diff --git a/scripts/check-engine-parity.ts b/scripts/check-engine-parity.ts
index ab5bc3500f..7e8e7d529d 100644
--- a/scripts/check-engine-parity.ts
+++ b/scripts/check-engine-parity.ts
@@ -147,6 +147,45 @@ export const SECRET_DETECTION_MARKERS = Object.freeze([
   '"generic_secret_assignment"',
 ] as const);
 
+/** `scripts/forbidden-content.ts`'s FORBIDDEN_CONTENT is a THIRD hand-copy (#7433) of the HARD_SECRET_KINDS
+ *  regex bodies in `src/review/secret-patterns.ts` — the four package-manifest checkers (check-mcp/miner/
+ *  engine/ui-kit-package.ts) use it to reject a packed tarball embedding a provider secret. Unlike the REES
+ *  pair it was never drift-checked, so a tightened or added HARD_SECRET_KINDS pattern would silently leave
+ *  packaged MCP/miner/engine/ui-kit scanning with a stale body, with no CI signal (#8674). Registered here so
+ *  a divergence in any of the shared regex bodies fails CI. */
+export const FORBIDDEN_CONTENT_TWIN_PAIR: NamedTwinPair = Object.freeze({
+  area: "forbidden-content-secret-patterns",
+  hostRelative: "src/review/secret-patterns.ts",
+  engineRelative: "scripts/forbidden-content.ts",
+  hostFileName: "secret-patterns.ts",
+  engineFileName: "forbidden-content.ts",
+});
+
+// The distinctive core of each HARD_SECRET_KINDS regex body that forbidden-content.ts hand-copied EXACTLY
+// (#7433/#8396). Anchored on the backslash-free inner body, NOT the `\b`/`\.` escapes (which necessarily differ
+// between secret-patterns.ts's regex literals — single `\` — and forbidden-content.ts's string bodies — double
+// `\\`), so a merely-reformatted boundary never false-fails while a change to the actual character class /
+// length / watermark of any shared pattern does. `github_token`/`github_pat`/`private_key_block` are
+// DELIBERATELY EXCLUDED: forbidden-content.ts keeps its own looser pre-#7433 bodies for those three (e.g.
+// `gh[pousr]_[A-Za-z0-9_]+` vs secret-patterns.ts's `gh[pousr]_[A-Za-z0-9]{20,}`), a pre-existing intentional
+// divergence — including them would false-fail this check on the very PR that introduces it, exactly as
+// SECRET_DETECTION_MARKERS excludes its own two naming-divergent kinds.
+export const FORBIDDEN_CONTENT_MARKERS = Object.freeze([
+  "AKIA[0-9A-Z]{16}", // aws_access_key
+  "xox[baprs]-[A-Za-z0-9-]{10,}", // slack_token
+  "AIza[0-9A-Za-z_-]{35}", // google_api_key
+  "glpat-[0-9A-Za-z_-]{20}(?![0-9A-Za-z_-])", // gitlab_token
+  "npm_[A-Za-z0-9]{36}", // npm_token
+  "(?:sk|rk)_live_[0-9A-Za-z]{24,}", // stripe_secret_key
+  "[A-Za-z0-9_-]{43}(?![A-Za-z0-9_-])", // sendgrid_key (the distinctive 43-char secret half)
+  "hf_[A-Za-z0-9]{34}", // huggingface_token
+  "(?:pa|al)-[A-Za-z0-9]{20,}(?![A-Za-z0-9_-])", // voyage_api_key
+  "fc-[A-Za-z0-9]{16,}(?![A-Za-z0-9_-])", // firecrawl_api_key
+  "sk-(?:proj-|svcacct-|admin-)?[A-Za-z0-9_-]{20,}T3BlbkFJ[A-Za-z0-9_-]{20,}", // openai_api_key
+  "sk-ant-api03-[A-Za-z0-9_-]{93}AA", // anthropic_api_key
+  "eyJ[A-Za-z0-9_-]{10,}", // jwt (#8396)
+] as const);
+
 /** Every explicitly named twin pair, checked for core-marker presence in `runEngineParityChecks` — the
  *  same escape hatch #4518 built for `GATE_DECISION_TWIN_PAIR`, generalized (#4605) so a function-level or
  *  nested-directory duplicate can be added here without inventing a new mechanism. `GATE_DECISION_TWIN_PAIR`
@@ -163,6 +202,7 @@ export const NAMED_TWIN_PAIRS: ReadonlyArray<{ pair: NamedTwinPair; markers: rea
   { pair: DIFF_FILE_PRIORITY_GROUNDING_TWIN_PAIR, markers: DIFF_FILE_PRIORITY_MARKERS },
   { pair: SHARES_MEANINGFUL_FILE_TWIN_PAIR, markers: SHARES_MEANINGFUL_FILE_MARKERS },
   { pair: SECRET_DETECTION_TWIN_PAIR, markers: SECRET_DETECTION_MARKERS },
+  { pair: FORBIDDEN_CONTENT_TWIN_PAIR, markers: FORBIDDEN_CONTENT_MARKERS },
 ]);
 const ENGINE_SRC_ROOT = "packages/loopover-engine/src";
 const HOST_SRC_ROOT = "src";
diff --git a/test/unit/check-engine-parity-script.test.ts b/test/unit/check-engine-parity-script.test.ts
index bdd206fa5e..f759edfe2c 100644
--- a/test/unit/check-engine-parity-script.test.ts
+++ b/test/unit/check-engine-parity-script.test.ts
@@ -21,6 +21,8 @@ import {
   discoverGateDecisionTwinPair,
   enginePackageVersionIncreased,
   extractForbiddenTermsRegex,
+  FORBIDDEN_CONTENT_MARKERS,
+  FORBIDDEN_CONTENT_TWIN_PAIR,
   GATE_DECISION_TWIN_PAIR,
   type EngineParityPair,
   isEngineStubPair,
@@ -456,7 +458,7 @@ const CHECK_RUN_FORBIDDEN_TERMS =
   });
 
   describe("named twin-pair coverage (#4605)", () => {
-    it("registers the gate-decision, content-lane, diff-file-priority twins, shares-meaningful-file, and secret-detection pairs", () => {
+    it("registers the gate-decision, content-lane, diff-file-priority, diff-file-priority-grounding, shares-meaningful-file, secret-detection, and forbidden-content pairs", () => {
       const areas = NAMED_TWIN_PAIRS.map(({ pair }) => pair.area);
       expect(areas).toEqual([
         "gate-decision",
@@ -465,6 +467,7 @@ const CHECK_RUN_FORBIDDEN_TERMS =
         "diff-file-priority-grounding",
         "shares-meaningful-file",
         "secret-detection",
+        "forbidden-content-secret-patterns",
       ]);
     });
 
@@ -635,6 +638,45 @@ const CHECK_RUN_FORBIDDEN_TERMS =
     });
   });
 
+  describe("forbidden-content twin coverage (#8674)", () => {
+    it("registers scripts/forbidden-content.ts against src/review/secret-patterns.ts", () => {
+      expect(FORBIDDEN_CONTENT_TWIN_PAIR.hostRelative).toBe("src/review/secret-patterns.ts");
+      expect(FORBIDDEN_CONTENT_TWIN_PAIR.engineRelative).toBe("scripts/forbidden-content.ts");
+    });
+
+    it("excludes the three kinds whose forbidden-content bodies deliberately diverge (github_token/github_pat/private_key_block)", () => {
+      // Those three keep looser pre-#7433 bodies in forbidden-content.ts (e.g. `gh[pousr]_[A-Za-z0-9_]+`);
+      // asserting their absence documents the deliberate omission and guards against someone "completing the
+      // set" and reintroducing a false-fail, exactly as the secret-detection pair does for its own divergences.
+      const joined = FORBIDDEN_CONTENT_MARKERS.join("\n");
+      expect(joined).not.toContain("gh[pousr]_");
+      expect(joined).not.toContain("github_pat_");
+      expect(joined).not.toContain("PRIVATE KEY");
+    });
+
+    it("fails presence when a shared HARD_SECRET_KINDS regex body drifts between the two copies", () => {
+      // Reproduces the drift class this pair exists to catch (#8674): a HARD_SECRET_KINDS body is tightened in
+      // secret-patterns.ts while forbidden-content.ts's hand-copy is left stale, silently packaging tarballs
+      // with an outdated scanner. Both bodies start from the FULL marker set so only the dropped line fails.
+      const droppedMarker = "sk-ant-api03-[A-Za-z0-9_-]{93}AA";
+      const hostBody = FORBIDDEN_CONTENT_MARKERS.join("\n");
+      const driftedTwinBody = FORBIDDEN_CONTENT_MARKERS.filter((marker) => marker !== droppedMarker).join("\n");
+      const result = checkGateDecisionTwinPresence({
+        root: "/fake",
+        readFile: (_root, relativePath) => {
+          if (relativePath === FORBIDDEN_CONTENT_TWIN_PAIR.hostRelative) return hostBody;
+          if (relativePath === FORBIDDEN_CONTENT_TWIN_PAIR.engineRelative) return driftedTwinBody;
+          throw new Error(`unexpected read: ${relativePath}`);
+        },
+        pair: FORBIDDEN_CONTENT_TWIN_PAIR,
+        markers: FORBIDDEN_CONTENT_MARKERS,
+      });
+      expect(result.failures).toHaveLength(1);
+      expect(result.failures[0]).toContain(FORBIDDEN_CONTENT_TWIN_PAIR.engineRelative);
+      expect(result.failures[0]).toContain(JSON.stringify(droppedMarker));
+    });
+  });
+
   describe("engine version skew", () => {
     it("classifies equal, behind, and ahead boundary cases", () => {
       expect(compareSemver("0.2.0", "0.2.0")).toBe(0);