diff --git a/tools/sql-migration-gate/index.test.ts b/tools/sql-migration-gate/index.test.ts
index dad5e9dd1..956afe8f2 100644
--- a/tools/sql-migration-gate/index.test.ts
+++ b/tools/sql-migration-gate/index.test.ts
@@ -580,6 +580,26 @@ console.log(JSON.stringify(await checkMigrationImmutability(${JSON.stringify(roo
 			rmSync(root, { recursive: true, force: true });
 		}
 	});
+
+	test("the gate entrypoint fails on an edited base migration", async () => {
+		const path = "go/internal/store/migrations/0001_init.sql";
+		await withRepo({ [path]: "SELECT 1;\n" }, async (root) => {
+			writeFileSync(join(root, path), "SELECT 2;\n");
+			const child = Bun.spawn(
+				[process.execPath, join(import.meta.dir, "index.ts")],
+				{
+					cwd: root,
+					env: { ...process.env, GATE_ROOT: root, GATE_BASE_REF: "base" },
+					stdout: "pipe",
+					stderr: "pipe",
+				},
+			);
+			const stderr = await new Response(child.stderr).text();
+			expect(await child.exited, stderr).toBe(1);
+			expect(stderr).toContain(path);
+			expect(stderr).toContain("FAIL — findings from migration-immutability");
+		});
+	});
 });
 
 // ---------------------------------------------------------------------------
diff --git a/tools/sql-migration-gate/index.ts b/tools/sql-migration-gate/index.ts
index 0da85d614..afbcade9c 100644
--- a/tools/sql-migration-gate/index.ts
+++ b/tools/sql-migration-gate/index.ts
@@ -396,14 +396,7 @@ if (import.meta.main) {
 			runLinter: makeSpawnLinter(root),
 			log: (msg) => console.log(msg),
 			err: (msg) => console.error(msg),
-			// Suspended while open migration PRs fold into 0001_init.sql; restore
-			// `checkMigrationImmutability(root)` once the dev DB is wiped.
-			runMigrationCheck: async () => ({
-				name: "migration-immutability",
-				code: 0,
-				output:
-					"sql-migration-gate: migration-immutability suspended for the 0001 collapse",
-			}),
+			runMigrationCheck: () => checkMigrationImmutability(root),
 		}),
 	);
 }