diff --git a/.github/workflows/gate.yml b/.github/workflows/gate.yml
index 102a56ebf..7ea8a24ad 100644
--- a/.github/workflows/gate.yml
+++ b/.github/workflows/gate.yml
@@ -736,6 +736,34 @@ jobs:
       - name: Run check-archive-header-section33
         run: bun tools/hygiene/check-archive-header-section33.ts
 
+  lint-section-33-migration-xrefs:
+    # Fail if any live-nav surface (.claude/, memory/*.md top-level,
+    # docs/backlog/, repo-root *.md) still references docs/research/<basename>
+    # where <basename> has been migrated to memory/persona/<persona>/conversations/.
+    #
+    # Sibling of lint-archive-header-section33 (B-0036): same shape, different
+    # failure-class. The §33 migration pattern moves files but does not
+    # auto-update backlinks; without this lint, dead xrefs accumulate silently
+    # (empirical baseline 2026-05-15 before cleanup: 10 dead xrefs across 6 files;
+    # full discovery: PR #3513 → Codex P2 → narrow fix PR #3529 → scanner
+    # PR #3548 → baseline cleanup PR #3552).
+    #
+    # B-0533 Slice B.3 + B.4 — wire the scanner to gate.yml in --enforce mode
+    # after PR #3552 backfilled all pre-existing violations to 0.
+    name: lint (§33 migration xrefs)
+    timeout-minutes: 2
+    runs-on: ubuntu-24.04
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Install toolchain via three-way-parity script (GOVERNANCE §24)
+        run: ./tools/setup/install.sh
+
+      - name: Run audit-section-33-migration-xrefs (--enforce)
+        run: bun tools/hygiene/audit-section-33-migration-xrefs.ts --enforce
+
   lint-no-empty-dirs:
     # Fail if a committed directory has no files — almost always a
     # forgotten artefact (an agent-created skill folder without a
diff --git a/tools/hygiene/audit-section-33-migration-xrefs.ts b/tools/hygiene/audit-section-33-migration-xrefs.ts
index b9c58205f..fa7f13bfe 100644
--- a/tools/hygiene/audit-section-33-migration-xrefs.ts
+++ b/tools/hygiene/audit-section-33-migration-xrefs.ts
@@ -32,10 +32,12 @@
 //
 //   bun tools/hygiene/audit-section-33-migration-xrefs.ts                # detect-only
 //   bun tools/hygiene/audit-section-33-migration-xrefs.ts --report PATH  # write markdown report
+//   bun tools/hygiene/audit-section-33-migration-xrefs.ts --enforce      # exit non-zero on findings
 //
 // Exit codes:
 //
-//   0   always (detect-only; humans triage candidates before fixing)
+//   0   no findings, OR detect-only mode (default)
+//   1   findings present AND --enforce flag set (CI gate)
 //   64  argument error
 //
 // Composes with: audit-rule-cross-refs.ts (template), B-0532 (sibling lint pattern),
@@ -46,12 +48,13 @@ import { join, relative } from "node:path";
 
 const PERSONA_BASE = "memory/persona";
 const LIVE_NAV_SURFACES = [".claude/rules", ".claude/agents", ".claude/commands", ".claude/skills", "memory", "docs/backlog"];
-const ROOT_MD = ["CLAUDE.md", "AGENTS.md", "README.md", "GOVERNANCE.md"];
+const ROOT_MD = readdirSync(".").filter(f => f.endsWith(".md"));
 
-type AuditExitCode = 0 | 64;
+type AuditExitCode = 0 | 1 | 64;
 
 interface Args {
     readonly report: string | null;
+    readonly enforce: boolean;
 }
 
 interface DeadXref {
@@ -71,6 +74,7 @@ interface AuditResult {
 
 function parseArgs(argv: string[]): { kind: "args"; args: Args } | { kind: "error"; message: string } {
     let report: string | null = null;
+    let enforce = false;
     let i = 0;
     while (i < argv.length) {
         const a = argv[i]!;
@@ -79,11 +83,14 @@ function parseArgs(argv: string[]): { kind: "args"; args: Args } | { kind: "erro
             if (!next) return { kind: "error", message: "--report requires a path" };
             report = next;
             i += 2;
+        } else if (a === "--enforce") {
+            enforce = true;
+            i += 1;
         } else {
             return { kind: "error", message: `Unknown argument: ${a}` };
         }
     }
-    return { kind: "args", args: { report } };
+    return { kind: "args", args: { report, enforce } };
 }
 
 // Build basename to persona index by walking memory/persona/*/conversations/
@@ -274,6 +281,10 @@ function main(argv: string[]): AuditExitCode {
         console.log(report);
     }
 
+    if (parsed.args.enforce && result.deadXrefs.length > 0) {
+        console.error(`error: ${result.deadXrefs.length} dead xref(s) found; --enforce flag set`);
+        return 1;
+    }
     return 0;
 }