diff --git a/scripts/release-publication-receipt.mjs b/scripts/release-publication-receipt.mjs
index 8e66d6325..74c3592e0 100644
--- a/scripts/release-publication-receipt.mjs
+++ b/scripts/release-publication-receipt.mjs
@@ -9,6 +9,7 @@ import {
   writeFileSync,
 } from "node:fs";
 import { basename, dirname, resolve } from "node:path";
+import { hasDuplicateJsonObjectKeys } from "./normalize-commercial-readiness-evidence.mjs";
 
 const EXPECTED_REPOSITORY = "ContextualWisdomLab/noema";
 const MAX_JSON_BYTES = 16 * 1024 * 1024;
@@ -105,6 +106,9 @@ function readJson(path, label) {
     fail(`${label} is not valid UTF-8: ${error instanceof Error ? error.message : String(error)}`);
   }
   try {
+    if (hasDuplicateJsonObjectKeys(text)) {
+      fail(`${label} contains duplicate object keys`);
+    }
     const value = JSON.parse(text);
     if (!value || typeof value !== "object" || Array.isArray(value)) {
       fail(`${label} must contain a JSON object`);
diff --git a/test/release-publication-duplicate-json.test.ts b/test/release-publication-duplicate-json.test.ts
new file mode 100644
index 000000000..93d5a466f
--- /dev/null
+++ b/test/release-publication-duplicate-json.test.ts
@@ -0,0 +1,146 @@
+import { createHash } from "node:crypto";
+import { existsSync, mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { basename, join } from "node:path";
+import { spawnSync } from "node:child_process";
+import { describe, expect, it } from "vitest";
+
+const repository = "ContextualWisdomLab/noema";
+const commitSha = "a".repeat(40);
+const version = "0.1.0";
+const tag = `v${version}`;
+
+function digest(path: string) {
+  return createHash("sha256").update(readFileSync(path)).digest("hex");
+}
+
+function writeJson(path: string, value: unknown) {
+  writeFileSync(path, `${JSON.stringify(value)}\n`, "utf8");
+}
+
+describe("release publication JSON integrity", () => {
+  it("rejects duplicate decoded policy keys instead of accepting last-key-wins evidence", () => {
+    const temp = mkdtempSync(join(tmpdir(), "noema-release-publication-duplicate-json-"));
+    try {
+      const releaseDir = join(temp, "release");
+      const attestationsDir = join(releaseDir, "attestations");
+      mkdirSync(attestationsDir, { recursive: true });
+
+      const sourceName = `noema-${commitSha}.tar.gz`;
+      const sourcePath = join(releaseDir, sourceName);
+      const sbomPath = join(releaseDir, "noema.cdx.json");
+      const evidencePath = join(releaseDir, "release-evidence.json");
+      const checksumsPath = join(releaseDir, "SHA256SUMS");
+      const provenancePath = join(attestationsDir, "provenance.sigstore.json");
+      const cyclonedxPath = join(attestationsDir, "cyclonedx-sbom.sigstore.json");
+
+      writeFileSync(sourcePath, "bounded source archive", "utf8");
+      writeJson(sbomPath, {
+        bomFormat: "CycloneDX",
+        specVersion: "1.5",
+        metadata: { component: { type: "application", name: "noema", version } },
+      });
+      writeJson(provenancePath, { mediaType: "application/vnd.dev.sigstore.bundle.v0.3+json" });
+      writeJson(cyclonedxPath, { mediaType: "application/vnd.dev.sigstore.bundle.v0.3+json" });
+      writeJson(evidencePath, {
+        schemaVersion: 1,
+        source: { repository, commitSha, ref: `refs/tags/${tag}`, version },
+        subject: {
+          name: sourceName,
+          sha256: digest(sourcePath),
+          bytes: readFileSync(sourcePath).length,
+        },
+        sbom: {
+          name: basename(sbomPath),
+          sha256: digest(sbomPath),
+          bytes: readFileSync(sbomPath).length,
+          bomFormat: "CycloneDX",
+          specVersion: "1.5",
+          rootComponent: { type: "application", name: "noema", version },
+        },
+      });
+      writeFileSync(
+        checksumsPath,
+        [
+          `${digest(sourcePath)}  ${sourceName}`,
+          `${digest(sbomPath)}  noema.cdx.json`,
+          `${digest(evidencePath)}  release-evidence.json`,
+        ].join("\n") + "\n",
+        "utf8",
+      );
+
+      const assetPaths = [sourcePath, sbomPath, evidencePath, checksumsPath, provenancePath, cyclonedxPath];
+      const releaseAssets = assetPaths.map((path) => ({
+        name: basename(path),
+        size: readFileSync(path).length,
+        digest: `sha256:${digest(path)}`,
+      }));
+      const expectedNames = releaseAssets.map(({ name }) => name);
+
+      const policyPath = join(temp, "immutable-policy.json");
+      const releaseViewPath = join(temp, "release-view.json");
+      const releaseApiPath = join(temp, "release-api.json");
+      const verificationPath = join(temp, "release-verification.json");
+      const outputPath = join(temp, "release-publication-receipt.json");
+
+      writeFileSync(
+        policyPath,
+        '{"enabled":false,"en\\u0061bled":true,"enforced_by_owner":true}\n',
+        "utf8",
+      );
+      writeJson(releaseViewPath, {
+        isImmutable: true,
+        tagName: tag,
+        targetCommitish: "main",
+        url: `https://github.com/${repository}/releases/tag/${tag}`,
+        assets: releaseAssets.map(({ name, size }) => ({ name, size })),
+      });
+      writeJson(releaseApiPath, {
+        immutable: true,
+        tag_name: tag,
+        target_commitish: "main",
+        html_url: `https://github.com/${repository}/releases/tag/${tag}`,
+        assets: releaseAssets,
+      });
+      writeJson(verificationPath, {
+        releaseVerified: true,
+        resolvedTagCommitSha: commitSha,
+        verifiedAssets: expectedNames,
+        verifiedAt: "2026-08-14T06:00:00.000Z",
+        workflowRunUrl: `https://github.com/${repository}/actions/runs/123`,
+      });
+
+      const result = spawnSync(
+        process.execPath,
+        [
+          "scripts/release-publication-receipt.mjs",
+          "--policy", policyPath,
+          "--release-view", releaseViewPath,
+          "--release-api", releaseApiPath,
+          "--verification", verificationPath,
+          "--release-evidence", evidencePath,
+          "--asset-dir", releaseDir,
+          "--output", outputPath,
+        ],
+        {
+          cwd: process.cwd(),
+          env: {
+            ...process.env,
+            GITHUB_REPOSITORY: repository,
+            NOEMA_RELEASE_TAG: tag,
+            NOEMA_RELEASE_COMMIT_SHA: commitSha,
+            NOEMA_RELEASE_VERSION: version,
+            NOEMA_RELEASE_GENERATED_AT: "2026-08-14T06:00:01.000Z",
+          },
+          encoding: "utf8",
+        },
+      );
+
+      expect(result.status).toBe(1);
+      expect(result.stderr).toContain("duplicate object keys");
+      expect(existsSync(outputPath)).toBe(false);
+    } finally {
+      rmSync(temp, { recursive: true, force: true });
+    }
+  });
+});