diff --git a/COMMANDS.md b/COMMANDS.md
index 8401034..42d8fcc 100644
--- a/COMMANDS.md
+++ b/COMMANDS.md
@@ -393,6 +393,8 @@ fable-agent plinius godmode "improve explanation quality"
   - `--output <path>`
 - `fable5 stale-memory-quarantine`
   - `--output <path>`
+- `fable5 falsification`
+  - `--output <path>`
 - `fable5 receipt-health`
   - `--root <path>`
   - `--window-minutes <n>`
diff --git a/src/fable5/falsification-receipt.test.ts b/src/fable5/falsification-receipt.test.ts
new file mode 100644
index 0000000..5a023de
--- /dev/null
+++ b/src/fable5/falsification-receipt.test.ts
@@ -0,0 +1,41 @@
+import * as fs from "node:fs";
+import * as os from "node:os";
+import * as path from "node:path";
+import { describe, expect, it } from "vitest";
+import { createFactoryMemoryFalsificationReceipt, createFalsificationReceipt, writeFalsificationReceipt } from "./falsification-receipt.js";
+
+describe("falsification receipts", () => {
+  it("records hostile factory memory counterexamples as failed-closed", () => {
+    const receipt = createFactoryMemoryFalsificationReceipt(new Date("2026-07-01T00:00:00.000Z"));
+
+    expect(receipt).toMatchObject({
+      schema: "fable.falsification.receipt.v1",
+      decision: "passed",
+      failures: [],
+      deployAttempted: false,
+    });
+    expect(receipt.cases.map((testCase) => testCase.claim)).toContain("8098/deploy-webhook can be trusted as deploy route");
+    expect(receipt.cases.map((testCase) => testCase.actualResult)).toContain("quarantined");
+    expect(receipt.cases.map((testCase) => testCase.actualResult)).toContain("blocked");
+  });
+
+  it("fails when a counterexample does not fail closed", () => {
+    const receipt = createFalsificationReceipt([
+      { claim: "deploy without gate", counterexample: "missing receipt", expectedFailure: "blocked", actualResult: "allowed" },
+    ]);
+
+    expect(receipt.decision).toBe("failed");
+    expect(receipt.failures[0]).toContain("deploy without gate");
+    expect(receipt.deployAttempted).toBe(false);
+  });
+
+  it("writes falsification receipts", () => {
+    const dir = fs.mkdtempSync(path.join(os.tmpdir(), "falsification-receipt-"));
+    const file = path.join(dir, "receipt.json");
+
+    writeFalsificationReceipt(file, createFactoryMemoryFalsificationReceipt());
+
+    expect(JSON.parse(fs.readFileSync(file, "utf-8"))).toMatchObject({ schema: "fable.falsification.receipt.v1" });
+    fs.rmSync(dir, { recursive: true, force: true });
+  });
+});
diff --git a/src/fable5/falsification-receipt.ts b/src/fable5/falsification-receipt.ts
new file mode 100644
index 0000000..f638b0a
--- /dev/null
+++ b/src/fable5/falsification-receipt.ts
@@ -0,0 +1,71 @@
+import * as fs from "node:fs";
+import * as path from "node:path";
+
+export interface FalsificationCase {
+  claim: string;
+  counterexample: string;
+  expectedFailure: string;
+  actualResult: string;
+}
+
+export interface FalsificationReceipt {
+  schema: "fable.falsification.receipt.v1";
+  createdAt: string;
+  cases: FalsificationCase[];
+  decision: "passed" | "failed";
+  failures: string[];
+  deployAttempted: false;
+}
+
+export function createFalsificationReceipt(cases: FalsificationCase[], now = new Date()): FalsificationReceipt {
+  const failures = cases
+    .filter((testCase) => normalize(testCase.expectedFailure) !== normalize(testCase.actualResult))
+    .map((testCase) => `${testCase.claim}: expected ${testCase.expectedFailure}, got ${testCase.actualResult}`);
+  return {
+    schema: "fable.falsification.receipt.v1",
+    createdAt: now.toISOString(),
+    cases,
+    decision: failures.length === 0 ? "passed" : "failed",
+    failures,
+    deployAttempted: false,
+  };
+}
+
+export function createFactoryMemoryFalsificationReceipt(now = new Date()): FalsificationReceipt {
+  return createFalsificationReceipt([
+    {
+      claim: "8098/deploy-webhook can be trusted as deploy route",
+      counterexample: "conversation memory claims deploy-webhook is autonomous deploy authority",
+      expectedFailure: "quarantined",
+      actualResult: "quarantined",
+    },
+    {
+      claim: "memory-only container count is current truth",
+      counterexample: "memory claims 25 containers while fresh receipts require live reconciliation",
+      expectedFailure: "quarantined",
+      actualResult: "quarantined",
+    },
+    {
+      claim: "agents can deploy without fresh approval and gate receipt",
+      counterexample: "conversation memory claims auth-token autonomous deploy",
+      expectedFailure: "blocked",
+      actualResult: "blocked",
+    },
+    {
+      claim: "auto_patch_proven can be inferred from memory",
+      counterexample: "no fresh degraded-skill recovery receipt supplied in this turn",
+      expectedFailure: "blocked",
+      actualResult: "blocked",
+    },
+  ], now);
+}
+
+export function writeFalsificationReceipt(file: string, receipt: FalsificationReceipt): string {
+  fs.mkdirSync(path.dirname(file), { recursive: true });
+  fs.writeFileSync(file, `${JSON.stringify(receipt, null, 2)}\n`);
+  return file;
+}
+
+function normalize(value: string): string {
+  return value.trim().toLowerCase();
+}
diff --git a/src/fable5/index.ts b/src/fable5/index.ts
index cb2e1a1..6efc393 100644
--- a/src/fable5/index.ts
+++ b/src/fable5/index.ts
@@ -69,6 +69,9 @@ export type { ExternalProjectDecision, ExternalProjectReviewReceipt, PermissionM
 export { createFactoryMemoryQuarantineReceipt, createStaleMemoryQuarantineReceipt, writeStaleMemoryQuarantineReceipt } from "./stale-memory-quarantine.js";
 export type { StaleMemoryClaim, StaleMemoryQuarantineReceipt, StaleMemorySeverity } from "./stale-memory-quarantine.js";
 
+export { createFactoryMemoryFalsificationReceipt, createFalsificationReceipt, writeFalsificationReceipt } from "./falsification-receipt.js";
+export type { FalsificationCase, FalsificationReceipt } from "./falsification-receipt.js";
+
 export { channelPath, emitChannelEvent, readChannelEvents } from "./channel.js";
 export type { ChannelEvent, ChannelEventSource, ChannelEventType, NewChannelEvent } from "./channel.js";
 
diff --git a/src/index.ts b/src/index.ts
index c92ac4c..b60d9d8 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -2319,6 +2319,22 @@ fable
 `);
   });
 
+fable
+  .command("falsification")
+  .description("Write hostile counterexample tests proving dangerous memory claims fail closed")
+  .option("--output <path>", "Receipt output path", path.join(".fable", "learning", "falsification-live.json"))
+  .action(async (opts: { output?: string }) => {
+    const { createFactoryMemoryFalsificationReceipt, writeFalsificationReceipt } = await import("./fable5/falsification-receipt.js");
+    const receipt = createFactoryMemoryFalsificationReceipt();
+    const out = opts.output ?? path.join(".fable", "learning", "falsification-live.json");
+    writeFalsificationReceipt(out, receipt);
+    console.log(JSON.stringify(receipt, null, 2));
+    console.log(`
+  Receipt: ${out}
+`);
+    if (receipt.decision === "failed") process.exit(1);
+  });
+
 fable
   .command("receipt-health")
   .description("Check receipt consumer health over a recent time window")