fix(app): gate directory-store mutations for remote SSE events (#1539)

packages/app-bundle/manifest.json

@@ -165,17 +165,19 @@
     "packages/app/src/context/models.tsx": "8904525767b36ed5ba93e85a0fddb9bf737a8d066dfff084380ce1a67182f535",
     "packages/app/src/context/platform.tsx": "edd9b1773feb5c084b922a57b6914f6a473eed558b44f9de0eeb1c4d4e2b49da",
     "packages/app/src/context/server-sdk.test.ts": "48ce5243c8c5d42c23c8eadf9eecac777c9330ac1f4d81953042d5ef7d264bd7",
-    "packages/app/src/context/server-sdk.tsx": "130d54ea73c7269c0409dee6236b61145493d0c5f562750f8df94a56c10ed8be",
+    "packages/app/src/context/server-sdk.tsx": "a3f51fc8a17da40869cd21aecebc5e06bd2e2ba5d323b4aa07909a2646df9549",
     "packages/app/src/context/server-session.test.ts": "a76d24b0d36d7c6c9ce187d2eb5bba78c90774184adc0398559ee1a417674516",
     "packages/app/src/context/server-session.ts": "4d85011c9ff81cf0470633f6f27cd9f11c234294c31e2c77a990aad135d317ab",
-    "packages/app/src/context/server-sync.tsx": "14396d7402d697ab9a10744c9e428b96e483f3a9620a0415246fa840596fd8ed",
+    "packages/app/src/context/server-sync.tsx": "94c16dfb25bf8cec340bdc31bef5e875c31a4c42af7076179bf69da4d1586889",
     "packages/app/src/context/server.tsx": "08e978e4b4b3094221a2a0b92e069f39cbedb6d6cf95935881e21cde52265ee2",
     "packages/app/src/context/session-mirror.test.ts": "65e6d6474e4e67f2da194047140c8c8aac04fe0cc9926441468e53fabc48db96",
     "packages/app/src/context/session-mirror.ts": "b98de060f2b06e6f9a48b1f69ed408f12086c626d90c7dd22029a4ee732260e2",
     "packages/app/src/context/session-warm.test.ts": "b862625f1e418913a982b368573f5abf07aaf6e1a63ded8296a1d43ef164ec34",
     "packages/app/src/context/session-warm.ts": "d4184b8f0a090b0a011cdf7b6e80d5f765b6f7acd834eaad064e39ca8e0eb7bc",
     "packages/app/src/context/settings.tsx": "19e078e81620ffa21a92797335009b84d4311485a37c5ede2f76906b734292ad",
     "packages/app/src/context/split.tsx": "891aeb290b369b327a63ce548dcaab1daca08e41fab430648787be7f84e53ec0",
+    "packages/app/src/context/sse-origin.test.ts": "71cd3aa996a51d7e99236a49cede4769e520e20e53f57c6920fe441f2abb0c7d",
+    "packages/app/src/context/sse-origin.ts": "da9a231907dc50d87cf01758177bee0d4a0b0165d8adb5e152db8eca29dfd9f5",
     "packages/app/src/context/stream-gap.test.ts": "b7203445564f44fd1d966ef684a11cb9b5ec567d9ab54f1b7617726fdf44d3f5",
     "packages/app/src/context/stream-gap.ts": "2fd8eba30a6112cebf38e33c9418ab2b7d9c9d466f76729d828d5ab52d56c5ec",
     "packages/app/src/context/tab-migration.ts": "569e69cd3425917c7e195f91c3a838abea68b616267ea7511f3ccf01d94ac01e",
@@ -641,7 +643,7 @@
     "packages/app/src/components/session/preview-human-write-gate.ts": "4c4b1cf258a06b0012d722add0125ecb77a0f4e463dd95d193f21e5e73541098",
     "packages/app/src/components/session/session-chats-dropdown.test.ts": "b5f178bea1b52788d6f794d09ccf7ff81f745633ad59e2d438cfc80b96acde55",
     "packages/app/src/components/session/session-context-tab.tsx": "227243b178b517f067d9ae0ae0eec3c559beeb6681828158b0600a17e98e7f81",
-    "packages/app/src/components/session/session-fleet-peers.test.ts": "67e03d6f0be79f5d08cb293af2c8d7e1100e5c49d7fd86ce5c7ced1eea93f1d7",
+    "packages/app/src/components/session/session-fleet-peers.test.ts": "c3e5404ff868b37706a4963c83565de022443ea09e350ee60200b89cc5dba61c",
     "packages/app/src/components/session/session-fleet-peers.ts": "1c9e846668adcff0852a66a6961e393fb9e0cc91dc4103017d70cbad269f791c",
     "packages/app/src/components/session/session-header.tsx": "c8207d714f01d4fe9f8731b410ff0359e4f9b9f7815967cc654060944af8933e",
     "packages/app/src/components/session/session-new-view.tsx": "9510a4f550a3f0d4791e98e8025666f09d70a60fb66f193e48ee61feddae5a57",
@@ -674,7 +676,7 @@
     "packages/app/src/components/ui/drawer.tsx": "76574ca4c6997209f37a766a61000d707332a9a857f6ea8100a3cee1be58d65c",
     "packages/app/src/context/global-sync/bootstrap.test.ts": "ed66b4c0427d51c015fd286dd63c2cc24a25391320366d75e28634334d70e366",
     "packages/app/src/context/global-sync/child-store.ts": "3fde298a6cda8e96efc22bccee4ef124e139abd6ec28510363c78f702bf70db9",
-    "packages/app/src/context/global-sync/event-reducer.test.ts": "0528ed45952107b3ca174e72fd0b920191dbbd49eb795c4dff63cf89c2c91c0e",
+    "packages/app/src/context/global-sync/event-reducer.test.ts": "2d8a77b327403c99fb78d15cb720e6a4e0a5e9479a5fbf1f714455b66e87d0a2",
     "packages/app/src/context/global-sync/event-reducer.ts": "9c26e9e83709e56c57b228a03186df6bf1a52a073c4b7e721853956ee0da6142",
     "packages/app/src/context/global-sync/session-cache.test.ts": "e3c66ef76ff20a416f3b2d72041acd66c2a65da57ded92cbcb381ab71474285f",
     "packages/app/src/context/global-sync/session-cache.ts": "70f60c37ab9ffcb5ac0778f4962d88f0e7c6fb61fc39a18bda28942322605316",
@@ -838,7 +840,7 @@
     "packages/app/src/pages/session/timeline/projection.ts": "36ab006523de7b695b33d26a0a03b59db9e148b7e979c36f63970cbcb8bcaca2",
     "packages/app/src/pages/session/timeline/rows-current.test.ts": "b6a2d9671cfba970990b36d9ef0d1f107efcee59f0a9863f1280526116299095",
     "packages/app/src/pages/session/timeline/rows.ts": "68581190ff5e51d2dc398298c705fbb5dfdefb7eb4cecf98f1da6ae0bd171f18",
-    "packages/app/src/pages/session/timeline/session-header-provenance.test.ts": "b6ca7ffde2ef5d02b09968c20b5027ceab45506af8b1a49dd3f6c8ffe5912312",
+    "packages/app/src/pages/session/timeline/session-header-provenance.test.ts": "4bdf201c16d00eb60957d0ad9b40dafd69410a4b46deb0634e16da26103be1da",
     "packages/app/src/pages/session/timeline/session-header-provenance.ts": "7b73833aa5a3530c704edef2ca38cb6730aaaa729c23e06b6227788fb5c7e324",
     "packages/app/src/pages/session/timeline/smooth-scroll.test.ts": "79d3bba42ad83c3ab80df907e0acf08665a38c4809468e6c12ac9fcf5e94682f",
     "packages/app/src/pages/session/timeline/smooth-scroll.ts": "3f2782f52e36acf86398fb444bc53fcfec2fec9a0684613466ff7d24b8bceb26",
@@ -893,10 +895,10 @@
     "packages/ui/src/v2/components/text-shimmer-v2.tsx"
   ],
   "exceptions": [],
-  "extracted_at": "2026-09-24T13:51:39.015Z",
+  "extracted_at": "2026-09-24T19:01:26.321Z",
   "per_package": {
     "packages/app": {
-      "A": 201,
+      "A": 203,
       "M": 156,
       "D": 0
     },
@@ -942,7 +944,7 @@
     }
   },
   "counts": {
-    "overlay_total": 871,
+    "overlay_total": 873,
     "deletions": 7,
     "server_coupled": 0
   },
@@ -1115,6 +1117,8 @@
     "packages/app/src/context/session-warm.ts": "A",
     "packages/app/src/context/settings.tsx": "M",
     "packages/app/src/context/split.tsx": "A",
+    "packages/app/src/context/sse-origin.test.ts": "A",
+    "packages/app/src/context/sse-origin.ts": "A",
     "packages/app/src/context/stream-gap.test.ts": "A",
     "packages/app/src/context/stream-gap.ts": "A",
     "packages/app/src/context/tab-migration.ts": "M",

packages/app-bundle/overlay/packages/app/src/components/session/session-fleet-peers.test.ts

@@ -93,6 +93,40 @@ describe("#1525 mergePeerSessions — dedupe (local wins) + sort by last activit
     const local = [mk("a", 5), mk("b", 9)]
     expect(mergePeerSessions(local, []).map((s) => s.id)).toEqual(["b", "a"])
   })
+
+  // #1539 regression: when the SSE fan-in contaminated the directory store, a
+  // remote session ended up in the local `activeSessions` array WITHOUT its
+  // `amicode_owner` tag. On the next dropdown open, `mergePeerSessions` saw the
+  // local (untagged) copy and the projection (tagged) copy — local wins, so the
+  // badge-carrying projection copy was dropped. The fix gates the directory store
+  // so remote events never insert there; this test guards the dedup behavior that
+  // was being exploited by the contamination.
+  test("#1539 regression: contaminated local copy (no amicode_owner) wins over badged projection copy", () => {
+    // Simulate the contamination scenario: same session in local (no tag) and
+    // projection (with tag). The local copy should win, which is correct behavior
+    // — the fix prevents the contamination from happening in the first place.
+    const contaminated = mk("ses_remote", 5) // no amicode_owner (the bug)
+    const fromProjection = mk("ses_remote", 5, studioTag) // has the badge
+    const out = mergePeerSessions([contaminated], [fromProjection])
+    expect(out).toHaveLength(1)
+    // Local wins → badge is lost. This is CORRECT dedup behavior — the fix is
+    // to prevent `contaminated` from ever reaching the local store.
+    expect(out[0].amicode_owner).toBeUndefined()
+    expect(deriveSessionBadge(out[0])).toBeUndefined()
+  })
+
+  test("#1539 fixed: when directory store is clean, projection badge persists through dedup", () => {
+    // After the fix: the remote session is ONLY in the projection (with badge),
+    // never contaminated into the local store. The dropdown merges correctly.
+    const localSessions = [mk("ses_local", 5)]
+    const projectionPeers = [mk("ses_remote", 3, studioTag)]
+    const out = mergePeerSessions(localSessions, projectionPeers)
+    expect(out).toHaveLength(2)
+    const remote = out.find((s) => s.id === "ses_remote")!
+    expect(remote.amicode_owner).toBeDefined()
+    expect(remote.amicode_owner!.is_local).toBe(false)
+    expect(deriveSessionBadge(remote)).toBe("JJ's Mac Studio")
+  })
 })
 
 // #1537 B2a (AC4): owner-routed OPEN. `resolveDropdownOpenAction` is the pure

packages/app-bundle/overlay/packages/app/src/context/global-sync/event-reducer.test.ts

@@ -614,4 +614,46 @@ describe("applyDirectoryEvent", () => {
     expect(lspLoads).toBe(1)
   })
 
+  // #1539: the directory store is local-only. The gate in server-sync.tsx checks
+  // `event.origin` and skips `applyDirectoryEvent` for remote-origin events. This
+  // test verifies the gate's contract: a remote-origin event WOULD mutate the
+  // store if the gate weren't there, proving the gate is necessary.
+  test("#1539 gate contract: session.created WOULD insert into the store (the gate prevents this for remote events)", () => {
+    const [store, setStore] = createStore(baseState({ session: [], sessionTotal: 0 }))
+    const remoteSession = rootSession({ id: "ses_remote" })
+
+    // Without the gate, applyDirectoryEvent inserts the session:
+    applyDirectoryEvent({
+      event: { type: "session.created", properties: { info: remoteSession } },
+      store,
+      setStore,
+      push() {},
+      directory: "/tmp",
+      loadLsp() {},
+    })
+    expect(store.session).toHaveLength(1)
+    expect(store.sessionTotal).toBe(1)
+
+    // The gate in server-sync.tsx: `if (isRemote) return` — skips this call.
+    // A remote-origin event with `origin: "studio"` never reaches here.
+    // This test documents what the gate prevents.
+  })
+
+  test("#1539 gate contract: session.updated WOULD upsert into the store (the gate prevents this for remote events)", () => {
+    const [store, setStore] = createStore(baseState({ session: [], sessionTotal: 0 }))
+    const remoteSession = rootSession({ id: "ses_remote" })
+
+    // Without the gate, session.updated inserts a previously-unknown session:
+    applyDirectoryEvent({
+      event: { type: "session.updated", properties: { info: remoteSession } },
+      store,
+      setStore,
+      push() {},
+      directory: "/tmp",
+      loadLsp() {},
+    })
+    expect(store.session).toHaveLength(1)
+    // The gate prevents this for events with `origin: "studio"`.
+  })
+
 })

packages/app-bundle/overlay/packages/app/src/context/server-sdk.tsx

@@ -12,14 +12,15 @@ import { ServerConnection, useServer } from "./server"
 import { createRefCountMap } from "@/utils/refcount"
 import { useGlobal } from "./global"
 import { ServerScope } from "@/utils/server-scope"
+import { parseCursorNamespaces, resolveEventOrigin } from "./sse-origin"
 import { detectServerProtocol, type ServerProtocol } from "@/utils/server-protocol"
 import { createCompatibleApi, type CompatibleApi } from "@/utils/server-compat"
 
 const isAbortError = (error: unknown) =>
   error !== null && typeof error === "object" && "name" in error && error.name === "AbortError"
 
 const isStreamClosed = (error: unknown, signal?: AbortSignal) => isAbortError(error) || signal?.aborted === true
-export type ServerEvent = Event & { current?: OpenCodeEvent }
+export type ServerEvent = Event & { current?: OpenCodeEvent; origin?: string }
 type QueuedServerEvent = { directory: string; payload: ServerEvent }
 /** A minimal fetch call signature. Newer lib types make `typeof fetch` require
  *  a `preconnect` member our plain wrappers don't implement (lib drift);
@@ -347,6 +348,10 @@ function createServerSdkContextBase(server: ServerConnection.Any, scope: ServerS
       }
     }
   }
+  // #1539: track the parsed composite cursor to detect event origin (local vs
+  // remote peer). Initialized from the persisted cursor so the first event
+  // after reconnect diffs correctly.
+  let previousParsedCursor = parseCursorNamespaces(lastEventID)
   const sseFetch: FetchLike = (input, init) => {
     const base = eventFetch ?? globalThis.fetch
     try {
@@ -501,7 +506,17 @@ function createServerSdkContextBase(server: ServerConnection.Any, scope: ServerS
               continue
             }
             trackEventID(legacy ? event.payload : (event as { id?: string }))
-            if (enqueueServerEvent(queue, { directory, payload })) schedule()
+            // #1539: resolve origin from the composite cursor diff. Fleet-of-one
+            // (bare scalar id) returns undefined immediately — zero overhead.
+            const sseId: string | undefined = legacy
+              ? (event.payload as { id?: string }).id
+              : (event as { id?: string }).id
+            const resolved = resolveEventOrigin(sseId, previousParsedCursor)
+            previousParsedCursor = resolved.cursor
+            const taggedPayload: ServerEvent = resolved.origin !== undefined
+              ? { ...payload, origin: resolved.origin }
+              : payload
+            if (enqueueServerEvent(queue, { directory, payload: taggedPayload })) schedule()
 
             if (Date.now() - yielded < STREAM_YIELD_MS) continue
             yielded = Date.now()
@@ -537,6 +552,7 @@ function createServerSdkContextBase(server: ServerConnection.Any, scope: ServerS
 
   const clearGlobalStreamCursor = () => {
     lastEventID = undefined
+    previousParsedCursor = {}
     try {
       sessionStorage.removeItem(CURSOR_KEY)
     } catch {

packages/app-bundle/overlay/packages/app/src/context/server-sync.tsx

@@ -548,11 +548,17 @@ export function createServerSyncContextInner(serverSDK: ServerSDK) {
     const event = e.details
     const eventType: string = event.type
     const recent = bootingRoot || Date.now() - bootedAt < 1500
+    // #1539: remote-origin events must NOT mutate the local directory store.
+    // The origin field is set by the SSE loop when the event came from a remote
+    // peer's namespace in the fan-in composite cursor. `undefined` = local.
+    const isRemote = typeof event.origin === "string"
 
     if (event.current) session.applyV2(event.current)
     session.apply(event)
     if (event.type === "session.created" || event.type === "session.updated" || event.type === "session.deleted") {
-      homeSessions.apply(event)
+      // #1539: homeSessions feeds into the session list that mergePeerSessions
+      // deduplicates against; remote events contaminate it the same way.
+      if (!isRemote) homeSessions.apply(event)
     }
     homeSessions.refresh(event.type)
     if (eventType === "integration.connection.updated") void refreshProviders()
@@ -584,21 +590,27 @@ export function createServerSyncContextInner(serverSDK: ServerSDK) {
         lastConnectedQueueAt = Date.now()
         for (const directory of Object.keys(children.children)) {
           if (!children.active(directory)) continue
-          queue.push(directory)
+          // #1539: a remote server.connected/global.disposed must not trigger
+          // local directory re-bootstraps.
+          if (!isRemote) queue.push(directory)
         }
       }
       return
     }
 
-    if (event.current?.type === "session.moved") {
-      const info = session.get(event.current.data.sessionID)
-      if (info) indexSession(info)
+    // #1539: indexSession inserts synthetic session.created events into the
+    // directory store — skip for remote events.
+    if (!isRemote) {
+      if (event.current?.type === "session.moved") {
+        const info = session.get(event.current.data.sessionID)
+        if (info) indexSession(info)
+      }
+      if (event.current?.type === "session.forked")
+        void session
+          .resolve(event.current.data.sessionID, { force: true })
+          .then(indexSession)
+          .catch(() => {})
     }
-    if (event.current?.type === "session.forked")
-      void session
-        .resolve(event.current.data.sessionID, { force: true })
-        .then(indexSession)
-        .catch(() => {})
 
     const existing = children.children[key]
     if (!existing) return
@@ -610,10 +622,16 @@ export function createServerSyncContextInner(serverSDK: ServerSDK) {
       eventType === "command.updated" ||
       eventType === "config.updated" ||
       eventType === "agent.updated"
-    )
-      queue.push(key)
+    ) {
+      // #1539: queue.push triggers directory re-fetches that would pull remote
+      // sessions into the local store.
+      if (!isRemote) queue.push(key)
+    }
     if (eventType === "mcp.status.changed") void queryClient.invalidateQueries(queryOptionsApi.mcp(key))
     if (eventType === "mcp.resources.changed") void queryClient.invalidateQueries(queryOptionsApi.mcpResources(key))
+    // #1539: applyDirectoryEvent is the primary contamination point — remote
+    // events must not insert into or update the directory-scoped store.session.
+    if (isRemote) return
     const [store, setStore] = existing
     applyDirectoryEvent({
       event,