diff --git a/scripts/check-adapter-inventory.ts b/scripts/check-adapter-inventory.ts
index 0091d1c..331f20b 100644
--- a/scripts/check-adapter-inventory.ts
+++ b/scripts/check-adapter-inventory.ts
@@ -133,7 +133,7 @@ async function main(): Promise<void> {
   //
   // 이 목록은 재검토가 이름으로 지목한 네 파일만 덮는다. 같은 두 그룹의
   // `image-cdn-runtime.ts`와 `resumable-upload-runtime.ts`는 여기 없고 지금도
-  // 자기 abort 사본을 들고 있다. 어댑터 전체로는 24개 파일이 그렇다. 그 전수
+  // 자기 abort 사본을 들고 있다. 어댑터 전체로는 23개 파일이 그렇다. 그 전수
   // 이행은 abort 의미론을 바꾸는 별도 작업이라 이 목록으로 강제하지 않고,
   // 아래 래칫이 개수가 늘어나는 것만 막는다.
   const REQUIRED_ABORT_CONSUMERS: readonly string[] = [
@@ -190,12 +190,15 @@ async function main(): Promise<void> {
 
   // 손수 짠 abort 배선은 줄어들기만 해야 한다.
   //
-  // 커널 `platform/abortable-operation.ts`가 있는데도 어댑터 24개 파일이
+  // 커널 `platform/abortable-operation.ts`가 있는데도 어댑터 23개 파일이
   // `addEventListener("abort")`로 같은 race/cleanup을 각자 짠다. 그 전수 이행은
   // 동작이 바뀌는 큰 작업이라 한 번에 하지 않는다. 대신 개수를 여기 고정해
   // 되돌아가지 못하게 한다. 이행으로 숫자가 내려가면 이 상수도 같이 내린다.
   // `platform/`은 커널 자신이므로 세지 않는다.
-  const HAND_ROLLED_ABORT_CEILING = 24;
+  //
+  // 24 → 23: `browser-transfer/resumable-upload/indexeddb-checkpoint-store.ts`가
+  // IndexedDB 커널로 옮겨가면서 자기 abort 리스너를 지웠다.
+  const HAND_ROLLED_ABORT_CEILING = 23;
   const handRolledScan = spawnSync(
     "git",
     ["grep", "-l", 'addEventListener("abort"', "--", "src/adapters"],
diff --git a/src/adapters/browser-transfer/resumable-upload/indexeddb-checkpoint-store.ts b/src/adapters/browser-transfer/resumable-upload/indexeddb-checkpoint-store.ts
index ee95180..1861697 100644
--- a/src/adapters/browser-transfer/resumable-upload/indexeddb-checkpoint-store.ts
+++ b/src/adapters/browser-transfer/resumable-upload/indexeddb-checkpoint-store.ts
@@ -4,12 +4,26 @@ import type {
   ResumableUploadCheckpointStore,
   PartitionDeleteOutcome,
 } from "../../../application/ports/browser-transfer/resumable-upload.ts";
-import type { BrowserDataResult } from "../../../application/ports/browser-file-storage/shared.ts";
+import type {
+  BrowserDataFailure,
+  BrowserDataFailureCode,
+  BrowserDataRecovery,
+  BrowserDataResult,
+} from "../../../application/ports/browser-file-storage/shared.ts";
+import { isBrowserDataFailureCode } from "../../../application/ports/browser-file-storage/shared.ts";
 import {
   browserDataFailure,
   browserDataSuccess,
   mapBrowserDataException,
 } from "../../browser-file-storage/result.ts";
+import { snapshotAbortTimers } from "../../platform/abortable-operation.ts";
+import {
+  createIndexedDbConnection,
+  deleteIndexedDbDatabase,
+  openIndexedDbDatabase,
+  type IndexedDbTranslate,
+} from "../../platform/indexeddb-connection.ts";
+import { runIndexedDbTransaction } from "../../platform/indexeddb-transaction.ts";
 import {
   isResumableUploadCheckpoint,
   SAFE_OPAQUE_ID,
@@ -20,6 +34,7 @@ const DATABASE_VERSION = 1;
 const CHECKPOINT_STORE = "checkpoints";
 const GOVERNANCE_STORE = "governance";
 const GOVERNANCE_KEY = "scope-binding";
+const OPERATION = "UPLOAD_RECONCILE";
 const DEFAULT_BLOCKED_TIMEOUT_MS = 5_000;
 
 /**
@@ -65,10 +80,94 @@ type ScopeBinding = Readonly<{
   partitionToken: string;
 }>;
 
-type OpenFactory = (
-  name: string,
-  version?: number,
-) => IDBOpenDBRequest;
+/**
+ * `browserDataFailure` and `mapBrowserDataException` build a `Result`, while the
+ * kernel's `translate` contract wants the failure on its own. Both only ever
+ * build the failure arm, so the branch below is a narrowing, not a claim.
+ */
+function failureOf(result: BrowserDataResult<never>): BrowserDataFailure {
+  if (result.ok) {
+    throw new TypeError("A browser data failure was expected.");
+  }
+  return result.error;
+}
+
+function checkpointFailure(
+  code: BrowserDataFailureCode,
+  options: Readonly<{
+    retryable?: boolean;
+    recovery?: BrowserDataRecovery;
+  }> = {},
+): BrowserDataFailure {
+  return failureOf(browserDataFailure(code, OPERATION, options));
+}
+
+function mappedFailure(error: unknown): BrowserDataFailure {
+  return failureOf(mapBrowserDataException(error, OPERATION));
+}
+
+/**
+ * The kernel keeps an admission's `detail` opaque, so a rejected scope binding
+ * carries its own failure through it and the guard hands that failure straight
+ * back. Any other shape would mean a second taxonomy grew beside this one.
+ */
+function admissionFailure(detail: unknown): BrowserDataFailure | null {
+  if (!detail || typeof detail !== "object") return null;
+  const record = detail as Record<string, unknown>;
+  return isBrowserDataFailureCode(record.code) && record.operation === OPERATION
+    ? (detail as BrowserDataFailure)
+    : null;
+}
+
+/**
+ * BT-UP-03. The checkpoint store keeps its own failure table rather than the
+ * `mapIndexedDbException` the other three IndexedDB adapters share: the same
+ * native error is a different answer here (a `ConstraintError` recovers by
+ * REOPEN, a quota failure is retryable), and unifying the four tables is a
+ * separate change from moving the mechanics onto the kernel.
+ */
+const translate: IndexedDbTranslate<BrowserDataFailure> = (cause) => {
+  switch (cause.kind) {
+    case "NATIVE_EXCEPTION":
+      return mappedFailure(cause.error);
+    case "NO_VALUE_PRODUCED":
+      // Three adapters call this UNAVAILABLE. Here a checkpoint transaction
+      // that committed without producing a value read a row it could not turn
+      // into a checkpoint, so reconciling is the only way forward; retrying
+      // would read the same row again.
+      return checkpointFailure("CORRUPT_DATA", { recovery: "RECONCILE" });
+    case "BLOCKED":
+    case "BLOCKED_DEADLINE":
+      return checkpointFailure("BLOCKED", {
+        retryable: true,
+        recovery: "RESUME",
+      });
+    case "CALLER_ABORT":
+      return checkpointFailure("ABORTED");
+    case "CLOSED":
+      // A closed handle is not the caller aborting: the upload can resume once
+      // a new store is built over the partition.
+      return checkpointFailure("UNAVAILABLE", { recovery: "RESUME" });
+    case "UPGRADE_REJECTED":
+      // The schema body's own throw is what the caller sees. A rejection with
+      // no detail can only come from a null `newVersion`, which an open request
+      // never reports.
+      return cause.detail === undefined
+        ? checkpointFailure("MIGRATION_FAILED", { recovery: "READ_ONLY" })
+        : mappedFailure(cause.detail);
+    case "ADMISSION_REJECTED":
+      return (
+        admissionFailure(cause.detail) ??
+        checkpointFailure("POLICY_REJECTED", { recovery: "READ_ONLY" })
+      );
+    case "UNSUPPORTED":
+      return checkpointFailure("UNSUPPORTED", { recovery: "READ_ONLY" });
+    default: {
+      const exhaustive: never = cause;
+      return exhaustive;
+    }
+  }
+};
 
 export function uploadCheckpointDatabaseName(
   scope: IndexedDbUploadCheckpointScope,
@@ -104,13 +203,19 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
   ) {
     throw new TypeError("Upload checkpoint blocked timeout is invalid.");
   }
-  const openFactory: OpenFactory | undefined = factory
-    ? factory.open.bind(factory)
-    : undefined;
-  const deleteFactory =
-    factory && typeof factory.deleteDatabase === "function"
-      ? factory.deleteDatabase.bind(factory)
-      : undefined;
+  // X-AUDIT-02. The timer callables are captured once, bound to their receiver,
+  // so replacing a global after composition cannot change how a blocked open or
+  // a blocked deletion already in flight is bounded. The kernel throws at
+  // construction if a positive deadline arrives without them.
+  const timers = snapshotAbortTimers({
+    setTimeout: (callback: () => void, milliseconds: number) =>
+      globalThis.setTimeout(callback, milliseconds),
+    clearTimeout: (handle: ReturnType<typeof globalThis.setTimeout>) => {
+      globalThis.clearTimeout(handle);
+    },
+  });
+  const canDelete =
+    factory !== undefined && typeof factory.deleteDatabase === "function";
   const databaseName = uploadCheckpointDatabaseName(scope);
   const pendingDeletions = pendingDeletionsFor(factory);
   if (pendingDeletions.has(databaseName)) {
@@ -125,118 +230,60 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
     schemaVersion: 1,
     ...scope,
   });
-  let database: IDBDatabase | null = null;
-  let opening: Promise<BrowserDataResult<IDBDatabase>> | null = null;
-  let closed = false;
 
-  async function open(
-    signal?: AbortSignal,
-  ): Promise<BrowserDataResult<IDBDatabase>> {
-    if (closed || !openFactory) {
-      return browserDataFailure("UNAVAILABLE", "UPLOAD_RECONCILE", {
-        recovery: "RESUME",
-      });
-    }
-    if (signal?.aborted) {
-      return browserDataFailure("ABORTED", "UPLOAD_RECONCILE");
-    }
-    if (database) return browserDataSuccess(database);
-    if (!opening) {
-      opening = openAndBind().finally(() => {
-        opening = null;
-      });
-    }
-    const result = await opening;
-    if (signal?.aborted) {
-      return browserDataFailure("ABORTED", "UPLOAD_RECONCILE");
-    }
-    return result;
-  }
-
-  async function openAndBind(): Promise<BrowserDataResult<IDBDatabase>> {
-    let request: IDBOpenDBRequest;
-    try {
-      request = openFactory!(databaseName, DATABASE_VERSION);
-    } catch (error) {
-      return mapBrowserDataException(error, "UPLOAD_RECONCILE");
-    }
-    const opened = await new Promise<BrowserDataResult<IDBDatabase>>(
-      (resolve) => {
-        let settled = false;
-        let blockedTimer: ReturnType<typeof setTimeout> | undefined;
-        const finish = (result: BrowserDataResult<IDBDatabase>) => {
-          if (settled) {
-            if (result.ok) result.value.close();
-            return;
-          }
-          settled = true;
-          if (blockedTimer) clearTimeout(blockedTimer);
-          resolve(result);
-        };
-        request.onupgradeneeded = () => {
-          try {
-            const db = request.result;
-            if (!db.objectStoreNames.contains(CHECKPOINT_STORE)) {
-              db.createObjectStore(CHECKPOINT_STORE, {
-                keyPath: "uploadKey",
-              });
-            }
-            if (!db.objectStoreNames.contains(GOVERNANCE_STORE)) {
-              db.createObjectStore(GOVERNANCE_STORE, {
-                keyPath: "key",
-              });
-            }
-          } catch (error) {
-            try {
-              request.transaction?.abort();
-            } catch {
-              // The open request will surface the original closed failure.
-            }
-            finish(mapBrowserDataException(error, "UPLOAD_RECONCILE"));
-          }
-        };
-        request.onblocked = () => {
-          blockedTimer = setTimeout(() => {
-            finish(
-              browserDataFailure("BLOCKED", "UPLOAD_RECONCILE", {
-                retryable: true,
-                recovery: "RESUME",
-              }),
-            );
-          }, blockedTimeoutMs);
-        };
-        request.onerror = () =>
-          finish(
-            mapBrowserDataException(
-              request.error,
-              "UPLOAD_RECONCILE",
-            ),
-          );
-        request.onsuccess = () => finish(browserDataSuccess(request.result));
-      },
-    );
-    if (!opened.ok) return opened;
-    if (closed) {
-      opened.value.close();
-      return browserDataFailure("UNAVAILABLE", "UPLOAD_RECONCILE", {
-        recovery: "RESUME",
-      });
-    }
-    const bound = await bindScope(opened.value, expectedBinding);
-    if (!bound.ok) {
-      opened.value.close();
-      return bound;
-    }
-    opened.value.onversionchange = () => {
-      opened.value.close();
-      if (database === opened.value) database = null;
-    };
-    opened.value.onclose = () => {
-      if (database === opened.value) database = null;
-    };
-    database = opened.value;
-    return browserDataSuccess(opened.value);
-  }
+  /**
+   * The handle owns the cached connection, the single-flight open and the
+   * `versionchange`/`close` invalidation this file used to wire by hand. No
+   * `onVersionChange` callback is passed because closing the connection and
+   * dropping the cached handle — which the kernel already does — was this
+   * store's entire listener body; registering one inside `admit` instead would
+   * be overwritten when the handle adopts the connection.
+   */
+  const connection = createIndexedDbConnection<BrowserDataFailure>({
+    translate,
+    open: (signal) =>
+      factory === undefined
+        ? Promise.resolve(
+            browserDataFailure("UNAVAILABLE", OPERATION, {
+              recovery: "RESUME",
+            }),
+          )
+        : openIndexedDbDatabase<BrowserDataFailure>({
+            factory,
+            databaseName,
+            version: DATABASE_VERSION,
+            translate,
+            signal,
+            blockedTimeoutMs,
+            timers,
+            upgrade: ({ database }) => {
+              try {
+                if (!database.objectStoreNames.contains(CHECKPOINT_STORE)) {
+                  database.createObjectStore(CHECKPOINT_STORE, {
+                    keyPath: "uploadKey",
+                  });
+                }
+                if (!database.objectStoreNames.contains(GOVERNANCE_STORE)) {
+                  database.createObjectStore(GOVERNANCE_STORE, {
+                    keyPath: "key",
+                  });
+                }
+              } catch (error) {
+                return { kind: "REJECTED", detail: error };
+              }
+              return { kind: "APPLIED" };
+            },
+            // The binding runs before the caller ever sees the connection, so a
+            // partition bound to another scope can never serve a read. A
+            // rejected admission closes the connection inside the kernel.
+            admit: async (database) => {
+              const bound = await bindScope(database, expectedBinding);
+              return bound.ok
+                ? { kind: "ADMIT" }
+                : { kind: "REJECT", detail: bound.error };
+            },
+          }),
+  });
 
   const storeValue: ResumableUploadCheckpointStore = {
     async read(
@@ -246,12 +293,9 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
       BrowserDataResult<ResumableUploadCheckpoint | null>
     > {
       if (!SAFE_UPLOAD_KEY.test(uploadKey)) {
-        return browserDataFailure(
-          "INVALID_INPUT",
-          "UPLOAD_RECONCILE",
-        );
+        return browserDataFailure("INVALID_INPUT", OPERATION);
       }
-      const opened = await open(signal);
+      const opened = await connection.acquire(signal);
       if (!opened.ok) return opened;
       return await runCheckpointTransaction<
         ResumableUploadCheckpoint | null
@@ -261,7 +305,7 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
         signal,
         (nativeStore, context) => {
           const request = nativeStore.get(uploadKey);
-          request.onerror = () => context.nativeFailure(request.error);
+          request.onerror = () => context.fail(mappedFailure(request.error));
           request.onsuccess = () => {
             if (request.result === undefined) {
               context.succeed(null);
@@ -269,11 +313,7 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
             }
             if (!isResumableUploadCheckpoint(request.result)) {
               context.fail(
-                browserDataFailure(
-                  "CORRUPT_DATA",
-                  "UPLOAD_RECONCILE",
-                  { recovery: "RECONCILE" },
-                ),
+                checkpointFailure("CORRUPT_DATA", { recovery: "RECONCILE" }),
               );
               return;
             }
@@ -294,10 +334,7 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
       try {
         checkpoint = snapshotCheckpoint(inputValue.checkpoint);
       } catch {
-        return browserDataFailure(
-          "INVALID_INPUT",
-          "UPLOAD_RECONCILE",
-        );
+        return browserDataFailure("INVALID_INPUT", OPERATION);
       }
       const expectedRevision = inputValue.expectedRevision;
       if (
@@ -306,12 +343,9 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
             expectedRevision < 1)) ||
         checkpoint.revision !== (expectedRevision ?? 0) + 1
       ) {
-        return browserDataFailure(
-          "INVALID_INPUT",
-          "UPLOAD_RECONCILE",
-        );
+        return browserDataFailure("INVALID_INPUT", OPERATION);
       }
-      const opened = await open(inputValue.signal);
+      const opened = await connection.acquire(inputValue.signal);
       if (!opened.ok) return opened;
       return await runCheckpointTransaction<ResumableUploadCheckpoint>(
         opened.value,
@@ -319,7 +353,7 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
         inputValue.signal,
         (nativeStore, context) => {
           const request = nativeStore.get(checkpoint.uploadKey);
-          request.onerror = () => context.nativeFailure(request.error);
+          request.onerror = () => context.fail(mappedFailure(request.error));
           request.onsuccess = () => {
             const current = request.result;
             if (
@@ -329,16 +363,12 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
                   current.revision !== expectedRevision))
             ) {
               context.fail(
-                browserDataFailure(
-                  "CONFLICT",
-                  "UPLOAD_RECONCILE",
-                  { recovery: "RECONCILE" },
-                ),
+                checkpointFailure("CONFLICT", { recovery: "RECONCILE" }),
               );
               return;
             }
             const put = nativeStore.put(checkpoint);
-            put.onerror = () => context.nativeFailure(put.error);
+            put.onerror = () => context.fail(mappedFailure(put.error));
             put.onsuccess = () => context.succeed(checkpoint);
           };
         },
@@ -355,12 +385,9 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
         !Number.isSafeInteger(inputValue.expectedRevision) ||
         inputValue.expectedRevision < 1
       ) {
-        return browserDataFailure(
-          "INVALID_INPUT",
-          "UPLOAD_RECONCILE",
-        );
+        return browserDataFailure("INVALID_INPUT", OPERATION);
       }
-      const opened = await open(inputValue.signal);
+      const opened = await connection.acquire(inputValue.signal);
       if (!opened.ok) return opened;
       return await runCheckpointTransaction<void>(
         opened.value,
@@ -368,24 +395,20 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
         inputValue.signal,
         (nativeStore, context) => {
           const request = nativeStore.get(inputValue.uploadKey);
-          request.onerror = () => context.nativeFailure(request.error);
+          request.onerror = () => context.fail(mappedFailure(request.error));
           request.onsuccess = () => {
             if (
               !isResumableUploadCheckpoint(request.result) ||
               request.result.revision !== inputValue.expectedRevision
             ) {
               context.fail(
-                browserDataFailure(
-                  "CONFLICT",
-                  "UPLOAD_RECONCILE",
-                  { recovery: "RECONCILE" },
-                ),
+                checkpointFailure("CONFLICT", { recovery: "RECONCILE" }),
               );
               return;
             }
             const deletion = nativeStore.delete(inputValue.uploadKey);
             deletion.onerror = () =>
-              context.nativeFailure(deletion.error);
+              context.fail(mappedFailure(deletion.error));
             deletion.onsuccess = () => context.succeed(undefined);
           };
         },
@@ -393,9 +416,7 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
     },
 
     close() {
-      closed = true;
-      database?.close();
-      database = null;
+      connection.close();
     },
   };
   const store = Object.freeze(storeValue);
@@ -405,82 +426,50 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
     ): Promise<
       BrowserDataResult<PartitionDeleteOutcome>
     > {
+      // IDB deleteDatabase cannot be cancelled after dispatch. AbortSignal is
+      // intentionally observed only before dispatch so the adapter never
+      // reports ABORTED while deletion may still commit — which is also why the
+      // kernel's delete takes no signal.
       if (signal?.aborted) {
-        return browserDataFailure("ABORTED", "UPLOAD_RECONCILE");
+        return browserDataFailure("ABORTED", OPERATION);
       }
-      closed = true;
-      database?.close();
-      database = null;
-      if (!deleteFactory) {
-        return browserDataFailure(
-          "UNSUPPORTED",
-          "UPLOAD_RECONCILE",
-          { recovery: "READ_ONLY" },
+      connection.close();
+      if (factory === undefined || !canDelete) {
+        return browserDataFailure("UNSUPPORTED", OPERATION, {
+          recovery: "READ_ONLY",
+        });
+      }
+      // BT-UP-03. Once dispatched the deletion may still commit after this call
+      // returns, so the pending registration is installed before the promise
+      // settles and is only released by the real native completion — which is
+      // exactly what `onSettled` reports and a blocked deadline never does.
+      pendingDeletions.add(databaseName);
+      const deleted = await deleteIndexedDbDatabase<BrowserDataFailure>({
+        factory,
+        databaseName,
+        translate,
+        blockedTimeoutMs,
+        timers,
+        onSettled: () => {
+          pendingDeletions.delete(databaseName);
+        },
+      });
+      if (!deleted.ok) return deleted;
+      if (deleted.value.kind === "DELETED") {
+        return browserDataSuccess(
+          Object.freeze({
+            state: "DELETED" as const,
+            effect: "APPLIED" as const,
+          }),
         );
       }
-      let request: IDBOpenDBRequest;
-      try {
-        request = deleteFactory(databaseName);
-      } catch (error) {
-        return mapBrowserDataException(error, "UPLOAD_RECONCILE");
-      }
-      // BT-UP-03. Once dispatched the deletion may still commit after this
-      // call returns, so the pending registration is installed before the
-      // promise settles and is only released by the real native completion.
-      pendingDeletions.add(databaseName);
-      return await new Promise<BrowserDataResult<PartitionDeleteOutcome>>(
-        (resolve) => {
-          let settled = false;
-          let blockedTimer: ReturnType<typeof setTimeout> | undefined;
-          const finish = (
-            result: BrowserDataResult<PartitionDeleteOutcome>,
-          ) => {
-            if (settled) return;
-            settled = true;
-            if (blockedTimer) clearTimeout(blockedTimer);
-            resolve(result);
-          };
-          const releasePending = () => {
-            pendingDeletions.delete(databaseName);
-          };
-          // IDB deleteDatabase cannot be cancelled after dispatch. AbortSignal
-          // is intentionally observed only before dispatch so the adapter never
-          // reports ABORTED while deletion may still commit.
-          request.onblocked = () => {
-            blockedTimer = setTimeout(() => {
-              // Not NOT_APPLIED: the request is still live in the browser.
-              finish(
-                browserDataSuccess(
-                  Object.freeze({
-                    state: "PENDING" as const,
-                    effect: "UNKNOWN" as const,
-                    reason: "BLOCKED_DEADLINE" as const,
-                  }),
-                ),
-              );
-            }, blockedTimeoutMs);
-          };
-          request.onerror = () => {
-            releasePending();
-            finish(
-              mapBrowserDataException(
-                request.error,
-                "UPLOAD_RECONCILE",
-              ),
-            );
-          };
-          request.onsuccess = () => {
-            releasePending();
-            finish(
-              browserDataSuccess(
-                Object.freeze({
-                  state: "DELETED" as const,
-                  effect: "APPLIED" as const,
-                }),
-              ),
-            );
-          };
-        },
+      // Not NOT_APPLIED: the request is still live in the browser.
+      return browserDataSuccess(
+        Object.freeze({
+          state: "PENDING" as const,
+          effect: "UNKNOWN" as const,
+          reason: "BLOCKED_DEADLINE" as const,
+        }),
       );
     },
   };
@@ -488,168 +477,79 @@ export function createIndexedDbResumableUploadCheckpointRuntime(
   return Object.freeze({ store, admin });
 }
 
-type TransactionContext<Value> = Readonly<{
-  succeed(value: Value): void;
-  fail(result: BrowserDataResult<never>): void;
-  nativeFailure(error: unknown): void;
-}>;
-
+/**
+ * `durability` is deliberately `undefined` rather than `"default"`: that opens
+ * the transaction with no options bag at all, which is what checkpoint writes
+ * have always done. Passing a named value would quietly move them onto a
+ * different flush policy and slow every checkpoint write down.
+ *
+ * A request error goes through `fail`, which aborts, rather than through the
+ * kernel's `requestFailed`, which only records. `compareAndSwap` issues its put
+ * inside the get's success handler, so a transaction left running after a
+ * failed request is a transaction that can still commit half of a swap.
+ */
 async function runCheckpointTransaction<Value>(
   database: IDBDatabase,
-  mode: IDBTransactionMode,
+  mode: "readonly" | "readwrite",
   signal: AbortSignal | undefined,
   execute: (
     store: IDBObjectStore,
-    context: TransactionContext<Value>,
+    context: Readonly<{
+      succeed(value: Value): void;
+      fail(failure: BrowserDataFailure): void;
+    }>,
   ) => void,
 ): Promise<BrowserDataResult<Value>> {
-  if (signal?.aborted) {
-    return browserDataFailure("ABORTED", "UPLOAD_RECONCILE");
-  }
-  return await new Promise<BrowserDataResult<Value>>((resolve) => {
-    let transaction: IDBTransaction;
-    try {
-      transaction = database.transaction(CHECKPOINT_STORE, mode);
-    } catch (error) {
-      resolve(mapBrowserDataException(error, "UPLOAD_RECONCILE"));
-      return;
-    }
-    let value: Value | undefined;
-    let hasValue = false;
-    let failure: BrowserDataResult<never> | null = null;
-    let settled = false;
-    const finish = (result: BrowserDataResult<Value>) => {
-      if (settled) return;
-      settled = true;
-      signal?.removeEventListener("abort", abort);
-      resolve(result);
-    };
-    const abort = () => {
-      const previousFailure = failure;
-      failure = browserDataFailure("ABORTED", "UPLOAD_RECONCILE");
-      try {
-        transaction.abort();
-      } catch {
-        // The transaction may already be durably committed while its
-        // completion event is still queued. Wait for oncomplete/onabort so we
-        // never report ABORTED for a mutation that actually committed.
-        failure = previousFailure;
-      }
-    };
-    signal?.addEventListener("abort", abort, { once: true });
-    transaction.oncomplete = () => {
-      if (!hasValue) {
-        finish(
-          browserDataFailure("CORRUPT_DATA", "UPLOAD_RECONCILE", {
-            recovery: "RECONCILE",
-          }),
-        );
-        return;
-      }
-      finish(browserDataSuccess(value as Value));
-    };
-    transaction.onerror = () => {
-      // onabort is the terminal transaction signal.
-    };
-    transaction.onabort = () =>
-      finish(
-        failure ??
-          mapBrowserDataException(
-            transaction.error,
-            "UPLOAD_RECONCILE",
-          ),
-      );
-    const context: TransactionContext<Value> = Object.freeze({
-      succeed(next) {
-        if (failure) return;
-        value = next;
-        hasValue = true;
-      },
-      fail(result) {
-        if (failure) return;
-        failure = result;
-        try {
-          transaction.abort();
-        } catch {
-          finish(result);
-        }
-      },
-      nativeFailure(error) {
-        if (failure) return;
-        failure = mapBrowserDataException(
-          error,
-          "UPLOAD_RECONCILE",
-        );
-        try {
-          transaction.abort();
-        } catch {
-          finish(failure);
-        }
-      },
-    });
-    try {
+  return await runIndexedDbTransaction<Value, BrowserDataFailure>({
+    database,
+    stores: [CHECKPOINT_STORE],
+    mode,
+    translate,
+    signal,
+    durability: undefined,
+    queue: (transaction, context) => {
       execute(transaction.objectStore(CHECKPOINT_STORE), context);
-    } catch (error) {
-      context.nativeFailure(error);
-    }
+    },
   });
 }
 
+/**
+ * No `signal`: the binding is part of opening the connection, and an open the
+ * caller gave up on is already ended by the kernel's own abort path.
+ */
 async function bindScope(
   database: IDBDatabase,
   expected: ScopeBinding,
 ): Promise<BrowserDataResult<void>> {
-  return await new Promise<BrowserDataResult<void>>((resolve) => {
-    let transaction: IDBTransaction;
-    try {
-      transaction = database.transaction(GOVERNANCE_STORE, "readwrite");
-    } catch (error) {
-      resolve(mapBrowserDataException(error, "UPLOAD_RECONCILE"));
-      return;
-    }
-    let failure: BrowserDataResult<never> | null = null;
-    transaction.onerror = () => {
-      // onabort owns terminal resolution.
-    };
-    transaction.onabort = () =>
-      resolve(
-        failure ??
-          mapBrowserDataException(
-            transaction.error,
-            "UPLOAD_RECONCILE",
-          ),
-      );
-    transaction.oncomplete = () => resolve(browserDataSuccess(undefined));
-    const store = transaction.objectStore(GOVERNANCE_STORE);
-    const request = store.get(GOVERNANCE_KEY);
-    request.onerror = () => {
-      failure = mapBrowserDataException(
-        request.error,
-        "UPLOAD_RECONCILE",
-      );
-      transaction.abort();
-    };
-    request.onsuccess = () => {
-      if (request.result === undefined) {
-        const add = store.add(expected);
-        add.onerror = () => {
-          failure = mapBrowserDataException(
-            add.error,
-            "UPLOAD_RECONCILE",
+  return await runIndexedDbTransaction<void, BrowserDataFailure>({
+    database,
+    stores: [GOVERNANCE_STORE],
+    mode: "readwrite",
+    translate,
+    durability: undefined,
+    queue: (transaction, context) => {
+      const store = transaction.objectStore(GOVERNANCE_STORE);
+      const request = store.get(GOVERNANCE_KEY);
+      request.onerror = () => context.fail(mappedFailure(request.error));
+      request.onsuccess = () => {
+        if (request.result === undefined) {
+          const add = store.add(expected);
+          add.onerror = () => context.fail(mappedFailure(add.error));
+          // The binding is the value: without this the committed transaction
+          // would report NO_VALUE_PRODUCED, which this store reads as
+          // CORRUPT_DATA.
+          add.onsuccess = () => context.succeed(undefined);
+          return;
+        }
+        if (!sameScopeBinding(request.result, expected)) {
+          context.fail(
+            checkpointFailure("POLICY_REJECTED", { recovery: "READ_ONLY" }),
           );
-          transaction.abort();
-        };
-        return;
-      }
-      if (!sameScopeBinding(request.result, expected)) {
-        failure = browserDataFailure(
-          "POLICY_REJECTED",
-          "UPLOAD_RECONCILE",
-          { recovery: "READ_ONLY" },
-        );
-        transaction.abort();
-      }
-    };
+          return;
+        }
+        context.succeed(undefined);
+      };
+    },
   });
 }
 
diff --git a/tests/unit/resumable-upload-checkpoint.test.ts b/tests/unit/resumable-upload-checkpoint.test.ts
index 1034a49..88aca0b 100644
--- a/tests/unit/resumable-upload-checkpoint.test.ts
+++ b/tests/unit/resumable-upload-checkpoint.test.ts
@@ -80,6 +80,155 @@ function deletingFactory(
   } as IDBFactory;
 }
 
+/**
+ * A database the test drives by hand. The memory fake commits or aborts on its
+ * own, so the three places the checkpoint store deliberately disagrees with the
+ * other IndexedDB adapters — a commit that produced no value, a request error
+ * that must abort, and an `abort()` that throws — are only observable here.
+ *
+ * The scope-binding transaction is driven automatically because no test below
+ * is about it; only checkpoint transactions are handed to the test.
+ */
+type ScriptedRequest = {
+  result: unknown;
+  error: DOMException | null;
+  onsuccess: ((event: Event) => unknown) | null;
+  onerror: ((event: Event) => unknown) | null;
+};
+
+type ScriptedTransaction = {
+  abortCalls: number;
+  error: DOMException | null;
+  oncomplete: ((event: Event) => unknown) | null;
+  onerror: ((event: Event) => unknown) | null;
+  onabort: ((event: Event) => unknown) | null;
+  readonly requests: ScriptedRequest[];
+  objectStore(name: string): IDBObjectStore;
+  abort(): void;
+  complete(): void;
+};
+
+function scriptedFactory(
+  options: Readonly<{ abortThrows?: boolean }> = {},
+): Readonly<{
+  factory: IDBFactory;
+  /** One entry per `database.transaction(...)` call, holding its argument count. */
+  transactionArguments: number[];
+  checkpoints: ScriptedTransaction[];
+}> {
+  const transactionArguments: number[] = [];
+  const checkpoints: ScriptedTransaction[] = [];
+
+  const scriptedRequest = (): ScriptedRequest => ({
+    result: undefined,
+    error: null,
+    onsuccess: null,
+    onerror: null,
+  });
+
+  const makeTransaction = (): ScriptedTransaction => {
+    const requests: ScriptedRequest[] = [];
+    const transaction: ScriptedTransaction = {
+      abortCalls: 0,
+      error: null,
+      oncomplete: null,
+      onerror: null,
+      onabort: null,
+      requests,
+      objectStore: () => {
+        const queue = () => {
+          const request = scriptedRequest();
+          requests.push(request);
+          return request as unknown as IDBRequest;
+        };
+        return {
+          get: queue,
+          add: queue,
+          put: queue,
+          delete: queue,
+        } as unknown as IDBObjectStore;
+      },
+      abort() {
+        transaction.abortCalls += 1;
+        if (options.abortThrows === true) {
+          throw new DOMException("Transaction is finished.", "InvalidStateError");
+        }
+        transaction.error = new DOMException("Transaction aborted.", "AbortError");
+        transaction.onerror?.(new Event("error"));
+        transaction.onabort?.(new Event("abort"));
+      },
+      complete() {
+        transaction.oncomplete?.(new Event("complete"));
+      },
+    };
+    return transaction;
+  };
+
+  const database = {
+    close() {},
+    transaction: (...args: unknown[]) => {
+      transactionArguments.push(args.length);
+      const requested = args[0];
+      const names =
+        typeof requested === "string"
+          ? [requested]
+          : [...(requested as Iterable<string>)];
+      const transaction = makeTransaction();
+      if (names.includes("governance")) {
+        queueMicrotask(() => {
+          transaction.requests[0]?.onsuccess?.(new Event("success"));
+          queueMicrotask(() => {
+            transaction.requests[1]?.onsuccess?.(new Event("success"));
+            queueMicrotask(() => {
+              transaction.complete();
+            });
+          });
+        });
+      } else {
+        checkpoints.push(transaction);
+      }
+      return transaction as unknown as IDBTransaction;
+    },
+  } as unknown as IDBDatabase;
+
+  const factory = {
+    open: () => {
+      const request = {
+        result: database,
+        error: null,
+        transaction: null,
+        onsuccess: null,
+        onerror: null,
+        onblocked: null,
+        onupgradeneeded: null,
+      } as unknown as IDBOpenDBRequest;
+      queueMicrotask(() => request.onsuccess?.(new Event("success")));
+      return request;
+    },
+    cmp: () => 0,
+    databases: async () => [],
+  } as unknown as IDBFactory;
+
+  return { factory, transactionArguments, checkpoints };
+}
+
+async function flushTasks(): Promise<void> {
+  for (let tick = 0; tick < 5; tick += 1) {
+    await new Promise<void>((resolve) => {
+      setTimeout(resolve, 0);
+    });
+  }
+}
+
+async function openedCheckpointTransaction(
+  scripted: ReturnType<typeof scriptedFactory>,
+): Promise<ScriptedTransaction> {
+  await flushTasks();
+  const transaction = scripted.checkpoints[0];
+  if (!transaction) throw new Error("no checkpoint transaction was opened");
+  return transaction;
+}
+
 describe("IndexedDB resumable upload checkpoint", () => {
   it("length-prefixes scope tuples so delimiter placement cannot collide", () => {
     const first = uploadCheckpointDatabaseName({
@@ -262,4 +411,112 @@ describe("IndexedDB resumable upload checkpoint", () => {
       error: { code: "ABORTED" },
     });
   });
+
+  // CP-1. Three IndexedDB adapters report a value-less commit as UNAVAILABLE;
+  // this one reports CORRUPT_DATA/RECONCILE because a checkpoint read that
+  // committed while producing nothing means the stored row could not be turned
+  // into a checkpoint, and the caller has to reconcile rather than retry.
+  it("reports a checkpoint commit that produced no value as CORRUPT_DATA", async () => {
+    const scripted = scriptedFactory();
+    const store = createIndexedDbResumableUploadCheckpointStore({
+      scope,
+      factory: scripted.factory,
+    });
+    const pending = store.read("upload_key_01");
+    const transaction = await openedCheckpointTransaction(scripted);
+
+    transaction.complete();
+
+    expect(await pending).toMatchObject({
+      ok: false,
+      error: {
+        code: "CORRUPT_DATA",
+        operation: "UPLOAD_RECONCILE",
+        recovery: "RECONCILE",
+      },
+    });
+  });
+
+  // CP-2. A third argument would be a `{durability}` options bag. An engine
+  // that has never seen the bag treats it differently from no bag at all, so
+  // checkpoint writes stay on whatever the engine defaults to.
+  it("opens checkpoint transactions without a durability options bag", async () => {
+    const scripted = scriptedFactory();
+    const store = createIndexedDbResumableUploadCheckpointStore({
+      scope,
+      factory: scripted.factory,
+    });
+    const pending = store.read("upload_key_01");
+    const transaction = await openedCheckpointTransaction(scripted);
+    transaction.complete();
+    await pending;
+
+    expect(scripted.transactionArguments).toEqual([2, 2]);
+  });
+
+  // CP-3. Recording the error and letting the transaction run on would let
+  // `compareAndSwap`'s put commit after its get had already failed.
+  it("aborts the checkpoint transaction as soon as a request fails", async () => {
+    const scripted = scriptedFactory();
+    const store = createIndexedDbResumableUploadCheckpointStore({
+      scope,
+      factory: scripted.factory,
+    });
+    const pending = store.read("upload_key_01");
+    const transaction = await openedCheckpointTransaction(scripted);
+    const read = transaction.requests[0];
+    if (!read) throw new Error("the checkpoint read queued no request");
+
+    read.error = new DOMException("disk is unreadable", "NotReadableError");
+    read.onerror?.(new Event("error"));
+
+    expect(transaction.abortCalls).toBe(1);
+    expect(await pending).toMatchObject({
+      ok: false,
+      error: { code: "NOT_READABLE", retryable: true, recovery: "REOPEN" },
+    });
+  });
+
+  // CP-4. The transaction can already be durably committed while its completion
+  // event is still queued, which is when `abort()` throws. Claiming the abort
+  // would report a committed checkpoint as ABORTED.
+  it("keeps a committed checkpoint when the abort call itself throws", async () => {
+    const scripted = scriptedFactory({ abortThrows: true });
+    const store = createIndexedDbResumableUploadCheckpointStore({
+      scope,
+      factory: scripted.factory,
+    });
+    const controller = new AbortController();
+    const stored = checkpoint(1);
+    const pending = store.read(stored.uploadKey, controller.signal);
+    const transaction = await openedCheckpointTransaction(scripted);
+    const read = transaction.requests[0];
+    if (!read) throw new Error("the checkpoint read queued no request");
+
+    read.result = stored;
+    read.onsuccess?.(new Event("success"));
+    controller.abort();
+    expect(transaction.abortCalls).toBe(1);
+    transaction.complete();
+
+    expect(await pending).toEqual({ ok: true, value: stored });
+  });
+
+  // CP-5. The blocked deadline is the only bound on an open that another
+  // context is holding up, so it has to fire from the scheduler the store was
+  // built with rather than leave the read pending forever.
+  it("bounds a blocked open with the configured deadline", async () => {
+    const memory = new MemoryIndexedDbFactory();
+    const store = createIndexedDbResumableUploadCheckpointStore({
+      scope,
+      factory: memory.factory,
+      blockedTimeoutMs: 1,
+    });
+    memory.blockNextOpen();
+
+    expect(await store.read("upload_key_01")).toMatchObject({
+      ok: false,
+      error: { code: "BLOCKED", retryable: true, recovery: "RESUME" },
+    });
+  });
 });