diff --git a/docs/simulation.md b/docs/simulation.md
index 3e6c287..0ab2e96 100644
--- a/docs/simulation.md
+++ b/docs/simulation.md
@@ -194,19 +194,33 @@ calls; the consumer never touches the registry internals:
   consumer creates it: `public` → world-readable; `protected`/`private` → owner
   reads, owner holds the write cap. `open` now also **remembers** `(scope, owner)`
   per document so a later connection-driven grant can find the protected ones.
-- **`declareConnections(connections)` (`polyfill.ts`)** — the SDK-shaped
-  **protected sharing act**. The consumer hands its social graph (a `Connections`:
-  who-is-connected-to-whom) and the SDK issues, for every **protected** document,
-  that document's read cap to the owner's direct connections
-  (`CapRegistry.grantReadToConnections`). Public docs stay world-readable; private
-  docs stay owner-only. Re-callable whenever the graph changes; additive and
-  idempotent. The consumer passes only principals — no document NURI, no store id.
+- **`declareConnections(peers, as?)` (`polyfill.ts`)** — the SDK-shaped
+  **protected sharing act**, now **AUTHENTICATED / BILATERAL** (`connections.ts`).
+  Each call declares the CURRENT identity's OWN peers (`as` defaults to
+  `getCurrentUser()`); the lib records that as a **directed assertion authored by
+  the current identity** — a session can only ever assert its own side. A protected
+  read cap is issued between two principals only when **both have asserted the
+  other** (a materialized two-sided link, `ConnectionRegistry.neighbors` →
+  `CapRegistry.grantReadToConnections`). Public docs stay world-readable; private
+  docs stay owner-only. Re-callable; additive + idempotent. The consumer passes
+  only principals — no document NURI, no store id.
+
+  **Why bilateral (adversarial finding).** If a single directed assertion granted
+  access, any reader could read any owner's protected documents by unilaterally
+  self-declaring a connection. The two-sided requirement is the emulation of the
+  target's mutual capability exchange: only a reciprocated link grants the cap. A
+  unilateral / self-declared connection grants **nothing** (proven in
+  `test/connections.test.ts` and `test/isolation-active.test.ts` case (b)).
 
 The result is the target's discrimination reproduced end-to-end: **private** →
-owner; **protected** → owner + connections; **public** → all. Proven in
-`test/isolation-active.test.ts` (an unconnected principal is denied a protected
-document, granted it after `declareConnections`, and reads the public document
-throughout).
+owner; **protected** → owner + BILATERAL connections; **public** → all. Proven in
+`test/isolation-active.test.ts`: (a) an unconnected principal is denied a protected
+document, granted it after a two-sided `declareConnections`, and reads the public
+document throughout; (b) a unilateral/self-declared connection is denied.
+
+This discrimination is only observable because each entity is **its own document**
+(the consumer creates per-entity docs via `createEntityDoc` and `open`s each) — in
+a mono-store layout the per-document ReadCap is all-or-nothing.
 
 ### Write-guard coverage (honest scope)
 
@@ -220,25 +234,24 @@ through the public proxy, but the consumer's real write paths bypass it and are
 (the write guard becomes effective only when the broker/verifier enforces caps
 natively at migration); the READ side is what makes isolation observably active.
 
-### Emulated ReadCap ≠ application isolation — they COEXIST
+### The per-document ReadCap is now THE isolation path (item-level filter retired)
 
-`isolation.ts` is a **separate, deliberately non-merged** axis:
+Isolation is enforced by the **per-document ReadCap** (`caps.ts` + `read-filter.ts`)
+alone: the access unit is the DOCUMENT (`@graph` = repo), grants are explicit
+(`open` / `grantRead` / `makePublic`) and, for `protected`, driven by the
+**bilateral connection registry** (`connections.ts`). Because the consumer now
+writes **one document per entity** (`createEntityDoc` + `open` per entity), the
+per-document cap discriminates at entity granularity — the target's behaviour.
 
-| | ReadCap (`caps.ts` + `read-filter.ts`) | isolation (`isolation.ts`) |
-|---|---|---|
-| Unit | the DOCUMENT (`@graph` = repo) | the ITEM / record |
-| Question | does the principal HOLD this doc's read cap? | given WHO is connected to WHOM, may this principal see it? |
-| Models | NextGraph's native capability delivery (broker-enforced) | an application social-visibility policy, above the doc layer |
-| Grants | explicit, per-document (`grantRead` / `makePublic`) | implicit, from the connection graph + item scope |
-
-`isolation.ts` honors a visibility matrix (public = everyone; protected = owner +
-direct connections; private = owner only) with **pure** functions — no NextGraph,
-no React, zero domain. The consumer injects the connection graph (`Connections`)
-and the `ownerOf`/`scopeOf` accessors. The connection-derived `protected`
-visibility has no equivalent in the per-document cap model, so the two are not
-redundant. Each is a removable scaffold that disappears against a different piece
-of real infra (caps → native ReadCaps; isolation → real per-account social graph
-+ per-account wallets).
+The old **item-level application-visibility filter** (`isolation.ts`
+`applyIsolation`, a `Set`-of-records filter keyed on owner+scope) is **retired**
+from the consumer path: the app carries **no** access logic — it declares its
+identity and its bilateral connections and trusts the SDK. `isolation.ts` survives
+only as the home of the generic `Connections` interface (consumed by
+`connections.ts` / `caps.grantReadToConnections`) plus its own unit tests; 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 + curator (`inbox.ts`)
 
@@ -254,12 +267,17 @@ fork the broker ([`fork-inbox-fallback.md`](./fork-inbox-fallback.md)), the lib
   emulated 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 → concurrent deposits don't collide. `from` is
-  optional: pass `null` for an ANONYMOUS deposit; omit it to default to the
-  current polyfill user (`getCurrentUser`). This reproduces the protocol's
-  "identified if known, anonymous otherwise" — though the emulation stores
-  `from = null` as *absence of a triple*, it does not provide the target's
+  deposit is a unique RDF subject → 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)** play the **emulated CURATOR**: they read the
   deposits back via `docs.sparqlQuery`, JSON-parse each payload, sort by `ts`.
 - **`watch(targetInbox, onDeposits, { intervalMs })`** is the emulated watcher: it
@@ -297,9 +315,14 @@ into entries. Materialization is the natural **dedup / moderation point**.
   shared index.
 - **`submitToIndex(ref, opts?)`** — the SDK act "make this discoverable".
   Deposits `ref` into the index document's inbox via `inbox.post`. `from` follows
-  the inbox convention (anonymous when `null`). `ref` is **opaque** here — the
-  consumer serializes whatever locates the entity (e.g. an entity document NURI +
-  discovery metadata).
+  the inbox convention (bound to the current identity; anonymous when `null`).
+  `ref` is **opaque** here — the consumer serializes whatever locates the entity
+  (e.g. an entity document NURI + discovery metadata). **PUBLIC-ONLY guard:** when
+  `opts.doc` names the document being surfaced, a document under a non-public
+  (protected/private) read policy is **REFUSED** (`caps.governsRead(doc) &&
+  !caps.canRead(doc, null)`) — the global index is world-readable, so admitting a
+  governed doc's NURI would leak it past its scope. Proven in
+  `test/discovery.test.ts` case (d).
 - **`readIndex()`** — the EMULATED CURATOR. Reads every submission, **dedups by
   serialized `ref`** (the moderation point: a duplicate submission surfaces
   once), returns entries sorted by `ts`. `watchIndex(onEntries, opts?)` is the
diff --git a/packages/client/src/connections.ts b/packages/client/src/connections.ts
new file mode 100644
index 0000000..c32b0ab
--- /dev/null
+++ b/packages/client/src/connections.ts
@@ -0,0 +1,90 @@
+/**
+ * connections — a BILATERAL (two-sided, authenticated) connection registry.
+ *
+ * STOPGAP / polyfill-era. In the target, "connected" means the two wallets have
+ * *each* issued the other a capability (a mutual, cryptographically-authenticated
+ * link). A single side cannot manufacture the relationship. Here — one shared
+ * wallet, everything physically readable — the registry reproduces that property
+ * as data: a connection between `a` and `b` is materialized ONLY when BOTH sides
+ * have asserted it.
+ *
+ * ── Why bilateral (the adversarial finding this defends) ──────────────────────
+ * "protected = owner + connections" must not be bypassable by a reader who simply
+ * self-declares a connection to the owner. If a single directed assertion granted
+ * access, any principal could read any owner's protected documents by unilaterally
+ * claiming a link. So the registry keeps DIRECTED assertions and exposes as
+ * `neighbors(p)` only the principals `q` for which BOTH `assert(p → q)` AND
+ * `assert(q → p)` are present — the materialized two-sided link.
+ *
+ * ── Generic by construction ───────────────────────────────────────────────────
+ * Knows no application domain. The consumer maps its own relationship (accepted
+ * friendships, follows-back, …) onto directed assertions: each side asserts the
+ * other. Only when both assertions exist is the link live and does it drive a
+ * protected read grant (via {@link CapRegistry.grantReadToConnections}). Removed
+ * at migration, where a real mutual capability replaces the materialized link.
+ */
+
+import type { Connections } from "./isolation";
+import type { PrincipalId } from "./types";
+
+/**
+ * One directed connection assertion: `from` asserts a connection to `to`. A link
+ * is live (and grants protected read) only when the reverse assertion also
+ * exists. The consumer's own social graph is fed as these directed assertions.
+ */
+export interface ConnectionAssertion {
+  from: PrincipalId;
+  to: PrincipalId;
+}
+
+/**
+ * Accumulates directed assertions and exposes the BILATERAL neighbourhood. Both
+ * `assert(a → b)` and `assert(b → a)` must be present for `a`/`b` to be neighbours.
+ */
+export class ConnectionRegistry {
+  /** principal → the set of principals it has asserted a connection TO. */
+  private asserted = new Map<PrincipalId, Set<PrincipalId>>();
+
+  /** Record that `from` asserts a connection to `to` (one direction only). */
+  assert(from: PrincipalId, to: PrincipalId): void {
+    if (!from || !to || from === to) return;
+    let s = this.asserted.get(from);
+    if (!s) this.asserted.set(from, (s = new Set()));
+    s.add(to);
+  }
+
+  /** Record a batch of directed assertions. */
+  assertAll(assertions: Iterable<ConnectionAssertion>): void {
+    for (const { from, to } of assertions) this.assert(from, to);
+  }
+
+  /** Has `from` asserted a connection to `to` (one direction)? */
+  hasAsserted(from: PrincipalId, to: PrincipalId): boolean {
+    return this.asserted.get(from)?.has(to) ?? false;
+  }
+
+  /**
+   * The BILATERAL neighbours of `principal`: every `q` such that `principal` and
+   * `q` have each asserted the other. A unilateral (one-sided) assertion yields
+   * NO neighbour — the defence against self-declared connections.
+   */
+  neighbors(principal: PrincipalId): Set<PrincipalId> {
+    const out = new Set<PrincipalId>();
+    const outgoing = this.asserted.get(principal);
+    if (!outgoing) return out;
+    for (const to of outgoing) if (this.hasAsserted(to, principal)) out.add(to);
+    return out;
+  }
+
+  clear(): void {
+    this.asserted.clear();
+  }
+}
+
+/**
+ * Adapt a {@link ConnectionRegistry} to the {@link Connections} interface consumed
+ * by {@link CapRegistry.grantReadToConnections}. Only bilateral links surface.
+ */
+export function bilateralConnections(registry: ConnectionRegistry): Connections {
+  return { neighbors: (principal) => registry.neighbors(principal) };
+}
diff --git a/packages/client/src/discovery.ts b/packages/client/src/discovery.ts
index 163d8ab..53d27f2 100644
--- a/packages/client/src/discovery.ts
+++ b/packages/client/src/discovery.ts
@@ -41,6 +41,7 @@
 
 import * as inbox from "./inbox";
 import { ensureAccount, reservedAccount } from "./store-registry";
+import { getCaps } from "./polyfill";
 import type { Nuri, PrincipalId } from "./types";
 
 /**
@@ -66,11 +67,19 @@ export interface IndexEntry {
 /** Options for {@link submitToIndex}. */
 export interface SubmitOptions {
   /**
-   * Who is submitting. Omit (or pass `null`) for an ANONYMOUS submission; pass a
-   * principal id to identify the submitter. Defaults to the current polyfill user
-   * when the property is entirely absent (mirrors {@link inbox.post}).
+   * Who is submitting. Omit for the current identity, or pass `null` for an
+   * ANONYMOUS submission. `from` is BOUND to the current identity by the inbox
+   * (naming another principal is rejected as a spoof — see {@link inbox.post}).
    */
   from?: PrincipalId | null;
+  /**
+   * The NURI of the document being made discoverable. When given, the index
+   * enforces PUBLIC-ONLY: a document under a non-public (protected/private) read
+   * policy is REFUSED — the public index must never leak a governed document's
+   * NURI. Omit it only for a ref with no addressable document (rare); a governed
+   * doc always passes it so the guard can fire.
+   */
+  doc?: Nuri;
   /** Optional deposit timestamp (ms epoch). Omitted → `Date.now()`. Passing it
    *  keeps tests deterministic. */
   ts?: number;
@@ -100,8 +109,23 @@ async function indexInboxNuri(): Promise<Nuri> {
  * entry. GENERIC: `ref` is opaque here (the consumer serializes whatever a
  * client needs to later locate the entity — e.g. an entity document NURI plus
  * discovery metadata). `from` follows the inbox convention (anonymous if `null`).
+ *
+ * PUBLIC-ONLY: when `opts.doc` names the document being surfaced, a document under
+ * a non-public read policy (protected/private) is REFUSED — the global index is
+ * world-readable, so admitting a governed doc's NURI would leak it past its scope.
  */
 export async function submitToIndex(ref: unknown, opts?: SubmitOptions): Promise<void> {
+  const doc = opts?.doc;
+  if (doc !== undefined) {
+    const caps = getCaps();
+    // A governed doc is submittable ONLY if it is public (anonymous may read it).
+    if (caps.governsRead(doc) && !caps.canRead(doc, null)) {
+      throw new Error(
+        "[ng-eventually] submitToIndex: only PUBLIC documents may be submitted to " +
+          "the discovery index — a protected/private document must not be surfaced.",
+      );
+    }
+  }
   const target = await indexInboxNuri();
   await inbox.post(target, {
     payload: ref,
diff --git a/packages/client/src/inbox.ts b/packages/client/src/inbox.ts
index 2e7a35d..b715d55 100644
--- a/packages/client/src/inbox.ts
+++ b/packages/client/src/inbox.ts
@@ -90,11 +90,31 @@ function readBindings(result: unknown): Array<Record<string, { value: string }>>
  *
  * Appends `{ from, payload, ts }` into the inbox document via `docs.sparqlUpdate`
  * (the real injected `ng`). Each deposit is a fresh RDF subject in the inbox
- * graph, so concurrent deposits don't collide. `from` is optional: pass `null`
- * for an anonymous deposit; omit it entirely to default to the current user.
+ * graph, so concurrent deposits don't collide.
+ *
+ * `from` is BOUND TO THE CURRENT IDENTITY — it is authenticated, not
+ * caller-supplied. Omit it to stamp the current user; pass `null` to deposit
+ * ANONYMOUSLY (a legitimate choice — "identified if known, anonymous otherwise").
+ * A `from` naming ANOTHER principal is a SPOOF and is REJECTED: in the target the
+ * broker seals the sender from the wallet's own key, so a client cannot forge
+ * another's identity. (At migration this check is redundant — the seal enforces
+ * it — but until then it closes the spoof the shared wallet would otherwise allow.)
  */
 export async function post(targetInbox: Nuri, opts: PostOptions): Promise<void> {
-  const from = opts.from === undefined ? getCurrentUser() : opts.from;
+  const current = getCurrentUser();
+  let from: PrincipalId | null;
+  if (opts.from === undefined) {
+    from = current; // default: stamp the current identity
+  } else if (opts.from === null) {
+    from = null; // explicit anonymous deposit
+  } else if (opts.from === current) {
+    from = opts.from; // identifying as self — allowed
+  } else {
+    throw new Error(
+      "[ng-eventually] inbox.post: `from` must be the current identity or null " +
+        "(anonymous) — depositing as another principal is a spoof.",
+    );
+  }
   const ts = opts.ts ?? Date.now();
   const sid = await sessionId();
 
diff --git a/packages/client/src/polyfill.ts b/packages/client/src/polyfill.ts
index d7b8f3d..c410495 100644
--- a/packages/client/src/polyfill.ts
+++ b/packages/client/src/polyfill.ts
@@ -11,7 +11,7 @@
 import type { NgLike, UseShapeLike, PrincipalId } from "./types";
 import type { RegistrySession } from "./store-registry";
 import { CapRegistry } from "./caps";
-import type { Connections } from "./isolation";
+import { ConnectionRegistry, bilateralConnections } from "./connections";
 
 /**
  * Consumer-injected dependencies of the storeRegistry (polyfill-era). The
@@ -47,6 +47,9 @@ let registryDeps: Required<StoreRegistryDeps> | null = null;
 /** The emulated ReadCap/WriteCap registry. Empty until the app declares caps;
  *  while it has no read policy the read filter passes through (no regression). */
 let caps = new CapRegistry();
+/** The emulated BILATERAL connection registry. Accumulates directed assertions
+ *  (each authored by the asserting identity); only two-sided links materialize. */
+let connectionRegistry = new ConnectionRegistry();
 
 export function configure(c: EventuallyConfig): void {
   cfg = c;
@@ -108,24 +111,44 @@ export function getCaps(): CapRegistry {
 }
 
 /**
- * Declare the current session's CONNECTIONS to the SDK — the domain sharing act
- * "a protected document is readable by its owner AND that owner's connections".
- * The consumer knows who is connected to whom (its own social graph) and hands
- * that graph to the SDK; the SDK issues the corresponding read access on every
- * protected document it governs (public stays world-readable, private stays
- * owner-only). Re-call whenever the connection graph changes.
+ * Declare the CURRENT identity's own connections to the SDK — the domain sharing
+ * act "a protected document is readable by its owner AND that owner's connections".
  *
- * SDK-shaped: the consumer passes a {@link Connections} (who-is-connected-to-whom)
- * and gets access enforcement — it never touches a document NURI, a store id, or
- * the cap registry internals.
+ * AUTHENTICATED / BILATERAL. Each entry in `peers` is a principal the CURRENT user
+ * (`getCurrentUser()`, or an explicit `as`) asserts a connection to. The lib
+ * records that assertion as authored BY the current identity — a session can only
+ * ever assert its OWN side. A protected read is granted between two principals only
+ * when BOTH have asserted the other (a materialized two-sided link). So a reader
+ * who unilaterally self-declares a connection to an owner gets NOTHING: the owner
+ * never asserted them back. Public stays world-readable; private stays owner-only.
+ * Re-callable whenever the connection graph changes (additive + idempotent).
+ *
+ * SDK-shaped: the consumer passes principals only — never a document NURI, a store
+ * id, or the cap registry internals. `as` names the asserting identity explicitly
+ * (defaults to the current user); the consumer normally omits it.
  */
-export function declareConnections(connections: Connections): void {
-  caps.grantReadToConnections((owner) => connections.neighbors(owner));
+export function declareConnections(peers: Iterable<PrincipalId>, as?: PrincipalId): void {
+  const self = as ?? currentUser;
+  if (self) for (const peer of peers) connectionRegistry.assert(self, peer);
+  // Re-derive protected grants from the CURRENT bilateral view (only two-sided
+  // links surface as neighbours). Idempotent: grants only ever accumulate.
+  caps.grantReadToConnections((owner) => connectionRegistry.neighbors(owner));
+}
+
+/** @internal — the bilateral connection registry (mainly for tests / adapters). */
+export function getConnectionRegistry(): ConnectionRegistry {
+  return connectionRegistry;
+}
+
+/** The current bilateral connection view (only two-sided links surface). */
+export function getConnections() {
+  return bilateralConnections(connectionRegistry);
 }
 
 /** Reset all emulated caps (mainly for tests / fresh sessions). */
 export function resetCaps(): void {
   caps = new CapRegistry();
+  connectionRegistry = new ConnectionRegistry();
 }
 
 // Cap surface — polyfill-era (caps are emulated now; native at migration).
diff --git a/packages/client/test/connections.test.ts b/packages/client/test/connections.test.ts
new file mode 100644
index 0000000..f3d5089
--- /dev/null
+++ b/packages/client/test/connections.test.ts
@@ -0,0 +1,60 @@
+/**
+ * ConnectionRegistry — BILATERAL connection materialization (T03.h).
+ *
+ * A connection is live only when BOTH sides have asserted the other. A unilateral
+ * (self-declared) assertion yields no neighbour — the defence against a reader who
+ * fakes a connection to an owner to read that owner's protected documents.
+ */
+import { test, expect } from "bun:test";
+import { ConnectionRegistry, bilateralConnections } from "../src/connections";
+
+test("a UNILATERAL assertion yields NO neighbour", () => {
+  const reg = new ConnectionRegistry();
+  reg.assert("mallory", "alice"); // mallory self-declares; alice never asserts back
+  expect([...reg.neighbors("mallory")]).toEqual([]);
+  expect([...reg.neighbors("alice")]).toEqual([]);
+});
+
+test("a BILATERAL assertion (both sides) materializes the link", () => {
+  const reg = new ConnectionRegistry();
+  reg.assert("alice", "bob");
+  reg.assert("bob", "alice");
+  expect([...reg.neighbors("alice")]).toEqual(["bob"]);
+  expect([...reg.neighbors("bob")]).toEqual(["alice"]);
+});
+
+test("mixed: only the reciprocated peers surface", () => {
+  const reg = new ConnectionRegistry();
+  reg.assert("alice", "bob"); // reciprocated below
+  reg.assert("bob", "alice");
+  reg.assert("alice", "carol"); // NOT reciprocated by carol
+  reg.assert("dave", "alice"); // dave asserts alice, alice never asserts dave
+  expect([...reg.neighbors("alice")].sort()).toEqual(["bob"]);
+});
+
+test("self-assertion and empty are ignored", () => {
+  const reg = new ConnectionRegistry();
+  reg.assert("alice", "alice");
+  reg.assert("", "bob");
+  reg.assert("alice", "");
+  expect([...reg.neighbors("alice")]).toEqual([]);
+});
+
+test("bilateralConnections adapts to the Connections interface", () => {
+  const reg = new ConnectionRegistry();
+  reg.assertAll([
+    { from: "alice", to: "bob" },
+    { from: "bob", to: "alice" },
+  ]);
+  const conns = bilateralConnections(reg);
+  expect([...conns.neighbors("alice")]).toEqual(["bob"]);
+  expect([...conns.neighbors("carol")]).toEqual([]);
+});
+
+test("clear() removes all assertions", () => {
+  const reg = new ConnectionRegistry();
+  reg.assert("alice", "bob");
+  reg.assert("bob", "alice");
+  reg.clear();
+  expect([...reg.neighbors("alice")]).toEqual([]);
+});
diff --git a/packages/client/test/discovery.test.ts b/packages/client/test/discovery.test.ts
index ddf1b06..79c0131 100644
--- a/packages/client/test/discovery.test.ts
+++ b/packages/client/test/discovery.test.ts
@@ -7,6 +7,8 @@ import {
   resetStoreRegistry,
   resetConfig,
   setCurrentUser,
+  getCaps,
+  resetCaps,
 } from "../src/polyfill";
 import { resetRegistryCache, ensureAccount } from "../src/store-registry";
 import type { RegistrySession } from "../src/store-registry";
@@ -20,6 +22,7 @@ afterAll(() => {
   resetConfig();
   resetStoreRegistry();
   setCurrentUser(null);
+  resetCaps();
 });
 
 test("throws a clear error when configureStoreRegistry() was not called", async () => {
@@ -171,6 +174,7 @@ test("submitToIndex creates the @index special account on first sight (3 docs)",
 });
 
 test("submit → read round-trips the reference as an index entry", async () => {
+  setCurrentUser("alice"); // `from` is bound to the current identity
   const ref = { nuri: "did:ng:o:event1", title: "Concert au parc" };
   await submitToIndex(ref, { from: "alice", ts: 100 });
   const entries = await readIndex();
@@ -197,8 +201,9 @@ test("a reference submitted by A is discovered by a NON-connected reader via the
 
 test("readIndex deduplicates identical references (materialization moderation point)", async () => {
   const ref = { nuri: "did:ng:o:dup", title: "Twice" };
-  await submitToIndex(ref, { from: "alice", ts: 100 });
-  await submitToIndex(ref, { from: "bob", ts: 200 }); // duplicate reference
+  // Anonymous submissions (dedup keys on the ref, not the submitter).
+  await submitToIndex(ref, { from: null, ts: 100 });
+  await submitToIndex(ref, { from: null, ts: 200 }); // duplicate reference
   const entries = await readIndex();
   expect(entries).toHaveLength(1); // surfaced once
 });
@@ -209,6 +214,30 @@ test("from: null makes an anonymous submission", async () => {
   expect(entries[0]!.from).toBeNull();
 });
 
+// (d) PUBLIC-ONLY: a protected/private document must NOT be submittable to the
+// world-readable discovery index; a public (or ungoverned) document is fine.
+test("(d) submitToIndex refuses a PROTECTED/PRIVATE document (public-only)", async () => {
+  resetCaps();
+  // A PROTECTED and a PRIVATE governed document, and a PUBLIC one.
+  getCaps().open("did:ng:o:prot", "protected", "alice");
+  getCaps().open("did:ng:o:priv", "private", "alice");
+  getCaps().open("did:ng:o:pub", "public", "alice");
+
+  // Submitting the protected doc's NURI is REJECTED.
+  await expect(
+    submitToIndex({ nuri: "did:ng:o:prot" }, { from: null, doc: "did:ng:o:prot" }),
+  ).rejects.toThrow(/PUBLIC|public-only|protected\/private/i);
+  // Private too.
+  await expect(
+    submitToIndex({ nuri: "did:ng:o:priv" }, { from: null, doc: "did:ng:o:priv" }),
+  ).rejects.toThrow(/PUBLIC|public-only|protected\/private/i);
+  // The PUBLIC document passes.
+  await submitToIndex({ nuri: "did:ng:o:pub" }, { from: null, doc: "did:ng:o:pub", ts: 1 });
+  const entries = await readIndex();
+  expect(entries.map((e) => (e.ref as { nuri: string }).nuri)).toEqual(["did:ng:o:pub"]);
+  resetCaps();
+});
+
 test("INDEX_ACCOUNT lives in the reserved namespace (no typed username can equal it)", () => {
   // The index account occupies a key no user input can produce: it is prefixed
   // with a NUL control char, which a user cannot type into a username field and
diff --git a/packages/client/test/inbox.test.ts b/packages/client/test/inbox.test.ts
index f10e7cf..4c96f41 100644
--- a/packages/client/test/inbox.test.ts
+++ b/packages/client/test/inbox.test.ts
@@ -134,6 +134,7 @@ beforeEach(() => {
 });
 
 test("post writes via the real injected ng.sparql_update (not makeNg), scoped to the inbox", async () => {
+  setCurrentUser("alice"); // `from` is bound to the current identity
   await post(TARGET, { from: "alice", payload: { kind: "join" }, ts: 100 });
   expect(fake.sparql_update).toHaveBeenCalledTimes(1);
   const call = fake.sparql_update.mock.calls[0]!;
@@ -143,12 +144,29 @@ test("post writes via the real injected ng.sparql_update (not makeNg), scoped to
 });
 
 test("post → read round-trips payload, from and ts", async () => {
+  setCurrentUser("alice"); // `from` is bound to the current identity
   await post(TARGET, { from: "alice", payload: { kind: "join", n: 3 }, ts: 100 });
   const deposits = await read(TARGET);
   expect(deposits).toHaveLength(1);
   expect(deposits[0]).toEqual({ from: "alice", payload: { kind: "join", n: 3 }, ts: 100 });
 });
 
+// (c) `from` is BOUND to the current identity — a spoof (naming another
+// principal) is REJECTED; identifying as self or anonymous (null) is allowed.
+test("(c) post rejects a spoofed `from` (naming another principal); self/null allowed", async () => {
+  setCurrentUser("alice");
+  // SPOOF: alice tries to deposit AS bob → rejected.
+  await expect(post(TARGET, { from: "bob", payload: { x: 1 }, ts: 1 })).rejects.toThrow(
+    /spoof|current identity/i,
+  );
+  // Identifying as self → allowed.
+  await post(TARGET, { from: "alice", payload: { x: 2 }, ts: 2 });
+  // Explicit anonymous → allowed.
+  await post(TARGET, { from: null, payload: { x: 3 }, ts: 3 });
+  const froms = (await read(TARGET)).map((d) => d.from);
+  expect(froms).toEqual(["alice", null]);
+});
+
 test("from is optional — omitting it defaults to the current user", async () => {
   setCurrentUser("bob");
   await post(TARGET, { payload: { hi: 1 }, ts: 200 });
diff --git a/packages/client/test/isolation-active.test.ts b/packages/client/test/isolation-active.test.ts
index cddf8ce..f60b735 100644
--- a/packages/client/test/isolation-active.test.ts
+++ b/packages/client/test/isolation-active.test.ts
@@ -1,12 +1,15 @@
 /**
- * ReadCap ACTIVE — end-to-end proof that isolation is enforced by the emulated
- * cap registry (not merely by the app's social isolation filter).
+ * ReadCap ACTIVE (T03.h) — end-to-end proof that the emulated SDK enforces
+ * per-DOCUMENT isolation, driven by per-entity documents + BILATERAL connections.
  *
- * This mirrors exactly what the app's storeRegistry wrapper does: create an
- * entity document through the REAL registry (`createEntityDoc`), then declare
- * its cap policy via `getCaps().open(doc, scope, owner)`. The read filter then
- * hides one owner's private document from another principal — the faithful
- * per-DOCUMENT NextGraph behavior.
+ * Mirrors exactly what the app does: create an entity document through the REAL
+ * registry (`createEntityDoc`), declare its cap policy via
+ * `getCaps().open(doc, scope, owner)`, set the current identity, and declare
+ * connections as the CURRENT identity's own peers (authenticated, bilateral). The
+ * read filter then discriminates:
+ *   (a) unconnected principal denied a PROTECTED doc; granted after a BILATERAL
+ *       connection; PUBLIC readable throughout — via the ACTIVE ReadCap.
+ *   (b) a UNILATERAL / self-declared connection grants NOTHING.
  */
 import { test, expect, mock, afterAll } from "bun:test";
 import { createEntityDoc, resetRegistryCache } from "../src/store-registry";
@@ -18,15 +21,16 @@ import {
   resetConfig,
   getCaps,
   resetCaps,
+  setCurrentUser,
   declareConnections,
 } from "../src/polyfill";
 import { filterReadable } from "../src/read-filter";
-import { connectionsFromLinks } from "../src/isolation";
 
 afterAll(() => {
   resetConfig();
   resetStoreRegistry();
   resetCaps();
+  setCurrentUser(null);
 });
 
 const SESSION: RegistrySession = { sessionId: "sid", privateStoreId: "PRIV" };
@@ -42,75 +46,78 @@ function inject() {
   configureStoreRegistry({ getSession: async () => SESSION, normalizeUser: (u) => u.trim() });
   resetRegistryCache();
   resetCaps();
+  setCurrentUser(null);
   return ng;
 }
 
 test("ReadCap active: a private entity doc created via the real registry is hidden from another principal", async () => {
   inject();
 
-  // Alice creates a PRIVATE entity document via the REAL store-registry, then
-  // (as the app wrapper does) declares its cap policy: owner-only read.
   const aliceDoc = await createEntityDoc("alice", "private");
   getCaps().open(aliceDoc, "private", "alice");
 
-  // Bob creates a PUBLIC entity document (world-readable).
   const bobDoc = await createEntityDoc("bob", "public");
   getCaps().open(bobDoc, "public", "bob");
 
-  // The reactive set as the broker would deliver it (mono-store: items carry
-  // their @graph = the document they live in).
   const items = [
     { "@graph": aliceDoc, "@id": "a1", label: "alice-private" },
     { "@graph": bobDoc, "@id": "b1", label: "bob-public" },
   ];
 
-  // Bob cannot read alice's private doc; he CAN read the public one and, since
-  // the read filter is now under a policy, alice's private item is filtered out.
-  const bobView = filterReadable(items, getCaps(), "bob").map((i) => i["@id"]);
-  expect(bobView).toEqual(["b1"]);
-
-  // Alice reads her own private doc AND the public one.
-  const aliceView = filterReadable(items, getCaps(), "alice").map((i) => i["@id"]);
-  expect(aliceView.sort()).toEqual(["a1", "b1"]);
-
-  // Anonymous sees only the public doc.
-  const anonView = filterReadable(items, getCaps(), null).map((i) => i["@id"]);
-  expect(anonView).toEqual(["b1"]);
-
-  // Sanity: this is the REGISTRY talking, not app-level isolation — the caps
-  // registry has an active read policy.
+  expect(filterReadable(items, getCaps(), "bob").map((i) => i["@id"])).toEqual(["b1"]);
+  expect(filterReadable(items, getCaps(), "alice").map((i) => i["@id"]).sort()).toEqual(["a1", "b1"]);
+  expect(filterReadable(items, getCaps(), null).map((i) => i["@id"])).toEqual(["b1"]);
   expect(getCaps().hasReadPolicy()).toBe(true);
 });
 
-test("ReadCap active: a PROTECTED entity doc is hidden from an unconnected principal, revealed after they connect, PUBLIC readable regardless", async () => {
+// (a) protected hidden while unconnected → revealed after a BILATERAL connection;
+//     public readable regardless — all through the ACTIVE ReadCap.
+test("(a) PROTECTED doc: hidden unconnected, revealed after BILATERAL connection, PUBLIC always readable", async () => {
   inject();
 
-  // Alice creates a PROTECTED entity document + a PUBLIC one, declaring the caps
-  // exactly as the app wrapper does (createEntityDoc → getCaps().open).
   const aliceProtected = await createEntityDoc("alice", "protected");
   getCaps().open(aliceProtected, "protected", "alice");
   const alicePublic = await createEntityDoc("alice", "public");
   getCaps().open(alicePublic, "public", "alice");
 
   const items = [
-    { "@graph": aliceProtected, "@id": "p1", label: "alice-protected" },
-    { "@graph": alicePublic, "@id": "u1", label: "alice-public" },
+    { "@graph": aliceProtected, "@id": "p1" },
+    { "@graph": alicePublic, "@id": "u1" },
   ];
+  const view = (u: string) => filterReadable(items, getCaps(), u).map((i) => i["@id"]).sort();
 
-  const view = (user: string) => filterReadable(items, getCaps(), user).map((i) => i["@id"]).sort();
-
-  // BEFORE any connection: bob (unconnected) sees ONLY alice's public item, NOT
-  // her protected one. Alice sees both.
+  // BEFORE any connection: bob sees only the public item.
   expect(view("bob")).toEqual(["u1"]);
   expect(view("alice")).toEqual(["p1", "u1"]);
 
-  // The app declares the CONNECTIONS graph to the SDK (domain sharing act): now
-  // alice and bob are connected. The SDK issues the protected doc's read cap to
-  // bob (owner's connection). Public is unaffected.
-  declareConnections(connectionsFromLinks([{ a: "alice", b: "bob" }]));
+  // BILATERAL: alice asserts bob AND bob asserts alice → the link materializes and
+  // the SDK issues the protected doc's read cap to bob.
+  declareConnections(["bob"], "alice");
+  declareConnections(["alice"], "bob");
 
-  // AFTER connecting: bob reads alice's PROTECTED item too; PUBLIC still readable.
   expect(view("bob")).toEqual(["p1", "u1"]);
-  // A THIRD, still-unconnected principal (carol) sees only the public one.
+  // A third, unconnected principal still sees only the public one.
   expect(view("carol")).toEqual(["u1"]);
 });
+
+// (b) A UNILATERAL / self-declared connection must NOT grant protected read.
+test("(b) a UNILATERAL / self-declared connection grants NO protected read", async () => {
+  inject();
+
+  const aliceProtected = await createEntityDoc("alice", "protected");
+  getCaps().open(aliceProtected, "protected", "alice");
+  const items = [{ "@graph": aliceProtected, "@id": "p1" }];
+  const view = (u: string) => filterReadable(items, getCaps(), u).map((i) => i["@id"]);
+
+  // The ATTACKER (mallory) self-declares a connection to alice — a UNILATERAL
+  // assertion authored by mallory. Alice NEVER asserts mallory back.
+  declareConnections(["alice"], "mallory");
+  expect(view("mallory")).toEqual([]); // still denied — no bilateral link
+
+  // Even if alice connects to bob (a different, legitimate bilateral link),
+  // mallory's one-sided assertion still grants nothing.
+  declareConnections(["bob"], "alice");
+  declareConnections(["alice"], "bob");
+  expect(view("mallory")).toEqual([]);
+  expect(view("bob")).toEqual(["p1"]);
+});