diff --git a/scripts/check-plugin-sdk-exports.mjs b/scripts/check-plugin-sdk-exports.mjs
index 11af131c1fb2..31cda1dd1c17 100755
--- a/scripts/check-plugin-sdk-exports.mjs
+++ b/scripts/check-plugin-sdk-exports.mjs
@@ -14,6 +14,7 @@ import { fileURLToPath, pathToFileURL } from "node:url";
 import {
   MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
   MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
+  PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES,
   evaluatePluginSdkDeclarationBudget,
   isPrivateQaPluginSdkBuild,
 } from "./lib/plugin-sdk-declaration-budget.mjs";
@@ -186,15 +187,18 @@ if (declarationBudget.shouldFail) {
   console.error(
     `${budgetLabel} DTS TOO LARGE: ${declarationBytes} bytes exceeds ${declarationBudget.budgetBytes} bytes.`,
   );
+  console.error(
+    `Budget: ${declarationBudget.ratchetBytes}-byte ratchet + ${declarationBudget.varianceBytes}-byte Rolldown output variance.`,
+  );
   console.error("Keep plugin SDK declarations in the canonical unified tsdown graph.");
   missing += 1;
 } else if (declarationBudget.budgetKind === "private-qa-public-entry") {
   console.log(
-    `Private QA build public-entry declaration graph: ${declarationBytes}/${MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES} bytes; publication budget ${MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES} bytes is not applied.`,
+    `Private QA build public-entry declaration graph: ${declarationBytes}/${declarationBudget.budgetBytes} bytes (${MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES}-byte ratchet + ${PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES}-byte output variance); publication ratchet ${MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES} bytes is not applied.`,
   );
 } else {
   console.log(
-    `Public plugin SDK declaration graph: ${declarationBytes}/${MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES} bytes.`,
+    `Public plugin SDK declaration graph: ${declarationBytes}/${declarationBudget.budgetBytes} bytes (${MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES}-byte ratchet + ${PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES}-byte output variance).`,
   );
 }
 
diff --git a/scripts/lib/plugin-sdk-declaration-budget.d.mts b/scripts/lib/plugin-sdk-declaration-budget.d.mts
index bde50e334fdc..c3129f8ee11f 100644
--- a/scripts/lib/plugin-sdk-declaration-budget.d.mts
+++ b/scripts/lib/plugin-sdk-declaration-budget.d.mts
@@ -8,7 +8,10 @@ export function evaluatePluginSdkDeclarationBudget({
 }): {
   budgetBytes: number;
   budgetKind: string;
+  ratchetBytes: number;
   shouldFail: boolean;
+  varianceBytes: number;
 };
 export const MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES: 5200000;
 export const MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES: 5225000;
+export const PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES: 65536;
diff --git a/scripts/lib/plugin-sdk-declaration-budget.mjs b/scripts/lib/plugin-sdk-declaration-budget.mjs
index 259291a0f150..3fa0be1bc583 100644
--- a/scripts/lib/plugin-sdk-declaration-budget.mjs
+++ b/scripts/lib/plugin-sdk-declaration-budget.mjs
@@ -4,18 +4,24 @@ export const MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES = 5_200_000;
 // Private-only entrypoints reshape chunks reachable from public roots but are never published.
 // Bound that topology overhead without counting local-only declarations as package surface.
 export const MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES = 5_225_000;
+// Rolldown can repartition equivalent declaration chunks between clean builds; measured spread is
+// about 29 KiB across hosts. Keep one 64 KiB scheduling window above the intentional size ratchet.
+export const PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES = 64 * 1024;
 
 export function isPrivateQaPluginSdkBuild(env) {
   return env.OPENCLAW_BUILD_PRIVATE_QA === "1";
 }
 
 export function evaluatePluginSdkDeclarationBudget({ declarationBytes, buildPrivateQa }) {
-  const budgetBytes = buildPrivateQa
+  const ratchetBytes = buildPrivateQa
     ? MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES
     : MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES;
+  const budgetBytes = ratchetBytes + PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES;
   return {
     budgetBytes,
     budgetKind: buildPrivateQa ? "private-qa-public-entry" : "public",
+    ratchetBytes,
     shouldFail: declarationBytes > budgetBytes,
+    varianceBytes: PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES,
   };
 }
diff --git a/test/scripts/plugin-sdk-declaration-budget.test.ts b/test/scripts/plugin-sdk-declaration-budget.test.ts
index 0d1dddeab2d9..838ffdf87952 100644
--- a/test/scripts/plugin-sdk-declaration-budget.test.ts
+++ b/test/scripts/plugin-sdk-declaration-budget.test.ts
@@ -2,6 +2,7 @@ import { describe, expect, it } from "vitest";
 import {
   MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
   MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
+  PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES,
   evaluatePluginSdkDeclarationBudget,
   isPrivateQaPluginSdkBuild,
 } from "../../scripts/lib/plugin-sdk-declaration-budget.mjs";
@@ -14,48 +15,61 @@ describe("plugin SDK declaration budget", () => {
   });
 
   it("enforces the publication budget at its exact boundary", () => {
+    const budgetBytes =
+      MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES + PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES;
     expect(
       evaluatePluginSdkDeclarationBudget({
         buildPrivateQa: false,
-        declarationBytes: MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
+        declarationBytes: budgetBytes,
       }),
     ).toEqual({
-      budgetBytes: MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
+      budgetBytes,
       budgetKind: "public",
+      ratchetBytes: MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
       shouldFail: false,
+      varianceBytes: PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES,
     });
     expect(
       evaluatePluginSdkDeclarationBudget({
         buildPrivateQa: false,
-        declarationBytes: MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES + 1,
+        declarationBytes: budgetBytes + 1,
       }),
     ).toEqual({
-      budgetBytes: MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
+      budgetBytes,
       budgetKind: "public",
+      ratchetBytes: MAX_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
       shouldFail: true,
+      varianceBytes: PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES,
     });
   });
 
   it("tracks private-build public-entry chunk growth under a separate budget", () => {
+    const budgetBytes =
+      MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES +
+      PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES;
     expect(
       evaluatePluginSdkDeclarationBudget({
         buildPrivateQa: true,
-        declarationBytes: MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
+        declarationBytes: budgetBytes,
       }),
     ).toEqual({
-      budgetBytes: MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
+      budgetBytes,
       budgetKind: "private-qa-public-entry",
+      ratchetBytes: MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
       shouldFail: false,
+      varianceBytes: PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES,
     });
     expect(
       evaluatePluginSdkDeclarationBudget({
         buildPrivateQa: true,
-        declarationBytes: MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES + 1,
+        declarationBytes: budgetBytes + 1,
       }),
     ).toEqual({
-      budgetBytes: MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
+      budgetBytes,
       budgetKind: "private-qa-public-entry",
+      ratchetBytes: MAX_PRIVATE_QA_PUBLIC_PLUGIN_SDK_DECLARATION_BYTES,
       shouldFail: true,
+      varianceBytes: PLUGIN_SDK_DECLARATION_OUTPUT_VARIANCE_BYTES,
     });
   });
 });