playerId: defender },
+    });
+    state = must(state, defender, { type: "counteract", instanceId: "full-reflection#FR" });
+    // The attacker's pass meets the total stop and settles the reflection —
+    // which opens the returned spell's window, waiting on the caster.
+    state = must(state, attacker, { type: "pass" });
+    return { state, attacker, defender };
+  }
+
+  it("the returned spell opens a window: absorb soaks the reflected blast", () => {
+    let { state, attacker, defender } = reflectRig();
+    // The reflection settled into a NEW stack: the caster now defends.
+    expect(state.stack).not.toBeNull();
+    expect(state.stack!.defenderId).toBe(attacker);
+    expect(state.stack!.reflectedBase).toEqual({ damage: 10, duration: 0 });
+    giveCard(state, attacker, "absorb", "AB", 0);
+    state = must(state, attacker, { type: "counteract", instanceId: "absorb#AB" });
+    state = must(state, defender, { type: "pass" });
+    state = must(state, attacker, { type: "pass" });
+    // 10 reflected minus absorb's 3.
+    expect(state.players.find((p) => p.id === attacker)!.life).toBe(8);
+    expect(state.players.find((p) => p.id === defender)!.life).toBe(15);
+  });
+
+  it("a second full reflection turns it around again — the ping-pong war", () => {
+    let { state, attacker, defender } = reflectRig();
+    giveCard(state, attacker, "full-reflection", "FR2", 0);
+    state = must(state, attacker, { type: "counteract", instanceId: "full-reflection#FR2" });
+    state = must(state, defender, { type: "pass" });
+    // Turned around again: now the original defender must answer it.
+    expect(state.stack).not.toBeNull();
+    expect(state.stack!.defenderId).toBe(defender);
+    state = must(state, defender, { type: "pass" });
+    expect(state.players.find((p) => p.id === defender)!.life).toBe(5);
+    expect(state.players.find((p) => p.id === attacker)!.life).toBe(15);
+  });
+
+  it("rev 24 lands the reflected blow instantly, as stored games replay", () => {
+    let { state } = createGame({ playerIds: ["a", "b"], seed: 42, sets: ["basic"], deckRev: 24 });
+    state = toRound2(state);
+    const { attacker, defender } = faceOff(state);
+    const sd = giveCard(state, attacker, "sudden-death");
+    giveCard(state, defender, "full-reflection", "FR", 0);
+    state = must(state, attacker, {
+      type: "cast", instanceId: sd.instanceId, target: { kind: "player", playerId: defender },
+    });
+    state = must(state, defender, { type: "counteract", instanceId: "full-reflection#FR" });
+    state = must(state, attacker, { type: "pass" });
+    expect(state.stack).toBeNull();
+    expect(state.players.find((p) => p.id === attacker)!.life).toBe(5);
+  });
+});