diff --git a/src/lib/discipline/countdown-ignition.ts b/src/lib/discipline/countdown-ignition.ts
new file mode 100644
index 0000000..70ec9af
--- /dev/null
+++ b/src/lib/discipline/countdown-ignition.ts
@@ -0,0 +1,38 @@
+export type IgnitionState = 'COUNTING_DOWN' | 'ACTION_WINDOW' | 'EXPIRED';
+
+export interface IgnitionStatus {
+  state: IgnitionState;
+  secondsRemaining: number;
+  progressRatio: number; // 0.0 to 1.0
+}
+
+export function evaluateIgnitionCountdown(
+  elapsedMs: number,
+  countdownDurationMs: number = 5000,
+  actionWindowMs: number = 3000
+): IgnitionStatus {
+  const validElapsed = Math.max(0, elapsedMs);
+
+  if (validElapsed < countdownDurationMs) {
+    const remainingMs = countdownDurationMs - validElapsed;
+    return {
+      state: 'COUNTING_DOWN',
+      secondsRemaining: Math.ceil(remainingMs / 1000),
+      progressRatio: parseFloat((validElapsed / countdownDurationMs).toFixed(3)),
+    };
+  }
+
+  if (validElapsed <= countdownDurationMs + actionWindowMs) {
+    return {
+      state: 'ACTION_WINDOW',
+      secondsRemaining: 0,
+      progressRatio: 1.0,
+    };
+  }
+
+  return {
+    state: 'EXPIRED',
+    secondsRemaining: 0,
+    progressRatio: 1.0,
+  };
+}
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