feat(durable): IndexedDbStorage, a browser storage backed by IndexedDB (@earendil-works/pi-durable/storage/indexeddb)

package-lock.json

@@ -3615,6 +3615,16 @@
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 			"license": "MIT"
 		},
+		"node_modules/fake-indexeddb": {
+			"version": "6.2.6",
+			"resolved": "https://registry.npmjs.org/fake-indexeddb/-/fake-indexeddb-6.2.6.tgz",
+			"integrity": "sha512-ihhmr0KoET51jT8R4YhbUYuLLvr1qqO6INISygtN16i8loR8kAxtAUr4+EKHTSMjL+lggaAn4OC7DRqzrNgnuQ==",
+			"dev": true,
+			"license": "Apache-2.0",
+			"engines": {
+				"node": ">=18"
+			}
+		},
 		"node_modules/fast-deep-equal": {
 			"version": "3.1.3",
 			"resolved": "https://registry.npmjs.org/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz",
@@ -6363,6 +6373,7 @@
 			},
 			"devDependencies": {
 				"@cloudflare/vitest-plugin": "1.4.4",
+				"fake-indexeddb": "6.2.6",
 				"shx": "0.3.4",
 				"vitest": "4.1.11"
 			},

packages/durable/CHANGELOG.md

@@ -13,6 +13,7 @@
 
 ### Added
 
+- Added `IndexedDbStorage` (`@earendil-works/pi-durable/storage/indexeddb`), a browser storage backed by IndexedDB.
 - `HarnessOptions.telemetry` emits the content-free `DURABLE_TELEMETRY_SCHEMA`: public submission admission spans, task phase spans (including extension tasks), committed entry and submission events, running phase-change checkpoints, and nested-tool replay events. Optional propagation stores opaque carriers on submissions and tasks so queued inputs and reopened tasks retain their trace; `TaskOptions.trace` accepts a carrier override or `"root"` (absence inherits the creator's carrier); creation-time `links` connect inputs sharing a run, while steer admissions link to the running trace. Internal admissions emit events without a submit span. Optional metrics record phase duration and live task counts. Failed phases record fixed error-status categories (`task_faulted`, `task_failed`, `task_orphaned`) and diagnostics capped at 500 characters; aborted phases keep status `ok`. Every `onReport` report also emits a fixed-field `pi.durable.report` event on its current span (dropped by the NOOP span when there is none), plus a `pi.durable.reports` counter by type; report telemetry contains no error payload and leaves the callback unchanged. Clock failures report without a phase context. Generation and compaction forward their phase context to pi-ai requests.
 - `settings.compaction.modelOverrides` sets compaction thresholds per model, keyed by exact `"provider/modelId"`, so one harness can serve small- and large-window models; the threshold check, overflow recovery, and the compaction task use the entry of the model they act for ([#10942](https://github.com/earendil-works/pi/issues/10942)).
 - Durable sleeps: a sleeping task holds no invocation, survives restarts, and resumes at its checkpoint once the Harness clock reaches `until`.

packages/durable/README.md

@@ -759,10 +759,15 @@ const usage = await harness.usage(context); // { models: { "openai/gpt-6-sol": U
 | Backend | Import | Notes |
 |---|---|---|
 | Memory | `MemoryStorage` from the package root | Nothing is persisted. |
+| IndexedDB | `IndexedDbStorage.open(name)` from `@earendil-works/pi-durable/storage/indexeddb` | Browser-only storage in one IndexedDB database. |
 | SQLite | `openNodeSqliteStorage(file)` from `@earendil-works/pi-durable/storage/sqlite/node` | One database file. WAL mode with `synchronous = NORMAL`: commits survive process crashes; the newest may be lost on power or host failure. |
 | JSONL | `openNodeJsonlStorage(directory, context)` from `@earendil-works/pi-durable/storage/jsonl/node` | Append-only files in one directory. Pass `{ fsync: true }` to flush before each commit marker. Keeps the whole history in memory too, so memory grows with it; use SQLite for long-running agents. |
 | Cloudflare Durable Object | `openDurableObjectSqliteStorage(ctx.storage)` from `@earendil-works/pi-durable/storage/sqlite/cloudflare` | The SQLite storage of one SQLite-backed Durable Object; commits are its storage transactions. |
 
+In a browser, open IndexedDB storage with `await IndexedDbStorage.open(name)`. One owner must hold the database at a
+time; use a [Web Lock](https://developer.mozilla.org/docs/Web/API/Web_Locks_API) around its lifetime rather than opening
+it in competing tabs or workers. Call `await navigator.storage.persist()` when durable retention matters.
+
 SQLite storage can namespace its tables and indexes when sharing a database: pass `{ prefix: "pi_" }` to
 `SqliteStorage.open(database, options)`, `openNodeSqliteStorage(path, options)`, or
 `openDurableObjectSqliteStorage(ctx.storage, options)`. Storage renders the prefixed names into its SQL, so adapters

packages/durable/package.json

@@ -66,6 +66,12 @@
 			"import": "./dist/storage/memory.js",
 			"default": "./dist/storage/memory.js"
 		},
+		"./storage/indexeddb": {
+			"source": "./src/storage/indexeddb.ts",
+			"types": "./dist/storage/indexeddb.d.ts",
+			"import": "./dist/storage/indexeddb.js",
+			"default": "./dist/storage/indexeddb.js"
+		},
 		"./storage/jsonl": {
 			"source": "./src/storage/jsonl/index.ts",
 			"types": "./dist/storage/jsonl/index.d.ts",
@@ -154,6 +160,7 @@
 	},
 	"devDependencies": {
 		"@cloudflare/vitest-plugin": "1.4.4",
+		"fake-indexeddb": "6.2.6",
 		"shx": "0.3.4",
 		"vitest": "4.1.11"
 	}

packages/durable/test/indexeddb-storage.test.ts

@@ -0,0 +1,282 @@
+/// <reference lib="dom" />
+
+import type { Context, JsonValue } from "@earendil-works/chord";
+import { BACKGROUND_CONTEXT } from "@earendil-works/chord/context";
+import { registerStorageConformance } from "@earendil-works/pi-durable/testing";
+import { IDBKeyRange as FakeIDBKeyRange, IDBFactory } from "fake-indexeddb";
+import { describe, expect, it } from "vitest";
+import { idFromNumber } from "../src/ids.ts";
+import { IndexedDbStorage } from "../src/storage/indexeddb.ts";
+import type {
+	ConversationId,
+	DocumentCreate,
+	DocumentId,
+	EntryId,
+	Id,
+	Seq,
+	Storage,
+	StorageWrite,
+	SubmissionId,
+	TaskId,
+	TaskRecord,
+} from "../src/types.ts";
+import { ROOT_CONVERSATION_ID } from "../src/types.ts";
+
+Object.defineProperty(globalThis, "IDBKeyRange", { configurable: true, value: FakeIDBKeyRange });
+
+const context = BACKGROUND_CONTEXT;
+type StoredTask = TaskRecord<JsonValue, JsonValue, JsonValue>;
+
+class ReopeningStorage implements Storage {
+	private current: IndexedDbStorage;
+	private readonly name: string;
+	private readonly indexedDB: IDBFactory;
+	private closed = false;
+
+	constructor(current: IndexedDbStorage, name: string, indexedDB: IDBFactory) {
+		this.current = current;
+		this.name = name;
+		this.indexedDB = indexedDB;
+	}
+
+	async commit(writes: readonly StorageWrite[], commitContext: Context): Promise<Seq> {
+		if (this.closed) return this.current.commit(writes, commitContext);
+		try {
+			return await this.current.commit(writes, commitContext);
+		} finally {
+			await this.current.close(context);
+			this.current = await IndexedDbStorage.open(this.name, { indexedDB: this.indexedDB });
+		}
+	}
+
+	mintId<I extends Id<string>>(): Promise<I> {
+		return this.current.mintId<I>();
+	}
+	conversation: Storage["conversation"] = (id, readContext) => this.current.conversation(id, readContext);
+	scanConversations: Storage["scanConversations"] = (query, limit, cursor, readContext) =>
+		this.current.scanConversations(query, limit, cursor, readContext);
+	entry(id: EntryId, readContext: Context): ReturnType<Storage["entry"]>;
+	entry(conversationId: ConversationId, id: EntryId, readContext: Context): ReturnType<Storage["entry"]>;
+	entry(idOrConversationId: EntryId | ConversationId, idOrContext: EntryId | Context, readContext?: Context) {
+		if (readContext === undefined) {
+			return this.current.entry(idFromNumber<EntryId>(idOrConversationId), idOrContext as Context);
+		}
+		if (typeof idOrContext !== "number") throw new TypeError("Storage.entry() requires an entry ID");
+		return this.current.entry(
+			idFromNumber<ConversationId>(idOrConversationId),
+			idFromNumber<EntryId>(idOrContext),
+			readContext,
+		);
+	}
+	findLatestHeadMarker: Storage["findLatestHeadMarker"] = (conversationId, at, readContext) =>
+		this.current.findLatestHeadMarker(conversationId, at, readContext);
+	scanEntries: Storage["scanEntries"] = (query, limit, cursor, readContext) =>
+		this.current.scanEntries(query, limit, cursor, readContext);
+	task: Storage["task"] = (id, readContext) => this.current.task(id, readContext);
+	scanTasks: Storage["scanTasks"] = (query, limit, cursor, readContext) =>
+		this.current.scanTasks(query, limit, cursor, readContext);
+	submission: Storage["submission"] = (id, readContext) => this.current.submission(id, readContext);
+	scanSubmissions: Storage["scanSubmissions"] = (query, limit, cursor, readContext) =>
+		this.current.scanSubmissions(query, limit, cursor, readContext);
+	submissionByRequest: Storage["submissionByRequest"] = (conversationId, requestId, readContext) =>
+		this.current.submissionByRequest(conversationId, requestId, readContext);
+	findDocument: Storage["findDocument"] = (address, at, readContext) =>
+		this.current.findDocument(address, at, readContext);
+	document: Storage["document"] = (id, at, readContext) => this.current.document(id, at, readContext);
+	scanDocuments: Storage["scanDocuments"] = (query, limit, cursor, readContext) =>
+		this.current.scanDocuments(query, limit, cursor, readContext);
+
+	async close(closeContext: Context): Promise<void> {
+		if (this.closed) return;
+		this.closed = true;
+		await this.current.close(closeContext);
+	}
+}
+
+async function withStorage(use: (storage: Storage) => Promise<void>): Promise<void> {
+	const indexedDB = new IDBFactory();
+	const storage = await IndexedDbStorage.open("conformance", { indexedDB });
+	try {
+		await use(storage);
+	} finally {
+		await storage.close(context);
+	}
+}
+
+registerStorageConformance({ describe, expect, it }, "IndexedDbStorage", withStorage);
+
+registerStorageConformance({ describe, expect, it }, "IndexedDbStorage across reopen", async (use) => {
+	const indexedDB = new IDBFactory();
+	const name = "reopening-conformance";
+	const created = await IndexedDbStorage.open(name, { indexedDB });
+	await created.close(context);
+	const storage = new ReopeningStorage(await IndexedDbStorage.open(name, { indexedDB }), name, indexedDB);
+	try {
+		await use(storage);
+	} finally {
+		await storage.close(context);
+	}
+});
+
+function pendingTask(id: TaskId<JsonValue>, conversationId = ROOT_CONVERSATION_ID): StoredTask {
+	return {
+		id,
+		conversationId,
+		kind: "test.task",
+		version: 1,
+		input: null,
+		state: { status: "pending", checkpoint: { phase: "ready" } },
+		background: false,
+		abortRequested: false,
+	};
+}
+
+async function createRoot(storage: Storage): Promise<void> {
+	await storage.commit([{ type: "conversation", value: { id: ROOT_CONVERSATION_ID } }], context);
+}
+
+it("persists minted IDs across reopen", async () => {
+	const indexedDB = new IDBFactory();
+	const storage = await IndexedDbStorage.open("mint-reopen", { indexedDB });
+	expect(await storage.mintId<EntryId>()).toBe(2);
+	await storage.close(context);
+	const reopened = await IndexedDbStorage.open("mint-reopen", { indexedDB });
+	try {
+		expect(await reopened.mintId<EntryId>()).toBe(3);
+	} finally {
+		await reopened.close(context);
+	}
+});
+
+it("rolls back table writes when a later document copy fails", async () => {
+	const indexedDB = new IDBFactory();
+	const storage = await IndexedDbStorage.open("atomic-copy", { indexedDB });
+	try {
+		await createRoot(storage);
+		const sourceId = await storage.mintId<DocumentId>();
+		const source = {
+			id: sourceId,
+			kind: "source",
+			scope: { kind: "conversation", conversationId: ROOT_CONVERSATION_ID },
+			history: "rewindable",
+			fork: "asOf",
+		} satisfies DocumentCreate;
+		await storage.commit(
+			[{ type: "document.create", record: source, content: { kind: "base", version: 1, value: { count: 1 } } }],
+			context,
+		);
+		const taskId = await storage.mintId<TaskId<JsonValue>>();
+		const copyId = await storage.mintId<DocumentId>();
+		await expect(
+			storage.commit(
+				[
+					{ type: "task", value: pendingTask(taskId) },
+					{
+						type: "document.copy",
+						record: { ...source, id: copyId, kind: "mismatch" },
+						source: { id: sourceId, at: "current" },
+					},
+				],
+				context,
+			),
+		).rejects.toThrow("was rejected");
+		expect(await storage.task(taskId, context)).toBeUndefined();
+		expect(await storage.document(copyId, "current", context)).toBeUndefined();
+	} finally {
+		await storage.close(context);
+	}
+});
+
+it("scans entries and head markers through fork ancestry", async () => {
+	const indexedDB = new IDBFactory();
+	const storage = await IndexedDbStorage.open("fork-ancestry", { indexedDB });
+	try {
+		await createRoot(storage);
+		const rootFirst = await storage.mintId<EntryId>();
+		const rootMarker = await storage.mintId<EntryId>();
+		await storage.commit(
+			[
+				{ type: "entry", value: { id: rootFirst, conversationId: ROOT_CONVERSATION_ID, kind: "first" } },
+				{
+					type: "entry",
+					value: {
+						id: rootMarker,
+						conversationId: ROOT_CONVERSATION_ID,
+						kind: "marker",
+						head: rootFirst,
+					},
+				},
+			],
+			context,
+		);
+		const childId = await storage.mintId<ConversationId>();
+		await storage.commit(
+			[
+				{
+					type: "conversation",
+					value: { id: childId, parent: { conversationId: ROOT_CONVERSATION_ID, at: rootMarker } },
+				},
+			],
+			context,
+		);
+		const childEntry = await storage.mintId<EntryId>();
+		await storage.commit(
+			[{ type: "entry", value: { id: childEntry, conversationId: childId, kind: "child" } }],
+			context,
+		);
+		expect(
+			(await storage.scanEntries({ conversationId: childId }, 10, undefined, context)).items.map(({ id }) => id),
+		).toEqual([childEntry, rootMarker, rootFirst]);
+		expect((await storage.findLatestHeadMarker(childId, undefined, context))?.id).toBe(rootMarker);
+	} finally {
+		await storage.close(context);
+	}
+});
+
+it("keeps one readwrite transaction active through many mixed writes", async () => {
+	const indexedDB = new IDBFactory();
+	const storage = await IndexedDbStorage.open("large-commit", { indexedDB });
+	try {
+		await createRoot(storage);
+		const writes: StorageWrite[] = [];
+		let lastEntryId: EntryId | undefined;
+		let lastTaskId: TaskId<JsonValue> | undefined;
+		let lastSubmissionId: SubmissionId | undefined;
+		let lastDocumentId: DocumentId | undefined;
+		for (let index = 0; index < 40; index++) {
+			lastEntryId = await storage.mintId<EntryId>();
+			lastTaskId = await storage.mintId<TaskId<JsonValue>>();
+			lastSubmissionId = await storage.mintId<SubmissionId>();
+			lastDocumentId = await storage.mintId<DocumentId>();
+			writes.push(
+				{
+					type: "entry",
+					value: { id: lastEntryId, conversationId: ROOT_CONVERSATION_ID, kind: "bulk", data: { index } },
+				},
+				{ type: "task", value: pendingTask(lastTaskId) },
+				{
+					type: "submission",
+					value: {
+						id: lastSubmissionId,
+						conversationId: ROOT_CONVERSATION_ID,
+						requestId: `bulk-${index}`,
+						type: "input",
+						status: "queued",
+					},
+				},
+				{
+					type: "document.create",
+					record: { id: lastDocumentId, kind: "bulk", key: String(index), scope: { kind: "session" } },
+					content: { kind: "base", version: 1, value: { index } },
+				},
+			);
+		}
+		await storage.commit(writes, context);
+		expect((await storage.entry(lastEntryId!, context))?.entry.data).toEqual({ index: 39 });
+		expect(await storage.task(lastTaskId!, context)).toEqual(pendingTask(lastTaskId!));
+		expect((await storage.submission(lastSubmissionId!, context))?.requestId).toBe("bulk-39");
+		expect((await storage.document(lastDocumentId!, "current", context))?.value).toEqual({ index: 39 });
+	} finally {
+		await storage.close(context);
+	}
+});