diff --git a/docs/operations/adapter-remediation-ledger.md b/docs/operations/adapter-remediation-ledger.md
index d009458..8cc1bf2 100644
--- a/docs/operations/adapter-remediation-ledger.md
+++ b/docs/operations/adapter-remediation-ledger.md
@@ -90,9 +90,9 @@ Rollout state starts at `NOT_STARTED`; documented-unimplemented items start at
 | --- | --- | --- | --- | --- | --- | --- |
 | STO-01 | OPFS not composed in template; **Critical** for any product writer | `corepack pnpm exec vitest run tests/unit/opfs-byte-store.test.ts tests/unit/opfs-worker-runtime.test.ts tests/unit/indexeddb-opfs-journal.test.ts` | `fix: preserve OPFS recovery authority during cleanup` | `FIXED_NOT_RELEASED` | OPFS reconcile backlog or journal growth | Red 4 new saga cases → green 25/25 across the three OPFS suites; `check:types` PASS (incl. web-worker); `check:browser-file-storage-boundaries` PASS; `lint` PASS; `test:unit` 1511 passed with only the pre-existing environmental `ci-artifact-contract` failures |
 | STO-02 | Browser file runtime not composed | `corepack pnpm exec vitest run tests/unit/browser-file-download.test.ts` | `fix: execute canonical browser download targets` | `FIXED_NOT_RELEASED` | download navigation blocked by canonical target | Red 2 failed (raw relative href handed to host) → green 17/17 |
-| STO-03 | Public cache not composed | `corepack pnpm exec vitest run tests/unit/public-response-cache.test.ts` | — | `NOT_STARTED` | composition rejection of an existing policy | — |
-| STO-04 | Public cache not composed | `corepack pnpm exec vitest run tests/unit/public-response-cache.test.ts` | — | `NOT_STARTED` | restage loop or bandwidth spike | — |
-| STO-05 | Public cache not composed | `corepack pnpm exec vitest run tests/unit/public-response-cache.test.ts` | — | `NOT_STARTED` | activation permitted without required capability | — |
+| STO-03 | Public cache not composed | `corepack pnpm exec vitest run tests/unit/public-response-cache.test.ts` | `fix: make public cache staging repairable` | `FIXED_NOT_RELEASED` | composition rejection of an existing policy | Red 4 cases across STO-03..05 → green 21/21; `check:types` PASS; `check:browser-file-storage-boundaries` PASS; `lint` PASS |
+| STO-04 | Public cache not composed | `corepack pnpm exec vitest run tests/unit/public-response-cache.test.ts` | `fix: make public cache staging repairable` | `FIXED_NOT_RELEASED` | restage loop or bandwidth spike | — |
+| STO-05 | Public cache not composed | `corepack pnpm exec vitest run tests/unit/public-response-cache.test.ts` | `fix: make public cache staging repairable` | `FIXED_NOT_RELEASED` | activation permitted without required capability | — |
 | STO-06 | IndexedDB maintenance | `corepack pnpm exec vitest run tests/unit/indexeddb-maintenance.test.ts` | — | `NOT_STARTED` | migration checkpoint stall | — |
 | STO-07 | OPFS worker protocol | `corepack pnpm exec vitest run tests/unit/opfs-worker-runtime.test.ts` | — | `NOT_STARTED` | page/worker `INCOMPATIBLE` spike | — |
 | STO-08 | Hypothesis; browser characterization required | `corepack pnpm exec playwright test --config playwright.capabilities.config.ts tests/browser-capabilities/browser-files.spec.ts` | none (source unchanged) | `UNVERIFIED` | n/a until characterized | chromium 2/2 PASS; webkit could not launch (`libevent-2.1-7t64`, `libavif16` missing — environmental). The existing spec does not exercise `Window.showOpenFilePicker`/`showSaveFilePicker`, which need a user gesture and a native dialog, so the receiver-binding hypothesis is **neither reproduced nor refuted**. No `SystemPickerHost` was introduced: the plan forbids implementing an uncharacterized hypothesis as a defect. |
diff --git a/docs/operations/client-cache-and-storage-recovery.md b/docs/operations/client-cache-and-storage-recovery.md
index 7771936..cd43294 100644
--- a/docs/operations/client-cache-and-storage-recovery.md
+++ b/docs/operations/client-cache-and-storage-recovery.md
@@ -12,6 +12,26 @@ session/account Query lifecycle, strict query policy와 Web Storage v2 lifecycle
 현재 `DESIGNED_NOT_IMPLEMENTED`다. 아래 목표 절차를 현재 runtime의 보장으로
 해석하지 않는다.
 
+
+## Public cache staging repair와 offline activation (STO-03 ~ STO-05)
+
+- release marker는 "staging이 끝났다"는 **주장**이고 모든 entry의 존재·digest
+  증거가 아니다. 같은 manifest로 `stageRelease`를 다시 호출하면 runtime이
+  candidate를 재검증하고, browser eviction이나 부분 손상이 발견되면 그 owned
+  candidate만 삭제한 뒤 network에서 다시 stage한다. marker만 보고 성공을
+  반환하지 않는다.
+- 검증 중 abort나 읽기 불가(UNKNOWN)는 stage 성공이 아니며 active pointer를
+  건드리지 않는다. candidate를 임의로 삭제하지도 않는다.
+- `activateRelease`와 `cleanupOwned`는 network I/O가 없다. fetcher 없이도
+  동작하므로 offline rollback과 quota recovery cleanup이 `UNSUPPORTED`로 막히지
+  않는다. 두 operation은 Cache Storage와 mutation lock만 요구하고 실패 시
+  recovery는 `RETRY`다. `stageRelease`만 fetcher를 요구하며 recovery는
+  `ONLINE_ONLY`다.
+- variant를 사용하는 policy(`allowedVaryHeaderNames` 비어 있지 않음)는 반드시
+  `allowedResponseHeaderNames`에 `vary`를 포함해야 한다. 아니면 composition이
+  `TypeError`로 즉시 실패한다. 저장된 variant가 같은 key로 충돌하는 상태를 만들지
+  않기 위한 cross-field invariant다.
+
 ## 1. 변경할 수 없는 복구 원칙
 
 - 서버가 server state와 authorization의 source of truth다.
diff --git a/src/adapters/cache-storage/public-cache-policy.ts b/src/adapters/cache-storage/public-cache-policy.ts
index f818ba5..0c069e6 100644
--- a/src/adapters/cache-storage/public-cache-policy.ts
+++ b/src/adapters/cache-storage/public-cache-policy.ts
@@ -132,6 +132,11 @@ export function assertPublicCachePolicy(
     policy.allowedVaryHeaderNames.some(
       (name) => !policy.allowedRequestHeaderNames.includes(name),
     ) ||
+    // STO-03. Enabling variants while stripping `vary` from stored responses
+    // makes every variant collide on the same cache key, so the combination is
+    // rejected at composition instead of producing an unusable candidate.
+    (policy.allowedVaryHeaderNames.length > 0 &&
+      !policy.allowedResponseHeaderNames.includes("vary")) ||
     policy.forbiddenQueryParameterNames.some((name) => name.length === 0) ||
     policy.allowedQueryParameterNames.some((name) =>
       policy.forbiddenQueryParameterNames.includes(name),
diff --git a/src/adapters/cache-storage/public-response-cache-adapter.ts b/src/adapters/cache-storage/public-response-cache-adapter.ts
index e3c05d6..c548575 100644
--- a/src/adapters/cache-storage/public-response-cache-adapter.ts
+++ b/src/adapters/cache-storage/public-response-cache-adapter.ts
@@ -241,7 +241,7 @@ export function createPublicResponseCacheAdapter(
       const aborted = abortedResult(signal, "CACHE_LOOKUP");
       if (aborted) return aborted;
       if (!dependencies.cacheStorage) {
-        return unsupported("CACHE_LOOKUP");
+        return unsupported("CACHE_LOOKUP", "RETRY");
       }
       let assetRequest: NormalizedAsset;
       try {
@@ -389,10 +389,7 @@ export function createPublicResponseCacheAdapter(
       const signal = options.signal;
       const aborted = abortedResult(signal, "CACHE_STAGE");
       if (aborted) return aborted;
-      const availability = mutationAvailability(
-        dependencies,
-        "CACHE_STAGE",
-      );
+      const availability = stageAvailability(dependencies);
       if (availability) return availability;
 
       let normalized: NormalizedReleaseManifest;
@@ -438,8 +435,28 @@ export function createPublicResponseCacheAdapter(
                   normalized.manifestDigestHex &&
                 marker.value.entryCount === normalized.assets.length
               ) {
-                return browserDataSuccess(summaryFromMarker(marker.value));
+                // STO-04. The marker is a claim that staging completed, not
+                // evidence that every entry still exists and matches. Browser
+                // eviction, manual deletion and partial corruption all leave the
+                // marker intact, so the candidate is re-verified before reuse.
+                const verified = await verifyReleaseCandidate(
+                  existing,
+                  marker.value.assets,
+                  policy,
+                  dependencies.crypto,
+                  signal,
+                );
+                if (verified.kind === "VERIFIED") {
+                  return browserDataSuccess(summaryFromMarker(marker.value));
+                }
+                if (verified.kind === "UNKNOWN") {
+                  // Abort or an unreadable candidate is never stage success and
+                  // never silently deletes an owned candidate.
+                  return verified.failure;
+                }
               }
+              // Only this owned candidate is removed; the network restage below
+              // repairs it.
               await dependencies.cacheStorage!.delete(cacheName);
             }
 
@@ -535,7 +552,7 @@ export function createPublicResponseCacheAdapter(
       const signal = options.signal;
       const aborted = abortedResult(signal, "CACHE_ACTIVATE");
       if (aborted) return aborted;
-      const availability = mutationAvailability(
+      const availability = localMutationAvailability(
         dependencies,
         "CACHE_ACTIVATE",
       );
@@ -589,31 +606,25 @@ export function createPublicResponseCacheAdapter(
               );
             }
 
-            for (const asset of marker.assets) {
-              if (signal?.aborted) {
-                return browserDataFailure("ABORTED", "CACHE_ACTIVATE");
-              }
-              const cached = await cache.match(createNativeRequest(asset));
-              if (!cached) {
-                return browserDataFailure(
-                  "INTEGRITY_FAILED",
-                  "CACHE_ACTIVATE",
-                  { recovery: "REHYDRATE" },
-                );
-              }
-              const verified = await readAndValidateResponse(
-                cached,
-                asset,
-                policy,
-                dependencies.crypto,
-                signal,
+            const candidate = await verifyReleaseCandidate(
+              cache,
+              marker.assets,
+              policy,
+              dependencies.crypto,
+              signal,
+            );
+            if (candidate.kind === "UNKNOWN") {
+              return rebaseFailure(
+                candidate.failure.error,
+                "CACHE_ACTIVATE",
+              );
+            }
+            if (candidate.kind === "REPAIRABLE") {
+              return browserDataFailure(
+                "INTEGRITY_FAILED",
+                "CACHE_ACTIVATE",
+                { recovery: "REHYDRATE" },
               );
-              if (!verified.ok) {
-                return rebaseFailure(
-                  verified.error,
-                  "CACHE_ACTIVATE",
-                );
-              }
             }
 
             const previousPointer = await readActivePointer(
@@ -692,7 +703,7 @@ export function createPublicResponseCacheAdapter(
       const signal = request.signal;
       const aborted = abortedResult(signal, "CACHE_DELETE");
       if (aborted) return aborted;
-      const availability = mutationAvailability(
+      const availability = localMutationAvailability(
         dependencies,
         "CACHE_DELETE",
       );
@@ -771,7 +782,7 @@ export function createPublicResponseCacheAdapter(
 
     async inspect() {
       if (!dependencies.cacheStorage) {
-        return unsupported("CACHE_LOOKUP");
+        return unsupported("CACHE_LOOKUP", "RETRY");
       }
       try {
         const names = await dependencies.cacheStorage.keys();
@@ -1640,24 +1651,104 @@ function summaryFromMarker(
   });
 }
 
-function mutationAvailability(
+type ReleaseCandidateVerdict =
+  | Readonly<{ kind: "VERIFIED" }>
+  /** An exact, owned entry is missing or no longer matches the manifest. */
+  | Readonly<{ kind: "REPAIRABLE" }>
+  /** Abort or an unreadable candidate: never success, never a silent delete. */
+  | Readonly<{ kind: "UNKNOWN"; failure: BrowserFailureResult }>;
+
+/**
+ * STO-04. The single verification authority shared by the stage fast path and
+ * activation, so "the marker says it is staged" can never stand in for "every
+ * entry is present and matches".
+ */
+async function verifyReleaseCandidate(
+  cache: Readonly<{ match(request: Request): Promise<Response | undefined> }>,
+  assets: readonly NormalizedAsset[],
+  policy: PublicCacheRuntimePolicy,
+  crypto: Readonly<{
+    digestSha256(bytes: Uint8Array): Promise<ArrayBuffer>;
+  }>,
+  signal: AbortSignal | undefined,
+): Promise<ReleaseCandidateVerdict> {
+  for (const asset of assets) {
+    if (signal?.aborted) {
+      return Object.freeze({
+        kind: "UNKNOWN" as const,
+        failure: asFailure(
+          browserDataFailure("ABORTED", "CACHE_ACTIVATE"),
+        ),
+      });
+    }
+    let cached: Response | undefined;
+    try {
+      cached = await cache.match(createNativeRequest(asset));
+    } catch {
+      return Object.freeze({
+        kind: "UNKNOWN" as const,
+        failure: asFailure(
+          browserDataFailure("UNAVAILABLE", "CACHE_ACTIVATE", {
+            retryable: true,
+            recovery: "RETRY",
+          }),
+        ),
+      });
+    }
+    if (!cached) return Object.freeze({ kind: "REPAIRABLE" as const });
+    const verified = await readAndValidateResponse(
+      cached,
+      asset,
+      policy,
+      crypto,
+      signal,
+    );
+    if (!verified.ok) {
+      return verified.error.code === "ABORTED"
+        ? Object.freeze({
+            kind: "UNKNOWN" as const,
+            failure: asFailure(verified),
+          })
+        : Object.freeze({ kind: "REPAIRABLE" as const });
+    }
+  }
+  return Object.freeze({ kind: "VERIFIED" as const });
+}
+
+/**
+ * STO-05. Staging is the only operation that reaches the network, so it is the
+ * only one that requires a fetcher.
+ */
+function stageAvailability(
   dependencies: PublicResponseCacheDependencySnapshot,
-  operation: BrowserDataOperation,
 ): BrowserFailureResult | null {
   return dependencies.cacheStorage &&
     dependencies.fetcher &&
     dependencies.mutationLock
     ? null
-    : unsupported(operation);
+    : unsupported("CACHE_STAGE", "ONLINE_ONLY");
+}
+
+/**
+ * Activation, rollback and cleanup are local Cache Storage mutations. Requiring
+ * a fetcher would block an offline rollback or a quota-recovery cleanup that
+ * needs no network at all.
+ */
+function localMutationAvailability(
+  dependencies: PublicResponseCacheDependencySnapshot,
+  operation: "CACHE_ACTIVATE" | "CACHE_DELETE",
+): BrowserFailureResult | null {
+  return dependencies.cacheStorage && dependencies.mutationLock
+    ? null
+    : unsupported(operation, "RETRY");
 }
 
 function unsupported(
   operation: BrowserDataOperation,
+  recovery: "ONLINE_ONLY" | "RETRY",
 ): BrowserFailureResult {
   return asFailure(
-    browserDataFailure("UNSUPPORTED", operation, {
-      recovery: "ONLINE_ONLY",
-    }),
+    browserDataFailure("UNSUPPORTED", operation, { recovery }),
   );
 }
 
diff --git a/tests/unit/public-response-cache.test.ts b/tests/unit/public-response-cache.test.ts
index 9648fa4..4201535 100644
--- a/tests/unit/public-response-cache.test.ts
+++ b/tests/unit/public-response-cache.test.ts
@@ -6,6 +6,7 @@ import type {
 } from "../../src/application/ports/browser-file-storage/cache-storage-ports.ts";
 import {
   createDefaultPublicCachePolicy,
+  resolvePublicCachePolicy,
   type PublicCacheRuntimePolicy,
 } from "../../src/adapters/cache-storage/public-cache-policy.ts";
 import {
@@ -140,6 +141,159 @@ async function manifestFor(
 }
 
 describe("public response Cache Storage adapter", () => {
+  it("rejects a policy that enables variants but strips Vary", () => {
+    const base = createDefaultPublicCachePolicy(
+      "https://assets.example.test",
+    );
+    // STO-03. Enabling variants while dropping Vary from the response
+    // allowlist makes every stored variant collide on the same key.
+    expect(() =>
+      resolvePublicCachePolicy({
+        ...base,
+        allowedRequestHeaderNames: ["accept", "accept-language"],
+        allowedVaryHeaderNames: ["accept-language"],
+        allowedResponseHeaderNames: base.allowedResponseHeaderNames.filter(
+          (name) => name !== "vary",
+        ),
+      }),
+    ).toThrow(TypeError);
+    // The same policy with Vary preserved is accepted.
+    expect(() =>
+      resolvePublicCachePolicy({
+        ...base,
+        allowedRequestHeaderNames: ["accept", "accept-language"],
+        allowedVaryHeaderNames: ["accept-language"],
+      }),
+    ).not.toThrow();
+  });
+
+  it("restages an evicted entry even when the release marker remains", async () => {
+    const policy = createDefaultPublicCachePolicy(
+      "https://assets.example.test",
+    );
+    const bytes = new Uint8Array([9, 9, 9, 9]);
+    const asset: PublicCacheAsset = {
+      absoluteUrl: "https://assets.example.test/evicted.js",
+      expectedByteLength: bytes.byteLength,
+      expectedContentType: "application/javascript",
+      integrity: {
+        algorithm: "SHA-256",
+        digestHex: await digestHex(bytes),
+      },
+    };
+    const cacheStorage = new MemoryCacheStorage();
+    let fetches = 0;
+    const adapter = createPublicResponseCacheAdapter({
+      cacheStorage: cacheStorage as unknown as CacheStorage,
+      crypto: globalThis.crypto,
+      mutationLock: immediateLock,
+      policy,
+      fetcher: async () => {
+        fetches += 1;
+        return new Response(bytes, {
+          headers: {
+            "cache-control": "public",
+            "content-type": "application/javascript",
+          },
+        });
+      },
+    });
+    const manifest = await manifestFor("evicted-release", [asset], policy);
+    expect(await adapter.admin.stageRelease(manifest)).toMatchObject({
+      ok: true,
+    });
+    expect(fetches).toBe(1);
+
+    // The browser evicts the payload but leaves the marker behind.
+    const cacheName = [...cacheStorage.caches.keys()].find((name) =>
+      name.includes("evicted-release"),
+    );
+    if (!cacheName) throw new Error("staged cache missing");
+    const cache = cacheStorage.caches.get(cacheName)!;
+    const payloadIndex = cache.responses.findIndex(
+      (entry) => entry.request.url === asset.absoluteUrl,
+    );
+    expect(payloadIndex).toBeGreaterThanOrEqual(0);
+    cache.responses.splice(payloadIndex, 1);
+
+    // A marker is a claim, not evidence: restaging must repair.
+    expect(await adapter.admin.stageRelease(manifest)).toMatchObject({
+      ok: true,
+    });
+    expect(fetches).toBe(2);
+    expect(
+      await adapter.admin.activateRelease(
+        manifest.releaseRegistryId,
+        manifest.manifestDigestHex,
+      ),
+    ).toMatchObject({ ok: true });
+  });
+
+  it("activates a verified prestaged release without a fetcher", async () => {
+    const policy = createDefaultPublicCachePolicy(
+      "https://assets.example.test",
+    );
+    const bytes = new Uint8Array([4, 4, 4, 4]);
+    const asset: PublicCacheAsset = {
+      absoluteUrl: "https://assets.example.test/offline.js",
+      expectedByteLength: bytes.byteLength,
+      expectedContentType: "application/javascript",
+      integrity: {
+        algorithm: "SHA-256",
+        digestHex: await digestHex(bytes),
+      },
+    };
+    const cacheStorage = new MemoryCacheStorage();
+    const online = createPublicResponseCacheAdapter({
+      cacheStorage: cacheStorage as unknown as CacheStorage,
+      crypto: globalThis.crypto,
+      mutationLock: immediateLock,
+      policy,
+      fetcher: async () =>
+        new Response(bytes, {
+          headers: {
+            "cache-control": "public",
+            "content-type": "application/javascript",
+          },
+        }),
+    });
+    const manifest = await manifestFor("offline-release", [asset], policy);
+    expect(await online.admin.stageRelease(manifest)).toMatchObject({
+      ok: true,
+    });
+
+    // STO-05. Activation and cleanup perform no network I/O, so a missing
+    // fetcher must not make an offline rollback UNSUPPORTED.
+    const offline = createPublicResponseCacheAdapter({
+      cacheStorage: cacheStorage as unknown as CacheStorage,
+      crypto: globalThis.crypto,
+      mutationLock: immediateLock,
+      policy,
+    });
+    expect(
+      await offline.admin.activateRelease(
+        manifest.releaseRegistryId,
+        manifest.manifestDigestHex,
+      ),
+    ).toMatchObject({ ok: true });
+  });
+
+  it("cleans exact owned caches without a fetcher", async () => {
+    const policy = createDefaultPublicCachePolicy(
+      "https://assets.example.test",
+    );
+    const cacheStorage = new MemoryCacheStorage();
+    const offline = createPublicResponseCacheAdapter({
+      cacheStorage: cacheStorage as unknown as CacheStorage,
+      crypto: globalThis.crypto,
+      mutationLock: immediateLock,
+      policy,
+    });
+    expect(await offline.admin.cleanupOwned()).toMatchObject({
+      ok: true,
+    });
+  });
+
   it("stages, re-verifies and atomically activates an exact release", async () => {
     const cacheStorage = new MemoryCacheStorage();
     const bytes = new Uint8Array([1, 2, 3, 4]);