diff --git a/packages/loopover-engine/src/review/enrichment-analyzer-names.ts b/packages/loopover-engine/src/review/enrichment-analyzer-names.ts
index 7eec217916..1d13489cd4 100644
--- a/packages/loopover-engine/src/review/enrichment-analyzer-names.ts
+++ b/packages/loopover-engine/src/review/enrichment-analyzer-names.ts
@@ -26,6 +26,7 @@ export const REES_ANALYZER_NAMES = [
   "history",
   "docCommentDrift",
   "duplication",
+  "duplicationDelta",
   "churnHotspot",
   "blameLink",
   "approvalIntegrity",
diff --git a/src/review/enrichment-analyzer-names.ts b/src/review/enrichment-analyzer-names.ts
index 7eec217916..1d13489cd4 100644
--- a/src/review/enrichment-analyzer-names.ts
+++ b/src/review/enrichment-analyzer-names.ts
@@ -26,6 +26,7 @@ export const REES_ANALYZER_NAMES = [
   "history",
   "docCommentDrift",
   "duplication",
+  "duplicationDelta",
   "churnHotspot",
   "blameLink",
   "approvalIntegrity",
diff --git a/test/unit/enrichment-analyzers-taxonomy.test.ts b/test/unit/enrichment-analyzers-taxonomy.test.ts
index 2f191415ff..329c98d43b 100644
--- a/test/unit/enrichment-analyzers-taxonomy.test.ts
+++ b/test/unit/enrichment-analyzers-taxonomy.test.ts
@@ -5,6 +5,8 @@ import {
   buildEnrichmentAnalyzersTaxonomyDocument,
   ENRICHMENT_ANALYZERS_URI,
 } from "../../src/review/enrichment-analyzers-taxonomy";
+import { REES_ANALYZER_NAMES } from "../../src/review/enrichment-analyzer-names";
+import { REES_ANALYZER_NAMES as ENGINE_REES_ANALYZER_NAMES } from "../../packages/loopover-engine/src/review/enrichment-analyzer-names";
 
 const metadataPath = join(process.cwd(), "review-enrichment/analyzer-metadata.json");
 
@@ -45,3 +47,34 @@ describe("enrichment analyzers taxonomy document", () => {
     expect(ENRICHMENT_ANALYZERS_URI).toBe("gittensory://enrichment-analyzers");
   });
 });
+
+describe("REES_ANALYZER_NAMES stays in sync with analyzer-metadata.json", () => {
+  const metadataNames = (
+    JSON.parse(readFileSync(metadataPath, "utf8")) as { analyzers: Array<{ name: string }> }
+  ).analyzers.map((a) => a.name);
+
+  it("covers exactly the analyzers the metadata registry defines (no missing, no extra)", () => {
+    // The canonical name list validates every operator `REES_ANALYZERS` env entry and per-repo
+    // `.loopover.yml review.enrichment` toggle, so an analyzer present in the metadata registry but absent
+    // here is silently un-toggleable/un-selectable. Compared as sets against the registry (the source of
+    // truth) rather than a hardcoded count so a newly-added analyzer can't drift the two apart unnoticed.
+    expect(new Set(REES_ANALYZER_NAMES)).toEqual(new Set(metadataNames));
+  });
+
+  it("includes duplicationDelta alongside duplication (regression for the one-entry gap)", () => {
+    expect(REES_ANALYZER_NAMES).toContain("duplication");
+    expect(REES_ANALYZER_NAMES).toContain("duplicationDelta");
+  });
+
+  it("has no duplicate entries", () => {
+    expect(new Set(REES_ANALYZER_NAMES).size).toBe(REES_ANALYZER_NAMES.length);
+  });
+
+  it("stays in lockstep with the loopover-engine twin copy (same names, same order)", () => {
+    // enrichment-analyzer-names.ts is duplicated across the server (`src/`) and the engine package
+    // (`packages/loopover-engine/src/`) as a leaf module the engine-parity contract keeps byte-identical.
+    // Assert the two exported lists by value so a name added to one copy but not the other — e.g. the
+    // duplicationDelta gap this fixes — is caught as a divergence rather than silently drifting.
+    expect([...ENGINE_REES_ANALYZER_NAMES]).toEqual([...REES_ANALYZER_NAMES]);
+  });
+});