diff --git a/.project/concepts/app-contract/_debt.md b/.project/concepts/app-contract/_debt.md
new file mode 100644
index 0000000..9e3ef19
--- /dev/null
+++ b/.project/concepts/app-contract/_debt.md
@@ -0,0 +1,13 @@
+# Doc-debt — app-contract
+
+> Presence of a block = doc to update. Processed → delete the block; no blocks left → delete this file.
+> One block = one "big change": `why` + `files` + `verify` (leaves to review).
+
+## Raw markers (consolidate into blocks, then delete)
+- TOUCHED packages/polyfill/src/surface/docs.ts @2026-08-14 (session f93872b5-293a-4916-a353-181409a96d42)
+- TOUCHED packages/polyfill/src/surface/read-model.ts @2026-08-14 (session f93872b5-293a-4916-a353-181409a96d42)
+- TOUCHED packages/polyfill/src/surface/inbox.ts @2026-08-14 (session f93872b5-293a-4916-a353-181409a96d42)
+- TOUCHED packages/polyfill/src/surface/subscribe.ts @2026-08-14 (session f93872b5-293a-4916-a353-181409a96d42)
+- TOUCHED packages/polyfill/src/surface/ng-proxy.ts @2026-08-14 (session f93872b5-293a-4916-a353-181409a96d42)
+- TOUCHED packages/polyfill/src/index.ts @2026-08-14 (session f93872b5-293a-4916-a353-181409a96d42)
+- TOUCHED docs/api-contract.md @2026-08-14 (session f93872b5-293a-4916-a353-181409a96d42)
diff --git a/.project/concepts/app-contract/contract_polyfill-surface.md b/.project/concepts/app-contract/contract_polyfill-surface.md
index b2ffaad..efdc269 100644
--- a/.project/concepts/app-contract/contract_polyfill-surface.md
+++ b/.project/concepts/app-contract/contract_polyfill-surface.md
@@ -61,9 +61,14 @@ export function subscribeDocs(nuris: NuriLike[], onChange: (r: DocChange, t: Doc
 
 // ── low-level document / SPARQL primitives ───────────────────────────────
 export const docs: {
-  docCreate(sessionId: string, crdt: string, cls: string, dest: string, store?: unknown): Promise<Nuri>;
-  sparqlQuery(sessionId: string, query: string, base?: string, anchor?: NuriLike, label?: string): Promise<unknown>;
-  sparqlUpdate(sessionId: string, query: string, anchor?: NuriLike, label?: string): Promise<void>;
+  // `sessionId` is `string | number` — upstream's own declared type (`Session.session_id`).
+  // It is RELAYED, never converted: the wasm side deserializes a `u64`, and stringifying it
+  // fails for real (`Deserialization error of session_id JsValue("1")`).
+  docCreate(sessionId: string | number, crdt: string, cls: string, dest: string, store?: unknown): Promise<Nuri>;
+  sparqlQuery(sessionId: string | number, query: string, base?: string, anchor?: NuriLike, label?: string): Promise<unknown>;
+  // Returns the commits the update produced, as upstream does (it typed this `void` until
+  // 2026-08-14 while already relaying the value). A caller that ignores it is unaffected.
+  sparqlUpdate(sessionId: string | number, query: string, anchor?: NuriLike, label?: string): Promise<unknown>;
 };
 
 // ── inbox: giving to read, and depositing ────────────────────────────────
@@ -76,12 +81,15 @@ export const inbox: {
   readSynced(targetInbox: NuriLike): Promise<Deposit[]>;
   processInbox(targetInbox: NuriLike): Promise<Deposit[]>;
   watch(targetInbox: NuriLike, onDeposits: (d: Deposit[]) => void): () => void;
-  materialize: typeof read;
+  // `materialize` (a second published name for `read`) was REMOVED on 2026-08-14 —
+  // an alias with no call site, and no counterpart upstream. Use `read`.
 };
 export interface Deposit { from: PrincipalId | null; payload: unknown; ts: number }
 
 // ── the wrapped SDK objects ──────────────────────────────────────────────
-export const ng: Record<string, any>;   // call this instead of the `ng` passed to `configure`
+export const ng: NG;                    // call this instead of the `ng` passed to `configure`
+                                        // `NG` is upstream's own type (`@ng-org/web`), 88 typed
+                                        // members; it was `Record<string, any>` until 2026-08-14
 export function init(...args: any[]): any;      // likewise — not the `init` passed to `configure`
 export function initNg(...args: any[]): any;
 ```
diff --git a/.project/concepts/sign-in/_debt.md b/.project/concepts/sign-in/_debt.md
index 834742c..f16361b 100644
--- a/.project/concepts/sign-in/_debt.md
+++ b/.project/concepts/sign-in/_debt.md
@@ -5,3 +5,5 @@
 
 ## Raw markers (consolidate into blocks, then delete)
 - TOUCHED packages/polyfill/src/shared-wallet/account-registry.ts @2026-08-13 (session f93872b5-293a-4916-a353-181409a96d42)
+- TOUCHED packages/polyfill/src/shared-wallet/physical.ts @2026-08-14 (session f93872b5-293a-4916-a353-181409a96d42)
+- TOUCHED packages/polyfill/src/shared-wallet/session.ts @2026-08-14 (session f93872b5-293a-4916-a353-181409a96d42)
diff --git a/docs/api-contract.md b/docs/api-contract.md
index c921f2e..5c88cb1 100644
--- a/docs/api-contract.md
+++ b/docs/api-contract.md
@@ -135,19 +135,19 @@ Why it lives here and not in the consumer application: the first consumer had ~3
 ### Today — `@ng-eventually/polyfill`
 
 ```ts
-// index.ts:55
-export const ng: Record<string, any>;
-// type re-export, index.ts:50
+// index.ts:152
+export const ng: NG;
+// type re-export, index.ts:86
 export type { NG } from "@ng-org/web";
 ```
 
-`ng` is a `Proxy` (`ng-proxy.ts:10`) forwarding every property to the injected real `ng`, overriding exactly two things: `login` / `session_start` (currently a passthrough with a TODO for shared-wallet credentials) and `sparql_update` (the emulated write-cap guard, rejecting a write when a write policy governs the anchored document and the current user lacks the cap).
+`ng` is a `Proxy` (`ng-proxy.ts:26`) forwarding every property to the injected real `ng`, overriding exactly one thing: `sparql_update` (the emulated write-cap guard, rejecting a write when a write policy governs the anchored document and the current user lacks the cap). `session_start` is intercepted but is a pure passthrough today, with a TODO for shared-wallet credentials. (`login` was named here until 2026-08-14 but has not existed since 2026-08-03: `@ng-org/web` exposes no such method, and the proxy was FABRICATING it.)
 
 ### Target
 
-**PASSTHROUGH (level 2, VERIFIED).** `export declare const ng: NG` with `NG = typeof NGModule`, 77 exported members (`index.d.ts:136-231`). The surface is identical by construction — the proxy adds no member and removes none.
+**PASSTHROUGH (level 2, VERIFIED).** `export declare const ng: NG` with `NG = typeof NGModule`, **88** exported members (`index.d.ts:136-231`; the namespace body is `:140-231`). The surface is identical by construction — the proxy adds no member and removes none — **and identical at the type level too since 2026-08-14**, when the published `ng` stopped being declared `Record<string, any>` and took `NG`, upstream's own type. That escape hatch silently dropped all 88 signatures: an application got no completion, and a misspelt member typechecked.
 
-The two overrides:
+The overrides:
 
 - `session_start(wallet_name: string, user_id: any): Promise<any>` (`index.d.ts:276`) — target signature unchanged; only the emulated credential injection disappears.
 - `sparql_update(session_id: any, sparql: string, nuri: any): Promise<any>` (`index.d.ts:297`) — target signature unchanged. The native enforcement the guard stands in for is the engine's permission model (`verify_perm`, `engine/repo/src/commit.rs:897`), which today is **called only from tests** (its enclosing `Commit::verify` has no runtime caller — see `docs/nextgraph-current-state.md` § *Author-signature verification*). That absence says nothing about the target: write permissions are the engine's declared model, so the guard's *behaviour* (a refused write) is target-shaped even though its *mechanism* (a JS-side check) is emulation. Known limit, documented in `README.md`: the guard fires only on this proxy, and the lib's own writers call the injected `ng` directly, so it is best-effort until cap-enforcement.
@@ -276,24 +276,24 @@ The anchored-read mechanics are level-1 VERIFIED: an anchor restricts the query
 ### Today — `@ng-eventually/polyfill` (namespace `docs`)
 
 ```ts
-// docs.ts:46
+// docs.ts:53
 export async function docCreate(
-  sessionId: string,
+  sessionId: string | number,
   crdt: string,
   cls: string,
   dest: string,
   store?: unknown,
 ): Promise<Nuri>;
-// docs.ts:85
+// docs.ts:101
 export async function sparqlUpdate(
-  sessionId: string,
+  sessionId: string | number,
   query: string,
   anchor?: Nuri,
   label = "sparqlUpdate",
-): Promise<void>;
-// docs.ts:130
+): Promise<unknown>;
+// docs.ts:146
 export async function sparqlQuery(
-  sessionId: string,
+  sessionId: string | number,
   query: string,
   base?: string,
   anchor?: Nuri,
@@ -309,7 +309,12 @@ export async function sparqlQuery(
 
 ### Target
 
-**PASSTHROUGH (level 2, VERIFIED)** — these mirror the real methods 1:1 minus the trailing `label` (a lib-internal access-log tag, never forwarded):
+**PASSTHROUGH (level 2, VERIFIED)** — these forward to the real methods, and the ONLY argument they do not pass on is the trailing `label` (a lib-internal access-log tag). Until 2026-08-14 this entry claimed a 1:1 mirror, which was false in two ways, both now fixed rather than documented as deltas:
+
+- **The session id is `string | number`, upstream's own declared type for it** (`Session.session_id`, `sdk/js/web/src/index.ts:16` and the installed `index.d.ts:266`) — it used to be narrowed to `string` here, which made the value the SDK hands an application impossible to pass back into this library. It is RELAYED, never converted: the wasm side deserializes a `u64` (`sdk/js/lib-wasm/src/lib.rs:352-358` `sparql_query`, `:452-457` `sparql_update`, `:1575` `doc_create`), and stringifying it fails that deserialization for real — observed as `Deserialization error of session_id JsValue("1")`.
+- **`sparqlUpdate` returns what the real method returns** — the commits the update produced (`lib.rs:481-483` serialises `AppResponseV0::Commits`; the installed `index.d.ts:297` types it `Promise<any>`). It was declared `Promise<void>` while already relaying the value at runtime, so the answer was thrown away for every caller. Typed `unknown` rather than `any`, exactly as `sparqlQuery` already renders the same upstream `Promise<any>`. A caller that ignores it is unaffected.
+
+The real signatures forwarded to:
 
 ```ts
 // index.d.ts:60 — the installed web SDK's doc_create
@@ -389,7 +394,9 @@ export async function postToDocument(doc: NuriLike, opts: PostOptions): Promise<
 export async function share(doc: NuriLike, toUser: string): Promise<void>;
 export async function read(targetInbox: NuriLike): Promise<Deposit[]>;
 export async function readForDocument(doc: NuriLike): Promise<Deposit[]>;
-export const materialize = read;
+// `materialize` — a second published name for `read` — was REMOVED on 2026-08-14. It was
+// an alias and nothing else: no call site, and upstream has no such member, so it was a
+// symbol an application could learn and would then have to unlearn. Use `read`.
 export async function readSynced(targetInbox: NuriLike): Promise<Deposit[]>;
 export async function processInbox(targetInbox: NuriLike): Promise<Deposit[]>;
 export function watch(
@@ -412,7 +419,7 @@ Consequences per function:
 
 - `post` / `postToDocument` — the sender-side act exists in the model (the broker routes `InboxPost` natively, `engine/net/src/server_broker.rs`); its JS surface does not. **The future SDK's name and signature are unknown** — `docs/nextgraph-current-state.md:187` records that nothing is announced. `postToDocument`'s resolution step (find the document's inbox address) rides on a **deliberate divergence**: this lib PUBLISHES the address on the document (Header-branch emulation), whereas upstream an address is only ever TRANSMITTED (`ContactDetails` carries `ng:site_inbox`/`ng:protected_inbox`, `engine/verifier/src/inbox_processor.rs:778-830`; the address→repo association lives in `inboxes: PubKey → RepoId`, a table of the **verifier** — one per user, `verifier.rs:105`). *(Corrected 2026-08-10: this said the table was "session-local, rebuilt empty". It is initialized empty (`verifier.rs:520,2820`) and then repopulated at every load — `Verifier::load` → `add_repo_without_saving` → `add_repo_`, `verifier.rs:534-566,2871,2887` — with the inbox private key persisted per repo, `user_storage/repo.rs:61,171,207,362`. The property that matters is that it is **per verifier**, not that it is ephemeral.)* Documented in `docs/briefs/2026-08-03-document-inbox-addressing.md`.
 - `share` — a **gap upstream, not a disagreement**, verified at both ends: `ContactDetails.read_cap: Option<ReadCap>` exists (`engine/net/src/types.rs:4233`) but building a message with it is `unimplemented!()` (`types.rs:3786`), its only caller passes `with_readcap: false`, and the receiving arm never reads the field (`inbox_processor.rs:778-830`). `InboxMsgContent::Link` is a **unit variant carrying nothing** (`types.rs:4252`) — do not read it as the delivery channel. The recipient-side filing the lib emulates is real: `AddLink { read_cap }` on the User branch (`engine/repo/src/types.rs:1939-1948`). The consumer's *act* (share one document's cap to one inbox) is target-shaped; only the transport is emulated.
-- `read` / `materialize` / `readSynced` / `processInbox` / `watch` — **stand-ins for the recipient's own verifier processing**, which has no consumer-facing JS surface upstream and may never have this list-of-deposits shape. A consumer should treat "my inbox gets processed when I connect, and applied caps just appear in what I hold" as the durable contract (that is what `connectedUser` automates, § 13); code that leans on enumerating raw deposits as a mailbox UI is coding against emulation detail it may have to unlearn. The consumer-payload case (`Deposit.payload` as app data) maps to `InboxMsgContent` variants upstream (`types.rs:4249-4260`), of which only `ContactDetails` and `SocialQuery` are more than unit variants today — arbitrary app payloads through the inbox are an **ASSUMPTION**, constrained by the model only in that messages are sealed, per-recipient, and applied by the recipient.
+- `read` / `readSynced` / `processInbox` / `watch` — **stand-ins for the recipient's own verifier processing**, which has no consumer-facing JS surface upstream and may never have this list-of-deposits shape. A consumer should treat "my inbox gets processed when I connect, and applied caps just appear in what I hold" as the durable contract (that is what `connectedUser` automates, § 13); code that leans on enumerating raw deposits as a mailbox UI is coding against emulation detail it may have to unlearn. The consumer-payload case (`Deposit.payload` as app data) maps to `InboxMsgContent` variants upstream (`types.rs:4249-4260`), of which only `ContactDetails` and `SocialQuery` are more than unit variants today — arbitrary app payloads through the inbox are an **ASSUMPTION**, constrained by the model only in that messages are sealed, per-recipient, and applied by the recipient.
 - `readForDocument(doc)` — the owner's side of a document's inbox, named by the DOCUMENT. Same LEVEL-1 SHAPE ruling as `read`: it is the recipient's own processing, which has no consumer-facing JS surface upstream, and enumerating its deposits is emulation detail. It exists so an application never handles an inbox address.
 - `share(doc, toUser)` **refuses an unknown recipient** since 2026-08-10. It used to provision one: a mistyped name minted that name's stores and an inbox, and the cap landed where nobody looks. Upstream a deposit is sealed to an inbox pubkey that reached you through an inbound contact, so you cannot address a name you invented.
 - `watch`'s `_opts?: { intervalMs?: number }` is accepted and **ignored** (kept for signature compatibility with a removed polling watcher) — dead surface, see § 15.
@@ -531,7 +538,7 @@ interface VirtualUserRecord {
 }
 // RegistrySession is INTERNAL since 2026-08-12 (shape kept here for the ruling below).
 interface RegistrySession {
-  sessionId: string;
+  sessionId: string | number;   // relayed untouched — upstream's own type (§ 7)
   privateStoreId: string;
   protectedStoreId?: string;
   publicStoreId?: string;
@@ -661,7 +668,7 @@ Exported, but not SDK surface. Coding against these builds knowledge that migrat
 - ~~**The SDK entry is not as pure as its header claims.**~~ **FIXED 2026-08-03.** The header claimed the entry "exposes ONLY what `@ng-org/web` / `@ng-org/orm` expose" while also shipping `virtualUsers` and the whole `store-registry` module. Both are gone from it, and the header now states what the entry actually promises: *every symbol here has a target-SDK counterpart, verified or assumed, listed in this document*. It still exports `docs`, `readUnion`, `watchShape`, `subscribeDoc(s)`, the SPARQL helpers and the NURI guards — justified inventions, documented per subject above — so the promise is no longer "@ng-org surface only", which was never true, but "nothing here is machinery".
 - ~~**`share` is importable from both entries.**~~ **FIXED 2026-08-07** with the entry merge: there is one entry and one `share`, under `inbox`.
 - **One entry means the import line no longer says what disappears.** Until 2026-08-07 a second import path (`/polyfill`) WAS the deletion list. It is now the `POLYFILL-ERA` block in `src/index.ts`, this appendix's note above, and the per-subject rulings in this document. That is a documentation-carried signal where it used to be a mechanical one — the appendix is pinned by a test, the grouping is not.
-- **`inbox.read`/`materialize` as a mailbox** — enumerating raw deposits is emulation detail (§ 9); the durable contract is deposit-and-it-gets-applied. An app building UI on the deposit list should expect that surface to change shape entirely.
+- **`inbox.read` as a mailbox** — enumerating raw deposits is emulation detail (§ 9); the durable contract is deposit-and-it-gets-applied. An app building UI on the deposit list should expect that surface to change shape entirely.
 - **`watchShape`'s "planned `useShape` upgrade"** — stated in the module header with no provenance in this repo or the clone (§ 5). The load-state *distinction* is safe; the claim that NextGraph plans this exact hook shape is an assumption and must not be cited as an announced API.
 - **`UnionSubject` property bags** — polyfill read-model shape, not a target type; map them into app types at the boundary (which `watchShape`'s design already assumes).
 - **The sync-returning `subscribeDoc` unsubscribe** vs the target's promise-resolved one (§ 8) — a deliberate, documented ergonomic delta; an adapter is one line at migration, but it is a delta.
@@ -677,7 +684,7 @@ Exported, but not SDK surface. Coding against these builds knowledge that migrat
 ```text
 direct: BaseType, DeepSignalSet, DocChange, DocChangeType, EventuallyConfig, NG, NgLike, Nuri, NuriLike, PrincipalId, Schema, Scope, ShapeObservable, ShapeQuery, ShapeType, SharedWalletConfig, UnionSubject, Unsubscribe, UseShapeLike, configure, docChangeType, ensureIdentity, init, initNg, ng, readUnion, subscribeDoc, subscribeDocs, useShape, watchShape
 docs: docCreate, sparqlQuery, sparqlUpdate
-inbox: Deposit, PostOptions, materialize, post, postToDocument, processInbox, read, readForDocument, readSynced, share, watch
+inbox: Deposit, PostOptions, post, postToDocument, processInbox, read, readForDocument, readSynced, share, watch
 storeRegistry: createEntityDoc, listMyEntityDocs, openDocumentInbox, resolveScopeGraph, resolveWriteGraph
 ```
 
diff --git a/packages/polyfill/src/emulated-verifier/register-write.ts b/packages/polyfill/src/emulated-verifier/register-write.ts
index 73c3477..156d16d 100644
--- a/packages/polyfill/src/emulated-verifier/register-write.ts
+++ b/packages/polyfill/src/emulated-verifier/register-write.ts
@@ -32,7 +32,7 @@ import type { Nuri } from "../model/types";
  * nothing else. Never exported from the package.
  */
 export async function registerUpdate(
-  sessionId: string,
+  sessionId: string | number,
   query: string,
   anchor: Nuri,
   label = "registerUpdate",
@@ -66,7 +66,7 @@ export async function registerUpdate(
  * only caller, and reading is guarded separately (`inbox.read`).
  */
 export async function depositInto(
-  sessionId: string,
+  sessionId: string | number,
   query: string,
   targetInbox: Nuri,
   label = "deposit",
diff --git a/packages/polyfill/src/index.ts b/packages/polyfill/src/index.ts
index 50f6ae9..b44a580 100644
--- a/packages/polyfill/src/index.ts
+++ b/packages/polyfill/src/index.ts
@@ -139,7 +139,15 @@ export type { EventuallyConfig } from "./shared-wallet/bootstrap";
 export { ensureIdentity } from "./shared-wallet/access-gate";
 export type { SharedWalletConfig } from "./shared-wallet/access-gate";
 
+import type { NG } from "@ng-org/web";
+
 import { makeNg } from "./surface/ng-proxy";
 
-/** SDK-identical `ng` (wrapped). Drop-in replacement for `@ng-org/web`'s `ng`. */
-export const ng: Record<string, any> = makeNg();
+/**
+ * SDK-identical `ng` (wrapped). Drop-in replacement for `@ng-org/web`'s `ng`.
+ *
+ * Declared `NG` — upstream's own type for its `ng` (`index.d.ts:138`). It was published as
+ * `Record<string, any>` until 2026-08-14, which announced a different surface from the one
+ * it forwards to: an application got no completion and no check on any of the 88 members.
+ */
+export const ng: NG = makeNg();
diff --git a/packages/polyfill/src/shared-wallet/account-registry.ts b/packages/polyfill/src/shared-wallet/account-registry.ts
index 6fda803..6fa8e00 100644
--- a/packages/polyfill/src/shared-wallet/account-registry.ts
+++ b/packages/polyfill/src/shared-wallet/account-registry.ts
@@ -250,7 +250,8 @@ export function accountKey(id: string): string {
 
 /** Minimal session shape the registry needs — provided by the consumer. */
 export interface RegistrySession {
-  sessionId: string;
+  /** Relayed untouched to `ng` — upstream declares it `string | number` (`index.d.ts:266`). */
+  sessionId: string | number;
   /** The shared wallet's private store id — the pointer anchor. */
   privateStoreId: string;
   /** The shared wallet's protected store id (native store). Optional: only the
diff --git a/packages/polyfill/src/shared-wallet/physical.ts b/packages/polyfill/src/shared-wallet/physical.ts
index eec3b1b..2782f65 100644
--- a/packages/polyfill/src/shared-wallet/physical.ts
+++ b/packages/polyfill/src/shared-wallet/physical.ts
@@ -55,7 +55,7 @@ import type { Nuri } from "../model/types";
  * afterwards, which the caller decides by filing the cap among the caps that holder holds.
  */
 export async function physicalCreate(
-  sessionId: string,
+  sessionId: string | number,
   crdt = "Graph",
   cls = "data:graph",
   dest = "store",
@@ -81,7 +81,7 @@ export async function physicalCreate(
  * read a virtual user's content — that is `docs.sparqlQuery`, which is confined.
  */
 export async function physicalQuery(
-  sessionId: string,
+  sessionId: string | number,
   query: string,
   base: string | undefined,
   anchor: Nuri,
@@ -95,7 +95,7 @@ export async function physicalQuery(
 
 /** Write as the PHYSICAL user — the shim's own records. See {@link physicalQuery}. */
 export async function physicalUpdate(
-  sessionId: string,
+  sessionId: string | number,
   query: string,
   anchor: Nuri,
   label = "physicalUpdate",
diff --git a/packages/polyfill/src/shared-wallet/session.ts b/packages/polyfill/src/shared-wallet/session.ts
index 39f70fc..849341d 100644
--- a/packages/polyfill/src/shared-wallet/session.ts
+++ b/packages/polyfill/src/shared-wallet/session.ts
@@ -95,15 +95,15 @@ export function sessionIsComing(): boolean {
  *
  * ── The session id is RELAYED, never rebuilt — and that is load-bearing ────
  * Upstream declares it `string | number` (`Session`, `index.d.ts:266`) and the broker
- * returns a NUMBER; the whole chain below here types it `string` and hands it to `ng.*`,
+ * returns a NUMBER; the chain below here now types it the same way and hands it to `ng.*`,
  * whose binding takes it as-is. So this reads the field and passes it on untouched. It is
  * not a detail: normalizing it to a string was written here first, and the applicative e2e
  * refused every call in the batch with `Deserialization error of session_id JsValue("1")`
  * — the wasm side deserializes the id by its own type, and a stringified number is not it.
  *
- * The `string` in the declared shape is therefore inherited, not asserted: the inaccuracy
- * is the chain's and predates this module (every consumer's thunk declared it the same way
- * and relayed the same value). Widening it belongs to the chain, not to the capture.
+ * The chain used to narrow it to `string`, which made the value the SDK hands an application
+ * unpassable through this library. Widened to upstream's own declared type on 2026-08-14, at
+ * the capture and along every hop that relays it; the id is still only ever RELAYED.
  */
 export function captureSession(event: unknown): boolean {
   if (typeof event !== "object" || event === null) return false;
@@ -116,7 +116,7 @@ export function captureSession(event: unknown): boolean {
     protected_store_id: protectedStoreId,
     public_store_id: publicStoreId,
   } = session as {
-    session_id?: string;
+    session_id?: string | number;
     private_store_id?: string;
     protected_store_id?: string;
     public_store_id?: string;
diff --git a/packages/polyfill/src/surface/docs.ts b/packages/polyfill/src/surface/docs.ts
index 269f878..05d2aa5 100644
--- a/packages/polyfill/src/surface/docs.ts
+++ b/packages/polyfill/src/surface/docs.ts
@@ -44,8 +44,15 @@ function rowCount(result: unknown): number {
  * document in the (shared) private store: `docCreate(sid, "Graph", "data:graph",
  * "store")` (store_repo left undefined → private store).
  */
+// The session id is `string | number` because that is what upstream DECLARES for it
+// (`Session.session_id`, `sdk/js/web/src/index.ts:16` and the installed `index.d.ts:266`),
+// and the wasm side deserializes it as a `u64` (`sdk/js/lib-wasm/src/lib.rs:352-358`
+// `sparql_query`, `:452-457` `sparql_update`, `:1575` `doc_create`). It only ever TRAVELS
+// through this chain — never normalise it, and above all never stringify it: a JS string
+// fails that deserialization, observed live as
+// `Deserialization error of session_id JsValue("1")`.
 export async function docCreate(
-  sessionId: string,
+  sessionId: string | number,
   crdt: string,
   cls: string,
   dest: string,
@@ -82,13 +89,21 @@ export async function docCreate(
  *
  * Mirrors `ng.sparql_update(session_id, query, anchor?)`, where `anchor` is the
  * document NURI the update is scoped/base'd to (optional).
+ *
+ * Returns what the real method returns: upstream answers the COMMITS the update
+ * produced (`sdk/js/lib-wasm/src/lib.rs:481-483` serialises `AppResponseV0::Commits`;
+ * the installed `index.d.ts:297` types it `Promise<any>`). This function already
+ * relayed that value at runtime — only the declared type said `void`, which threw the
+ * answer away for every caller. Typed `unknown` rather than `any`, exactly as
+ * {@link sparqlQuery} already renders the same upstream `Promise<any>`: the value is
+ * the broker's to shape, and a caller that ignores it is unaffected.
  */
 export async function sparqlUpdate(
-  sessionId: string,
+  sessionId: string | number,
   query: string,
   anchorLike?: NuriLike,
   label = "sparqlUpdate",
-): Promise<void> {
+): Promise<unknown> {
   const { ng } = getConfig();
   const anchor = anchorLike === undefined ? undefined : toNuri(anchorLike, "docs.sparqlUpdate");
   // The boundary, in two questions that are NOT the same one.
@@ -117,7 +132,7 @@ export async function sparqlUpdate(
  * query base IRI (usually `undefined`); `anchor` is the document NURI to query.
  */
 export async function sparqlQuery(
-  sessionId: string,
+  sessionId: string | number,
   query: string,
   base?: string,
   anchorLike?: NuriLike,
diff --git a/packages/polyfill/src/surface/inbox.ts b/packages/polyfill/src/surface/inbox.ts
index 070613e..45a8c38 100644
--- a/packages/polyfill/src/surface/inbox.ts
+++ b/packages/polyfill/src/surface/inbox.ts
@@ -84,7 +84,7 @@ const P = {
 
 /** The inbox documents live in the shared wallet, so we reuse the registry's
  *  injected session provider for the sessionId. Disappears at migration. */
-async function sessionId(): Promise<string> {
+async function sessionId(): Promise<string | number> {
   return (await getStoreRegistryDeps().getSession()).sessionId;
 }
 
@@ -519,8 +519,10 @@ export async function read(targetInboxLike: NuriLike): Promise<Deposit[]> {
   return delivered;
 }
 
-/** Alias for {@link read} — the name that reads as "process the inbox now". */
-export const materialize = read;
+// `materialize` — a second published name for {@link read} — was REMOVED from the surface
+// on 2026-08-14. It was an alias and nothing more: no call site anywhere, and upstream has
+// no such member, so it was a symbol an application could learn and would have to unlearn.
+// `read` is the name; the word "materialize" survives only as prose in the docs.
 
 /**
  * COLD, BARRIER-GATED read of `targetInbox` — the reliable "process the inbox at
diff --git a/packages/polyfill/src/surface/ng-proxy.ts b/packages/polyfill/src/surface/ng-proxy.ts
index 1291412..79f0949 100644
--- a/packages/polyfill/src/surface/ng-proxy.ts
+++ b/packages/polyfill/src/surface/ng-proxy.ts
@@ -4,61 +4,79 @@
  * surface stays identical to `@ng-org/web`'s `ng`.
  */
 
+import type { NG } from "@ng-org/web";
+
 import { getConfig, getCaps, getCurrentUser } from "../shared-wallet/bootstrap";
 import type { Nuri } from "../model/types";
 
-export function makeNg(): Record<string, any> {
-  return new Proxy({} as Record<string, any>, {
-    get(_target, prop: string) {
+/**
+ * Typed `NG` — upstream's own type for `ng` (`NG = typeof NGModule`, 88 exported members,
+ * installed `index.d.ts:136-231`). The proxy adds no member and removes none, so this is
+ * the honest declaration; it used to be `Record<string, any>`, which silently dropped all
+ * 88 signatures and let any misspelt member typecheck.
+ *
+ * The empty object is only the Proxy's TARGET: every property is answered by the `get`
+ * trap below, never by the target, so there is nothing to put in it. Typing the target is
+ * how `new Proxy` carries a type to its result — not an escape hatch, and the surface it
+ * announces is checked against upstream's for every caller.
+ */
+export function makeNg(): NG {
+  return new Proxy({} as NG, {
+    get(_target, prop: string | symbol) {
       const { ng } = getConfig();
+      // The overrides below are keyed by NAME, so they are only consulted for a string
+      // property. A symbol (`Symbol.toStringTag`, `Symbol.asyncIterator`, …) skips them and
+      // falls to the same passthrough as everything else at the bottom — bound identically,
+      // so the proxy stays transparent for every kind of key.
+      if (typeof prop === "string") {
+        // session_start → open the SHARED wallet invisibly.
+        //
+        // `login` used to be listed here too. `@ng-org/web` exposes no such method —
+        // zero occurrences in the installed declarations and in `sdk/js/lib-wasm/src/lib.rs`
+        // — so the proxy FABRICATED a member: `ng.login` answered a function instead of
+        // `undefined`, and calling it threw. The one place this wrapper added to the SDK
+        // surface, against its own header. Removed 2026-08-03.
+        if (prop === "session_start") {
+          return (...args: any[]) => {
+            // TODO(polyfill): supply shared-wallet credentials so no wallet UI
+            // is shown. For now, passthrough.
+            return ng[prop]!(...args);
+          };
+        }
 
-      // session_start → open the SHARED wallet invisibly.
-      //
-      // `login` used to be listed here too. `@ng-org/web` exposes no such method —
-      // zero occurrences in the installed declarations and in `sdk/js/lib-wasm/src/lib.rs`
-      // — so the proxy FABRICATED a member: `ng.login` answered a function instead of
-      // `undefined`, and calling it threw. The one place this wrapper added to the SDK
-      // surface, against its own header. Removed 2026-08-03.
-      if (prop === "session_start") {
-        return (...args: any[]) => {
-          // TODO(polyfill): supply shared-wallet credentials so no wallet UI
-          // is shown. For now, passthrough.
-          return ng[prop]!(...args);
-        };
+        // sparql_update → write guard (emulated write-cap check).
+        // Mirrors the target broker/verifier: a write is refused unless the wallet
+        // holds the document's WRITE cap. Emulated per-document via CapRegistry.
+        // args = (session_id, query, anchor?) — `anchor` is the target doc NURI.
+        if (prop === "sparql_update") {
+          return (...args: any[]) => {
+            const anchor = args[2] as Nuri | undefined;
+            const caps = getCaps();
+            // Passthrough (no regression) unless a WRITE policy exists AND this
+            // specific document is governed by it. Ungoverned docs (mono-store
+            // default, no cap declared) flow through exactly as before.
+            if (
+              typeof anchor === "string" &&
+              caps.hasWritePolicy() &&
+              caps.governsWrite(anchor) &&
+              !caps.canWrite(anchor, getCurrentUser())
+            ) {
+              return Promise.reject(
+                new Error(
+                  `[ng-eventually] write denied: current user lacks the write cap for ${anchor}`,
+                ),
+              );
+            }
+            return ng.sparql_update!(...args);
+          };
+        }
+
+        // TODO(anticipated API): a sealed inbox deposit + capability operations — expose
+        // here with their anticipated signatures, emulated for now.
       }
 
-      // sparql_update → write guard (emulated write-cap check).
-      // Mirrors the target broker/verifier: a write is refused unless the wallet
-      // holds the document's WRITE cap. Emulated per-document via CapRegistry.
-      // args = (session_id, query, anchor?) — `anchor` is the target doc NURI.
-      if (prop === "sparql_update") {
-        return (...args: any[]) => {
-          const anchor = args[2] as Nuri | undefined;
-          const caps = getCaps();
-          // Passthrough (no regression) unless a WRITE policy exists AND this
-          // specific document is governed by it. Ungoverned docs (mono-store
-          // default, no cap declared) flow through exactly as before.
-          if (
-            typeof anchor === "string" &&
-            caps.hasWritePolicy() &&
-            caps.governsWrite(anchor) &&
-            !caps.canWrite(anchor, getCurrentUser())
-          ) {
-            return Promise.reject(
-              new Error(
-                `[ng-eventually] write denied: current user lacks the write cap for ${anchor}`,
-              ),
-            );
-          }
-          return ng.sparql_update!(...args);
-        };
-      }
-
-      // TODO(anticipated API): a sealed inbox deposit + capability operations — expose
-      // here with their anticipated signatures, emulated for now.
-
       // Everything else: passthrough to the real SDK, unchanged.
-      const real = ng[prop];
+      const real = Reflect.get(ng, prop);
       return typeof real === "function" ? real.bind(ng) : real;
     },
   });
diff --git a/packages/polyfill/src/surface/read-model.ts b/packages/polyfill/src/surface/read-model.ts
index ef837c7..0ef3a86 100644
--- a/packages/polyfill/src/surface/read-model.ts
+++ b/packages/polyfill/src/surface/read-model.ts
@@ -97,7 +97,7 @@ function bindings(
   return anyRes.results?.bindings ?? [];
 }
 
-async function sessionId(): Promise<string> {
+async function sessionId(): Promise<string | number> {
   return (await getStoreRegistryDeps().getSession()).sessionId;
 }
 
@@ -122,7 +122,7 @@ async function sessionId(): Promise<string> {
  * store repo by cap is a native broker fetch (`verifier.rs:1423` `OpenRepo` TODO).
  */
 async function readDoc(
-  sid: string,
+  sid: string | number,
   doc: Nuri,
 ): Promise<Array<Record<string, { value: string } | undefined>>> {
   try {
diff --git a/packages/polyfill/src/surface/subscribe.ts b/packages/polyfill/src/surface/subscribe.ts
index 2357b1a..1fd14b9 100644
--- a/packages/polyfill/src/surface/subscribe.ts
+++ b/packages/polyfill/src/surface/subscribe.ts
@@ -79,7 +79,7 @@ export function docChangeType(resp: DocChange): DocChangeType {
 /** An unsubscribe function — idempotent (calling it twice is a no-op). */
 export type Unsubscribe = () => void;
 
-async function sessionId(): Promise<string> {
+async function sessionId(): Promise<string | number> {
   return (await getStoreRegistryDeps().getSession()).sessionId;
 }
 
diff --git a/packages/polyfill/test/docs.test.ts b/packages/polyfill/test/docs.test.ts
index b9b7a67..81be203 100644
--- a/packages/polyfill/test/docs.test.ts
+++ b/packages/polyfill/test/docs.test.ts
@@ -29,10 +29,16 @@ import { configure } from "../src/index";
 import { setCurrentUser } from "../src/shared-wallet/bootstrap";
 import { resetCaps } from "../src/shared-wallet/bootstrap";
 
+// What a real `ng.sparql_update` answers: the COMMITS the update produced
+// (`sdk/js/lib-wasm/src/lib.rs:481-483` serialises `AppResponseV0::Commits`). The fake
+// used to answer `undefined` — a result the broker never returns — which is precisely
+// what let the surface declare `Promise<void>` unchallenged.
+const COMMITS = [{ id: "did:ng:c:commit-1" }, { id: "did:ng:c:commit-2" }];
+
 function fakeNg() {
   return {
     doc_create: mock(async (..._a: unknown[]) => "did:ng:o:new-doc"),
-    sparql_update: mock(async (..._a: unknown[]) => undefined),
+    sparql_update: mock(async (..._a: unknown[]) => COMMITS),
     sparql_query: mock(async (..._a: unknown[]) => ({ results: { bindings: [] } })),
     // A sentinel: makeNg(), if ever used, would `.bind` and call THIS through
     // the JS Proxy. We assert the primitives call the raw fns above directly.
@@ -83,6 +89,41 @@ test("sparqlQuery forwards (sessionId, query, base, anchor) and returns the raw
   ]);
 });
 
+// ── the session id: RELAYED, never converted ──────────────────────────────────
+// Upstream declares it `string | number` (`Session.session_id`, `index.d.ts:266`) and the
+// broker hands back a NUMBER, which the wasm binding deserializes as a `u64`. Stringifying
+// it fails that deserialization for real (`Deserialization error of session_id JsValue("1")`),
+// so what reaches the boundary must be the very value the caller passed — same `typeof`.
+test("a NUMERIC session id reaches ng untouched, still a number", async () => {
+  const ng = inject();
+  // Anchor the update and the read on the document just CREATED: creating it mints its
+  // cap, so the reach guard (process-wide once any cap exists) is satisfied the way a real
+  // application satisfies it — rather than by naming a document this user does not hold.
+  const created = await docCreate(1, "Graph", "data:graph", "store", undefined);
+  await sparqlUpdate(2, "INSERT DATA {}", created);
+  await sparqlQuery(3, "SELECT * {}", undefined, created);
+
+  const createdSid = ng.doc_create.mock.calls[0]![0];
+  expect(createdSid).toBe(1);
+  expect(typeof createdSid).toBe("number");
+
+  const updated = ng.sparql_update.mock.calls[0]![0];
+  expect(updated).toBe(2);
+  expect(typeof updated).toBe("number");
+
+  const queried = ng.sparql_query.mock.calls[0]![0];
+  expect(queried).toBe(3);
+  expect(typeof queried).toBe("number");
+});
+
+test("sparqlUpdate hands back what the boundary returned", async () => {
+  // The commits must arrive at the caller unchanged — the surface used to declare
+  // `Promise<void>` and throw this answer away.
+  inject();
+  const returned = await sparqlUpdate("sid-c", "INSERT DATA {}", "did:ng:o:a");
+  expect(returned).toBe(COMMITS);
+});
+
 test("the primitives do NOT route through the public ng proxy (makeNg)", async () => {
   // makeNg builds a JS Proxy over the injected ng. If a primitive went through
   // it, calls would land on the proxy's `get` trap, not on our raw mock fns.
diff --git a/packages/polyfill/test/inbox.test.ts b/packages/polyfill/test/inbox.test.ts
index b1b72ff..6a5db8a 100644
--- a/packages/polyfill/test/inbox.test.ts
+++ b/packages/polyfill/test/inbox.test.ts
@@ -1,5 +1,6 @@
 import { test, expect, mock, beforeEach, afterAll } from "bun:test";
-import { post, read, materialize, watch } from "../src/surface/inbox";
+import { post, read, watch } from "../src/surface/inbox";
+import * as polyfill from "../src/index";
 import { userInbox, resetRegistryCache } from "../src/shared-wallet/account-registry";
 import type { Deposit } from "../src/surface/inbox";
 import { configure } from "../src/index";
@@ -249,14 +250,23 @@ test("from: null makes an anonymous deposit even when a current user is set", as
   expect(deposits[0]!.from).toBeNull();
 });
 
-test("read returns deposits sorted by ts ascending and materialize is an alias", async () => {
+test("read returns deposits sorted by ts ascending", async () => {
   await post(TARGET, { from: null, payload: "second", ts: 300 });
   await post(TARGET, { from: null, payload: "first", ts: 100 });
   await post(TARGET, { from: null, payload: "third", ts: 500 });
-  const deposits = await materialize(TARGET);
+  const deposits = await read(TARGET);
   expect(deposits.map((d) => d.payload)).toEqual(["first", "second", "third"]);
 });
 
+test("the published inbox surface exposes `read` and no `materialize` alias", () => {
+  // `materialize` was a second published name for `read` — a symbol an application could
+  // learn and would have to unlearn, since upstream has no such member. This asserts the
+  // PUBLISHED entry (`src/index.ts`'s `inbox` namespace), which is what an app imports,
+  // not merely the module it re-exports.
+  expect(typeof polyfill.inbox.read).toBe("function");
+  expect("materialize" in polyfill.inbox).toBe(false);
+});
+
 test("read is scoped to one inbox — deposits in another inbox are not returned", async () => {
   // The OTHER inbox is obtained from the system, not invented. A made-up NURI would be
   // a target no deposit can legitimately reach (`inbox.post` refuses what is not an
diff --git a/packages/polyfill/test/ng-proxy.test.ts b/packages/polyfill/test/ng-proxy.test.ts
index eecd3b6..c54a3e6 100644
--- a/packages/polyfill/test/ng-proxy.test.ts
+++ b/packages/polyfill/test/ng-proxy.test.ts
@@ -83,6 +83,9 @@ test("write guard: passthrough when anchor is omitted (cannot scope the guard)",
   getCaps().grantWrite(DOC, "alice");
   setCurrentUser("bob");
   const proxy = makeNg();
-  await proxy.sparql_update("sid", "INSERT DATA {}"); // no anchor → passthrough
+  // Anchor explicitly `undefined` — upstream declares all three parameters (`index.d.ts:297`),
+  // and the guard reads `args[2]`, which is `undefined` whether the argument is omitted or
+  // passed as such. Same branch, same passthrough.
+  await proxy.sparql_update("sid", "INSERT DATA {}", undefined); // no anchor → passthrough
   expect(ng.sparql_update).toHaveBeenCalledTimes(1);
 });