ng-eventually/docs/simulation.md

How this library emulates mature NextGraph on one shared wallet

Everything in this file is emulation. None of the behaviours described here is a real NextGraph feature: each is a stopgap the lib fabricates on top of the current, immature NextGraph (the exact gaps it compensates for are in nextgraph-current-state.md). Every piece has a real target and goes away when NextGraph matures — the swap is lib-only, and the consumer application's code is unchanged. The per-behaviour recap table lives in the top-level README.md (What is emulated (and how it goes away)); the removal checklist is migration-guide.md. Read this file for how each emulation works; read those two for what is fake and what replaces it.

The consumer application writes against @ng-eventually/client as if NextGraph already shipped per-entity documents in public/protected/private stores, capabilities and inboxes. It hasn't (see nextgraph-current-state.md). This file is the lib's own engineering doctrine on how it fabricates that mature face on top of one single shared wallet / broker. Everything here is polyfill-era and disappears at migration (migration-guide.md).

The premise: one shared wallet, everything readable

Current NextGraph has no cross-wallet read (OpenRepo is a TODO at engine/verifier/src/verifier.rs:1423; a foreign NURI raises RepoNotFound; a session only holds its own 3 stores in self.repos). So "each user their own wallet" is blocked at the root — no data ever crosses the boundary between two wallets.

The lib's answer: everyone opens the same wallet. NextGraph sees a single identity, so everything is physically readable. "Multi-user" becomes an application fiction the lib maintains. On top of that one wallet the lib rebuilds, by emulation, the per-user stores + capabilities + inbox the consumer application codes against.

Physical user vs virtual user — never enumerate the physical one

Nomenclature (aligned on NextGraph, 2026-07-30). A wallet upstream is only a keyring; what owns three stores is a user (a site), and one wallet holds several of them (SensitiveWalletV0.sites, engine/wallet/src/types.rs:434,457). So this document says user, not wallet, for the thing an identity is — the two words meant the opposite of each other here until this was corrected.

Because the emulation runs on ONE shared wallet, distinguish two levels:

• The physical user — the single NextGraph user everybody's session opens. Its stores hold every account's documents plus the library's own internals (the pointer, the doc-shim, the inbox documents) as named graphs, accumulating without bound across sessions and runs. Listing or scanning "all documents" at this level is meaningless and O(size): it mixes every virtual user's data with library internals, and it is exactly what an anchorless sparql_query (GRAPH ?g { … }) does. The physical user is a substrate, not something to enumerate.

• A virtual user — the library's emulation of one identity: the documents the shim attributes to that account (its three store documents in shared-wallet/account-registry.ts). This is what "the user owns", and over it "list my documents" is meaningful and bounded.

Which API you use follows that line, and it is enforced (see shared-wallet/physical.ts): machinery operating on the index of virtual users — the store-root pointer, the doc-shim, the account records — goes through unguarded primitives that are never exported from the package. Everything touching a virtual user's own content goes through the guarded docs.*, even when the library is what calls it. One API is the app's; the other must never be.

Consequence for reads (see read-model.md): to list an identity's entities you enumerate the virtual user — that account's store document, bounded to its own documents — never the physical union. A bloated shared wallet then costs nothing, and nothing is enumerated across users at all: you read your own documents and the ones whose cap you were given.

At migration each virtual user becomes a real user with its own wallet; the physical/virtual distinction, the "never enumerate the physical one" rule, and shared-wallet/physical.ts all dissolve into native per-user reads.

Two axes, never conflate them (store ≠ document)

The single most load-bearing distinction. Two orthogonal axes the terminology historically fused:

• Axis A — which native store? A wallet has 3: private_store_id, protected_store_id, public_store_id. Historic origin of "mono-store / multi-store" (use 1 store vs the 3).
• Axis B — how many documents in a store? A store contains documents; the document (= repo = @graph) is the sharing + rights boundary. The ReadCap — hence isolation — is per-document.

docCreate(sessionId, "Graph", "data:graph", "store", undefined) targets the shared wallet's private store. The trailing store arg left undefined targets the private store (this is what shared-wallet/account-registry.ts's createDoc() does). So every document the shim creates physically lives in one store (private), and the public|protected|private scope is a logical label tracked in RDF by the shim — not a NextGraph store. Therefore what a consumer application's "multi-store" flag switches on is really multi-document with logical scope labels, never multi-store. Do not read Scope (types.ts) as a physical store — it is the logical label the registry attaches.

Why undefined and not a real store? Because doc_create cannot target a non-private native store today: StoreRepo is not JS-constructible (verified — see the parked getNativeStore note in migration-guide.md). The private store is reachable because it opens without RepoNotFound.

The shared-wallet shim (shared-wallet/account-registry.ts)

Emulates the target infrastructure — where each user owns their own public/protected/private stores — on top of one shared wallet.

• One document per (account × scope) inside the shared wallet, created via the docs.docCreate primitive. The scope (public|protected|private) is a logical attribute tracked here, not a physical store.
• The sharedWalletShim is the mapping account → its 3 scope-document NURIs. It is persisted as RDF, but not directly in the store-root graph — it lives in a subscribable doc-shim reached through a write-once pointer in the store-root, an indirection forced by a NextGraph fact: "findable-without-lookup" (store-root) and "subscribable / cold-read-authoritative" (did:ng:o: repo with a first-State barrier) are DISJOINT. The pointer (findable) names the doc-shim (authoritative); resolution reads the pointer from the store-root, opens the doc-shim through its barrier, and reads the account authoritatively — so a fresh reconnecting session never mistakes sync-lag for "account absent" (which would provision a FORK). Full rationale — including why the old account-level retry (provisionRetry) is removed (pre-indirection store-root records are NOT recovered; such wallets are dev data and simply get a fresh doc-shim) — is in nextgraph-current-state.md §§ Findable vs subscribable / The pointer → doc-shim indirection. This map is the account→document trust root, which is why every untrusted value that reaches its SPARQL is escaped (see SPARQL hardening below). It makes identity resolution cross-device: another device opening the same wallet reads the same pointer → the same doc-shim → the same accounts.
• Per-entity documents + per-scope index. createEntityDoc(id, scope) makes a dedicated document for one entity (mirrors the target, where each entity is its own document/repo with a future inbox) and appends its NURI to the account's scope index document — the index doc plays the role of the future store-container (it lists the entity-document NURIs "in" that scope). listMyEntityDocs(id, scope) reads back ONE user's documents — bounded to that user, and the only listing there is: the cross-account fan-out (listEntityDocs / resolveReadGraphs / allAccounts / loadShim) was removed on 2026-07-30, being cross-user enumeration by construction. The real read path is readModel.readUnion(docs), which reads the by-need doc set with one per-doc anchored sparql_query, never an anchorless union-scan of the physical wallet (see read-model.md). The consumer application resolves the by-need doc set from the current wallet's own scope index and listMyEntityDocs(id, scope) (its own account, bounded — no cross-account fan-out).
• Generic by construction. The registry knows only the three native scopes, zero application entity kind. The consumer application maps its entities to a scope and injects the session + identity-id normalization via configureStoreRegistry({ getSession, normalizeId }) (polyfill.ts).

The store≠document two axes materialize here directly: the registry moves along axis B (more documents = more isolation), never axis A (it always writes into the one private store via docCreate(..., undefined)).

A virtual user's structure — the three emulated stores

A virtual user = one account in the shim, keyed by its virtual-wallet id (the technical identifier the consumer application sets when the physical user is opened; it identifies which virtual user, and is an id rather than a human-friendly handle). Its structure mirrors the target "1 user = 1 wallet with 3 native stores":

Virtual user (id)
├── public store    = docPublic  index → [ entity doc NURI, entity doc NURI, … ]
├── protected store = docProtected index → [ record doc NURI, record doc NURI, … ]
└── private store   = docPrivate index → [ record doc NURI, … ]

So the 3 native stores (public/protected/private) are present, but emulated: each "store" is an index document (AccountRecord.{docPublic,docProtected,docPrivate}) that lists the NURIs of the per-entity documents in that scope. It is not a physical native store.

Everything is physical in one place: the 3 index documents, every per-entity document, and the shim anchor itself all live in the shared physical user's private store (docCreate(..., undefined)). The 3-store structure is the per-account logical layer the lib maintains on top.

Physical user (shared, one) → private_store (physical) holds everything:
   • the shim anchor:  virtual-wallet-id → { docPublic, docProtected, docPrivate }
   • every account's 3 scope-index docs + all per-entity docs + inboxes

At migration each virtual user's 3 index documents become the user's 3 real native stores, the entity documents move into them physically, and the virtual/physical distinction dissolves (see migration-guide.md).

SDK-shaped scope resolvers — the consumer application holds no store-id

The consumer application must never construct a did:ng:${store_id} NURI itself: physical placement is the lib's job (the whole point of the SDK boundary). Two resolvers turn a logical scope into an opaque graph NURI without exposing any store-id:

• resolveScopeGraph(scope) — the graph where the current session writes entities of scope, and whose repo useShape subscribes to read them back. Use the returned value as BOTH the read scope (useShape(shape, nuri)) and the @graph write target. Placement lives HERE (Axis A): private → the private native store; public + protected → the protected native store, because doc_create/ORM cannot target a non-private/protected native store today (SDK blocker, migration-guide.md). At migration each scope resolves to the user's real per-scope store — the change is in this function, and the consumer application is unchanged.
• walletInbox(id) / openDocumentInbox(doc) — an inbox BELONGS to someone. The first is a user's own inbox (where Links arrive), the second a DEDICATED inbox for one of its documents, opened on demand by its owner only (ownership read from the Store branches — a received cap is not ownership, and a recipient must not be able to redirect the owner's deposits to itself). Both are dedicated documents (real repo NURIs from docCreate), never the private-store root: routing deposits into the shim graph would bloat the account→document trust root without bound. myInboxes() enumerates both levels — what emulated-verifier/connect.ts drains at connection — and isOwnInbox answers from the same record. (The former resolveInboxAnchor, a single inbox COMMON to every user, was removed on 2026-07-30: nothing may be common but the mechanisms that make the virtual users work.)
• documentInboxAddress(doc) — the DEPOSIT side, and the one a third party uses. Reading an inbox and finding where to deposit into it are opposite acts with opposite audiences, and conflating them is what made per-document inboxes unusable at first: resolution answered "which inbox do I know for this document", so a depositor got one of their own and their deposit vanished silently (briefs/2026-08-03-document-inbox-addressing.md). A document that has an inbox carries its address on its emulated Header branch — a reserved subject inside the document, so any holder of the document reads it, and read-model filters the whole urn:ng-eventually: namespace out of consumer data (src/emulated-verifier/machinery.ts). This mirrors upstream's split: a depositor seals with the inbox PUBLIC key and needs nothing else, only the owner holds the private half. One inbox belongs to one document — never several documents behind one inbox, a relation upstream cannot express (the verifier routes by inboxes: PubKey → RepoId and unseals with that repo's key, engine/verifier/src/verifier.rs:1677,1928), which is also why a deposit carries no target document: the address identifies it. A fresh document therefore has NO inbox and documentInboxAddress returns undefined — its owner opens one when the document is meant to receive, which is what keeps the cost proportional. At migration the address becomes the repo's native inbox pubkey and the resolution moves; the consumer-facing act is unchanged.
• inbox.postToDocument(doc, { payload }) — the one call an app makes to reach a document's owner: it names the DOCUMENT, never an inbox. Throws when the document has no inbox, rather than returning quietly: a deposit that vanishes without an error is the exact bug this path shipped with.

Both resolve the native store ids from the injected session (RegistrySession.protectedStoreId / publicStoreId, alongside the existing privateStoreId anchor). The consumer application hands the whole session to the lib at the one injection point (configureStoreRegistry({ getSession })) — that is wiring, not placement logic; everything else in the consumer application speaks only in scopes. If the session omits protectedStoreId, the non-private scopes fall back to the private store rather than emit a broken NURI.

RepoNotFound and the orm_start_graph scope rule

A hard constraint inherited from the SDK: to read and write entities through the ORM, the store's repo must be explicitly opened in the verifier's self.repos HashMap. orm_start_graph with a store's NURI opens that repo; without it, orm_frontend_update fails with RepoNotFound.

• Scope for useShape: the store NURI, e.g. did:ng:${privateStoreId} (or, in the consumer application, a per-user store once that migration happens).
• @graph (write target): the same store NURI.
• Never use did:ng:i as a scope: it subscribes to the user's whole site via a special code path (NuriTargetV0::UserSite) that does not open individual repos, breaking every write with RepoNotFound.

Both the private and the protected native stores were verified to open the same way for ORM+SPARQL (round-trip probe, no RepoNotFound). The original arbitration is preserved in decisions/private-store-nuri-scope.md.

The @ng-org double-proxy DataCloneError constraint

A validated hard constraint, not a style choice: docs.ts calls the real injected ng (getConfig().ng) directly, never the public ng proxy (makeNg in surface/ng-proxy.ts).

@ng-org/web's ng is already an iframe-RPC proxy (postMessage marshaling, see nextgraph-current-state.md § integration). Wrapping it in the lib's own JS Proxy (double proxy) breaks doc_create's postMessage marshaling with DataCloneError: function ... could not be cloned. Reaching the real ng held in the config avoids the double-proxy. This was verified: routing the shim's doc_create/SPARQL through the public proxy turned 4 multistore scenarios red, so it was reverted. The integration boundary is:

• Through the lib's public proxy (validated): useShape (ORM + ReadCap filter), init/initNg, login.
• Through the real injected ng (docs.ts primitives): doc_create + all shim/inbox SPARQL.

docs.ts therefore imports no @ng-org package and must not import from ./ng-proxy.

Emulated ReadCap — per document (emulated-verifier/caps.ts + emulated-verifier/read-filter.ts)

In the target the broker only delivers documents the wallet holds a ReadCap for, so useShape already returns an authorized subset. Here (single shared wallet, everything readable) the lib reproduces that with a read-filtered view:

• CapRegistry (emulated-verifier/caps.ts) models a ReadCap as what it is: the document's key. The access unit is the document = repo NURI (an item's @graph), never the item — because in nextgraph-rs a store is just a container repo and holding its cap does not grant the repos it references (no store-level read inheritance; verified). The registry records, per identity, the caps it holds — Map<Nuri, ReadCap> — and answers exactly one question: capFor(nuri), do I hold this document's cap? There is deliberately no "may principal P read document D": that is an ACL question, and the real model cannot answer it either.
• nuri.ts carries the cap-less / cap-bearing distinction, which upstream is one object (NuriV0 { target, access }) discriminated by the :r:{cap} segment. Nuri names, ReadCap names and reads. Both are plain strings — the real SDK takes nuri: String and enforces at runtime through cryptography, so a branded type would be a concept NextGraph does not have. The stand-in key value is the constant OK (see the module header): the only question the emulation answers is do I hold this cap or not, so the value says exactly that and pretends nothing more. P1b, not P1a, is the batch that turns the shape into a protection.
• emulated-verifier/read-filter.ts — makeReadFilteredView wraps the reactive set in a Proxy: iteration / size / forEach keep only items whose @graph the current holder holds; everything else (add, delete, has, getById…) forwards to the target, preserving writes and reactivity. An item with no @graph is kept (it names no document, so there is no cap to hold). filterReadable is the pure variant. Note the absence of a user parameter — that absence is the model.
• useShape (surface/use-shape.ts) applies the view only once a cap exists at all (caps.isEnforcing()) — before that it passes the real set through unchanged (no regression for a consumer that never touches caps). Once ANY cap is issued the regime is possession for every holder, including one who holds nothing: that is the isolation.

In a mono-store layout (every item in one repo) this is all-or-nothing on that document — exactly the native behaviour, and why fine-grained isolation requires one document per entity (axis B).

Where caps come from — stored, never derived

doc_create returns a cap-less NURI, so "no function ever goes from a bare reference to a cap" cannot be the whole rule — it would lock a document's own creator out of it. The real mechanism: creating a document commits AddRepo { read_cap } to the store's Store branch, separately from the ldp:contains listing on its Main branch. That is where an owner finds the caps of what it created; a cap RECEIVED for someone else's document goes elsewhere, on the User branch (AddLink). The wallet itself holds one key per user — the private store's read cap — from which the rest is reached. Hence the invariant:

You do not derive a cap from a bare reference. You look it up in what you hold — or you were given it.

Three ways a cap arrives, and there are no others:

• Creation. createEntityDoc(id, scope) writes the cap on the store's emulated Store branch (shim:readCap) and the creator holds it. The consumer declares nothing, and the cap is minted exactly ONCE — the stored value is the held value, which is what keeps this correct when P1b makes the key real.
• Re-listing. listMyEntityDocs(id, scope) READS those records back. It does not recompute anything: that is the whole reason for storing them, and it is what lets a fresh session read its own documents again with nothing re-declared — the durability the old in-memory ACL faked and lost every reload.
• Delivery. shareCap(cap, toInbox) deposits one document's cap into one recipient's inbox; inbox.read applies it inline, exactly as the recipient's own verifier applies queued messages upstream. Receiving needs no operation — a consumer already watching its inbox gets them, and the resulting change re-triggers the reads that were empty for want of that cap.

The caps a holder holds are not the sharing mechanism. Handing over a store cap would give away everything the store contains, present and future. The unit of sharing is the document; the Store branch is a private index.

Switching identity switches records — it never wipes one. If it wiped, durability would be a lie and per-session re-declaration would come back under another name.

Sharing, publication, and the recipient

• setCurrentUser(id) (polyfill.ts) — the SDK's "current identity" call. It selects whose caps are consulted, lazily, so the delivered subset always reflects the identity in effect at read time.
• shareCap(cap, toInbox) — the one sharing act the lib exposes. Recipients are addressed as inboxes, which inbox.post(targetInbox) already does here; there is no PrincipalId in this surface, because that notion exists nowhere upstream. Reaching several recipients means calling it once per inbox, which is what the real model does too (each delivery is sealed to one recipient).
• getCaps().publishRepoLink(doc) — upstream RepoLinkV0: a shareable link whoever receives it can open. Put the link in what you make discoverable, not the bare NURI, or no reader can open it. Publication is not recursive: a public document may reference private ones, and the reference grants nothing on what it references — which is what lets a public object point at a private identity without disclosing it.

Upstream, directed delivery is a gap, not a disagreement: ContactDetails.read_cap exists, but the message construction is unimplemented!(), its only caller passes "without read_cap", and the receiver discards the cap. The shape is right; the implementation is absent, so this lib emulates it meanwhile.

Key rotation needs nothing on this surface. A rotated key is re-sent to the inbox of whoever keeps access, and that inbox is processed automatically at the next connection — so access is not lost, it is deferred, consistent with local-first. Same channel as the initial delivery, so there is no subscription obligation to expose and no special case to write. Revocation stays what it is: stop re-delivering, non-retroactive.

The relationship concept — who is "connected" to whom, and therefore whose documents to share — is owned by the consumer application, not the lib. A connection or friendship is not a NextGraph primitive; the only platform-mappable primitive is the per-document cap delivery above.

The result is the target's discrimination reproduced end-to-end: you read the documents whose caps you hold, and nothing else. Proven in test/isolation-active.test.ts (a document nobody shared is unreadable; a share to one inbox reveals it there and only there; a bare reference reads nothing while the repo link opens the published document; a returning identity keeps its caps) and in test/cross-user-access.test.ts, the acceptance test below.

This discrimination is only observable because each entity is its own document (the consumer application creates per-entity docs via createEntityDoc) — in a mono-store layout the per-document ReadCap is all-or-nothing.

The acceptance test — no cryptography required

Alice owns a protected document holding a secret and a public one that carries a reference to it. Bob, holding the public document's link, reads it, finds the reference, and can NAME the protected document while reading nothing of it — publication is not recursive. Charlie, holding the same link plus the protected document's cap (delivered to his inbox), reads through the very same reference. The only difference between them is each of them holds; nobody was named to any registry. And dynamically: the cap lands in Bob's inbox, his client processes it, and the read that was empty yields the content — the held-caps signal re-running it.

That is what real NextGraph does, and it holds without a line of encryption — which is what makes the P1a (shape) / P1b (enforcement) split honest rather than cosmetic. Proven in test/cross-user-access.test.ts.

After P1a the shape is right and the isolation is still fake. The stand-in key is a constant, and several read paths (docs.sparqlQuery/sparqlUpdate, the whole inbox, store-registry, subscribe, open-repo) consult no cap at all — worse, any wallet can reach any document. That is the subject of briefs/2026-07-30-virtual-wallet-boundary.md. Nothing may be claimed "anonymous" or "private" until it lands.

Write-guard coverage (honest scope)

The emulated write guard (surface/ng-proxy.ts, sparql_update override) enforces the per-document write cap on the public ng proxy only. In practice the consumer application's write paths (docs.sparqlUpdate, ORM ngSet) call the real injected ng directly — never the public proxy — for the validated DataCloneError reason above. So the guard is best-effort: it fires for any write routed through the public proxy, but the consumer application's real write paths bypass it and are not guarded today. This is a deliberate, recorded limitation of the emulation (the write guard becomes effective only when the broker/verifier enforces caps natively at migration); the read side is what makes isolation observably active.

The per-document ReadCap is the isolation path (item-level filter retired)

Isolation is enforced by the per-document ReadCap (emulated-verifier/caps.ts + emulated-verifier/read-filter.ts) alone: the access unit is the document (@graph = repo), and the only acts are possession-shaped (createEntityDoc files a cap, shareCap delivers one, publishRepoLink emits an openable link). Because the consumer application writes one document per entity, the per-document cap discriminates at entity granularity — the target's behaviour.

The old item-level application-visibility filter (the since-deleted isolation.ts applyIsolation, a Set-of-records filter keyed on owner+scope) is retired from the consumer path: the application carries no access logic — it declares its identity and shares caps, and trusts the SDK. Its matrix functions are dead scaffolding kept for reference and removed at migration. There is no longer a second, coexisting app-layer filter to reconcile — the single axis is the per-document cap, exactly as in the target.

Emulated inbox (inbox.ts)

Current NextGraph does not expose the inbox to the JS SDK (verifier has no InboxPost arm; no wasm sealing helper — see nextgraph-current-state.md § Inbox). Rather than fork the broker (fork-inbox-fallback.md), the lib emulates the inbox on the shared wallet:

• Target vs polyfill. In the target, post seals a reference into the owner's native inbox — through a JS call that does not exist and is not announced — and the recipient's own verifier unseals each queued message and applies it inline when it processes its inbox — there is no separate curator or materialization process. Here, everything is readable, so the lib emulates the read side in-lib.
• post(targetInbox, opts) appends a deposit { from, payload, ts } as RDF into the inbox document (in the shared wallet) via docs.sparqlUpdate. Each deposit is a unique RDF subject, so concurrent deposits don't collide. from is bound to the current identity (getCurrentUser) — it is authenticated, not caller-supplied: omit it to stamp the current user, pass null to deposit anonymously, and a from naming another principal is rejected as a spoof. This reproduces the protocol's "identified if known, anonymous otherwise" and the target's guarantee that a client cannot forge another's sender identity (in the target the broker seals from from the wallet's own key; here the check closes the spoof the shared wallet would otherwise allow). The emulation stores from = null as absence of a triple, so it does not provide the target's crypto anonymity (from = None sealed), which only a native inbox would. Proven in test/inbox.test.ts case (c).
• read / materialize (alias) emulate the recipient-side read: they read the deposits back via docs.sparqlQuery, JSON-parse each payload, sort by ts.
• watch(targetInbox, onDeposits, { intervalMs }) is the emulated watcher: it polls read and fires when the deposit count changes (the polyfill has no reactive inbox subscription). Fires once immediately; returns an unsubscribe.

An inbox BELONGS to a virtual user (2026-07-30)

storeRegistry.walletInbox(id) resolves — creating on first sight — the inbox document of one virtual user, recorded in the doc-shim under shim:docInbox and read by its own query (so an account written before this existed still resolves). The asymmetry that matters:

• Depositing into anyone's inbox is open. It is the ONLY way a link crosses from one wallet to another, and since you cannot discover, it is the bootstrap of the whole reachability graph. A deposit grants the depositor nothing in return — upstream it is an anonymous sealed box.
• Reading an inbox is confined to its owner (isOwnInbox, enforced in read / readSynced, hence in watch). Since P1a routes ReadCaps through deposits, an unguarded read let anyone who knew an inbox NURI collect the caps addressed to its owner — defeating directed sharing. Anonymous owns no inbox and reads none.

At migration this guard disappears into cryptography: an inbox is sealed to its owner's key.

The module knows no domain — the consumer application supplies the inbox document NURI and interprets payload. At migration post becomes the native sealed deposit — whose JS name and signature are not known, since none is exposed or announced — and the read side is served by the recipient's own verifier unsealing queued messages inline. The inbox + watcher is the one deposit/read mechanism a consumer reuses for its own purposes — a registration/deposit, a cap delivery (shareCap), a link handed to someone — same post API, same watcher.

The virtual user boundary (emulated-verifier/reach.ts + shared-wallet/physical.ts)

Every access function is confined to the user currently connected: no cross-user access, so the consumer is coded against a reach that will actually exist. Two rules, one criterion — possession — implemented in two places, deliberately redundant so a lapse in either is caught by the other:

• Rule 1, authorization (assertMayReach, at the passage points docs.sparqlQuery / sparqlUpdate / subscribeDoc): nothing reaches ng unless the connected user possesses that document's cap. It fires on a request that should never have been made, and makes it fail loudly rather than succeed quietly.
• Rule 2, do not even attempt (mustNotAttempt, at the callers — readUnion filters before opening or reading, ensureRepoOpen returns): a reader holding no cap does not issue the operation at all. Upstream you cannot even address a repo you have no cap for, so asking is not "a read that will be refused" — it is a read with no meaning.

Possession decides, never the shape of the reference in hand. A caller legitimately holds a bare NURI while possessing its cap elsewhere — references travel bare through content and stores, the cap sits in what the user holds.

The exception is depositing into another user's inbox (docs.depositInto): a named primitive rather than a flag, because it is a different act — you hold no cap, you cannot read back, and you get nothing in return. It is the only channel by which a link crosses between users, hence the bootstrap of the whole reachability graph.

The machinery lives in shared-wallet/physical.ts (see Physical user vs virtual user above): unguarded primitives, never exported from the package, used only for the index of virtual users. Separating the FUNCTIONS is what replaced an earlier exemption list — the machinery does not get waved through the guard, it calls something the guard never saw.

Connecting a user (emulated-verifier/connect.ts)

Processing inboxes is the library's job, not the app's: a consumer must never have to remember to drain a queue for documents shared with it to become readable — forgetting would look like "the share did not work" rather than "nobody consumed the queue". So setCurrentUser fires connectedUser(), which does two things in order:

1. Restore — read back the caps this user already applied (readLinks, the emulated AddLink records on its User branch) into what it holds. Durable state, one read, no inbox involved.
2. Drain — process every inbox it may read (myInboxes: its own, plus one per document it opened an inbox on), filing any new Link durably.

Restore-first is what lets a reconnecting user read its shared documents immediately instead of waiting on a queue round-trip.

Fire-and-forget, deliberately. The setter is synchronous and every consumer calls it from synchronous code; making it async would push the wait back onto the app, which is the obligation this removes. The work announces itself through CapRegistry.onChange — which watchShape already listens to — so a view that was empty for want of a cap re-reads when the cap lands. connectedUser() is exported for a caller that needs to await it (tests, a deterministic startup).

It does not provision. Connecting an identity that does not exist creates nothing (resolveAccount, not ensureAccount): otherwise connecting would mint a user's stores and their caps as a background side effect, arming the whole emulation at a moment nothing controls.

Cost worth knowing: setCurrentUser therefore has observable asynchronous effects — it reads, and it logs. Tests asserting on log output must await connectedUser() first.

Emulated discovery index + special account — REMOVED 2026-07-30

There is no discovery in NextGraph. You cannot discover; you can only follow links (see readcap-and-nuri-model.md §4ter-bis). Publishing is two acts — place the data in your public store, and circulate its link (into an inbox, or into a document the reader already holds) — and it is seen only by those who received the link.

discovery.ts (a global index owned by a reserved @index account, submitToIndex / readIndex / watchIndex), its tests, and watchShape's public-scope fold were removed. The module failed on two independent counts: it emulated a capability the target will never have — teaching consumers a model that does not exist — and it was data common to several wallets, where nothing may be common but the indexing mechanisms that make the virtual users work.

The ADR that specified it (decisions/discovery-model.md) is marked superseded, and keeps the part that survives: the discovery → synchronization → query frame still holds, with stage 1 re-read as "a link reached you" rather than "you consulted an index". Which makes the inbox the bootstrap of the whole reachability graph — see briefs/2026-07-30-virtual-wallet-boundary.md.

Emulated write guard (surface/ng-proxy.ts)

The public ng proxy overrides sparql_update to enforce an emulated write cap: a write is refused unless the current user holds the target document's write cap. It passes through (no regression) unless a write policy exists and that specific document (the anchor arg) is governed by it — ungoverned docs (the mono-store default, no cap declared) flow through unchanged. This mirrors the target broker/verifier, which refuses a write without the document's write cap.

Identity store (shared-wallet/accounts.ts)

The real NextGraph login (redirect to the broker, opening the single shared wallet) is perceived as a technical access barrier (see the login flow in decisions/shared-wallet-login-flow.md). This layer is not a login: it is an IdentityStore that holds the current identity id the consumer application relays to it:

• The identity id is set at wallet-import time by the consumer application and relayed to the lib via its current-identity call. It is persisted in localStorage so the id survives reloads and lands on the same account when the shared wallet re-opens. In practice the id is often a human-friendly handle the consumer application chose, but the lib's surface speaks only of an id.
• set(id) / clear() / get() only read/write the id in storage. They never call NextGraph (no session_stop / wallet_close) — the shared wallet stays open underneath. The real logout lives elsewhere (hidden in the consumer application's settings/debug), because it forces a new redirect.
• Framework-agnostic: no React, no DOM beyond an optional injected AccountStorage (a window.localStorage, a test fake, or null for SSR). The React Context/Provider stays in the consumer application. normalizeId (case-insensitive, optional leading @ stripped, trimmed) is the pure normalizer, reusable as the shim key normalizer.

SPARQL injection hardening (sparql.ts)

Every module that builds SPARQL by interpolation (inbox, store-registry) routes untrusted values through sparql.ts first, because a " closes a literal and a > closes an IRI, letting an injected value wreck the shim graph (the account → document trust root):

• escapeLiteral — for LITERAL position ("..."): escapes backslash, double-quote, C0 whitespace. Lossless (literals legitimately carry arbitrary text — JSON payloads, display names).
• escapeIri — for untrusted values embedded into an IRI (<PREFIX:${…}>, e.g. an identity id minted into an account-subject IRI): percent-encodes every IRI-hostile character so any id (spaces, unicode, punctuation) stays usable while breakout is impossible.
• assertNuri — for trusted-shaped NURIs coming back from ng (did:ng:...): validates and throws on IRI-breaking chars rather than emitting a malformed/injected query.

These are re-exported from @ng-eventually/client so the consumer application reuses the same escaping when it builds SPARQL.