feat(ai-persistence): session stores for inputs, credentials, a log, leases, work claims, and a session index

.changeset/persistence-session-stores.md

@@ -0,0 +1,16 @@
+---
+'@tanstack/ai-persistence': minor
+---
+
+Add opt-in session stores. The chat and generation middleware work as before without them.
+
+- `inbox` (`InboxStore`): the inputs a host accepted, with an idempotent `append` by `inputId`, `listPending`, `markApplied`, `markRejected`, and `get`.
+- `credentials` (`CredentialStore`): API keys and OAuth tokens by scope and id. An `oauth` credential can keep the OAuth `client` it was issued to. `list` never returns secret values.
+- `log` (`LogStore`): an append-only log per thread. `append` writes a batch at a position, all or nothing, and rejects with `LogConflictError` when another writer took that position. `read` and `subscribe` complete it. `memoryLogStore()` is the reference store. It is not part of `memoryPersistence()`.
+- `leases` (`LeaseStore`, `TurnLease`, `TurnLeaseKey`): turn leases from a system that already has them.
+- `workClaims` (`WorkClaimStore`): claims on threads that have pending work, with `claim`, `release`, and `listExpired`.
+- `sessions` (`SessionIndexStore`): one index entry per thread, with `upsert`, `get`, `list`, and `delete`. `list` filters by parent thread, owner, title `search`, `harness` name, and exact `metadata` values, and pages with a cursor. The optional `getVersioned` and `upsertIf` give compare-and-set writes.
+
+`defineInboxStore`, `defineCredentialStore`, `defineLogStore`, `defineWorkClaimStore`, and `defineSessionIndexStore` type an adapter. `memoryPersistence()` now also has `inbox`, `credentials`, `workClaims`, and `sessions`. `runPersistenceConformance` runs the cases of each session store when the store is present, so an existing backend needs no `skip` entry.
+
+With `stores.sessions`, `withPersistence` writes one index entry for each subagent child (`subagent:<runId>`), with the parent thread, the tool call, and the owner and `harness` name of the parent entry.

docs/config.json

@@ -712,7 +712,7 @@
           "label": "Build Your Own Adapter",
           "to": "persistence/build-your-own-adapter",
           "addedAt": "2026-08-04",
-          "updatedAt": "2026-09-29"
+          "updatedAt": "2026-10-13"
         },
         {
           "label": "Migrations",

docs/persistence/build-your-own-adapter.md

@@ -189,6 +189,11 @@ The optional run methods are `listByThread`, `listByParentRun`, and
 `skipMethods`. An omitted `listByParentRun` needs no entry: the subagent checks
 skip on their own.
 
+The session stores (`inbox`, `credentials`, `log`, `workClaims`, `sessions`) are
+opt-in too. Their cases run only when your persistence has the store, so a backend
+without them needs no `skip` entry. See the
+[session stores](./store-reference#session-stores) for their rules.
+
 ### Turn on the newer checks
 
 Some checks were added after the suite shipped. They are off by default, so an