diff --git a/packages/core/src/wellknown.ts b/packages/core/src/wellknown.ts
index 1160a8edd455..6a130ccd5609 100644
--- a/packages/core/src/wellknown.ts
+++ b/packages/core/src/wellknown.ts
@@ -111,15 +111,25 @@ const layer = Layer.effect(
       return { origin, integrationID: Integration.ID.make(origin), manifest }
     })
 
-    const load = Effect.fn("WellKnown.load")(function* () {
-      const value = yield* kv.get(sourcesKey)
-      const origins = Schema.is(Sources)(value) ? value : []
-      const current = yield* Ref.get(cache)
+    const loadEntries = Effect.fn("WellKnown.loadEntries")(function* (origins: readonly string[], reuse: boolean) {
+      const current = Ref.getUnsafe(cache)
       const entries = yield* Effect.forEach(origins, (origin) => {
         const cached = current.get(origin)
-        if (cached) return Effect.succeed(cached)
-        return loadEntry(origin)
+        if (cached && reuse) return Effect.succeed(cached)
+        // An unreachable origin keeps its last known manifest, or is skipped when nothing is
+        // cached. One torn-down deployment must not hide every other origin's integrations.
+        return loadEntry(origin).pipe(
+          Effect.catch((error) =>
+            Effect.logWarning("failed to load wellknown manifest", { origin, error }).pipe(Effect.as(cached)),
+          ),
+        )
       })
+      return entries.filter((entry): entry is Entry => entry !== undefined)
+    })
+
+    const load = Effect.fn("WellKnown.load")(function* () {
+      const value = yield* kv.get(sourcesKey)
+      const entries = yield* loadEntries(Schema.is(Sources)(value) ? value : [], true)
       yield* Ref.set(cache, new Map(entries.map((entry) => [entry.origin, entry])))
       return entries
     })
@@ -129,7 +139,7 @@ const layer = Layer.effect(
         const value = yield* kv.get(sourcesKey)
         const origins = Schema.is(Sources)(value) ? value : []
         if (!origins.length) return false
-        const entries = yield* Effect.forEach(origins, loadEntry)
+        const entries = yield* loadEntries(origins, false)
         const next = new Map(entries.map((entry) => [entry.origin, entry]))
         const changed = !isDeepStrictEqual(Ref.getUnsafe(cache), next)
         if (!changed) return false
diff --git a/packages/core/src/wellknown/plugin.ts b/packages/core/src/wellknown/plugin.ts
index 53f33176b532..0cfbeb3fc08f 100644
--- a/packages/core/src/wellknown/plugin.ts
+++ b/packages/core/src/wellknown/plugin.ts
@@ -10,7 +10,11 @@ export const Plugin = define({
   effect: Effect.fn(function* (ctx) {
     const bus = yield* Bus.Service
     const wellknown = yield* WellKnown.Service
-    yield* wellknown.entries().pipe(Effect.orDie)
+    // Priming the cache is best effort. Failing here would abort the plugin before it registers
+    // its transform, permanently hiding every well-known integration until the next restart.
+    yield* wellknown
+      .entries()
+      .pipe(Effect.catch((error) => Effect.logWarning("failed to load wellknown entries", { error })))
     yield* ctx.integration.transform((draft) => {
       wellknown.snapshot().forEach((entry) => {
         if (!entry.manifest.auth) return
diff --git a/packages/core/test/wellknown.test.ts b/packages/core/test/wellknown.test.ts
index 9a2e4e106776..5c4a6fb23e4d 100644
--- a/packages/core/test/wellknown.test.ts
+++ b/packages/core/test/wellknown.test.ts
@@ -117,3 +117,40 @@ serviceIt.live("refreshes changed manifests", () =>
     ({ server }) => Effect.promise(() => server.stop(true)),
   ),
 )
+
+serviceIt.live("keeps healthy origins when another is unreachable", () =>
+  Effect.acquireUseRelease(
+    Effect.sync(() =>
+      Bun.serve({
+        port: 0,
+        fetch: () => Response.json({ auth: { command: ["login"], env: "TOKEN" } }),
+      }),
+    ),
+    (server) =>
+      Effect.gen(function* () {
+        const wellknown = yield* WellKnown.Service
+        const kv = yield* KV.Service
+        // Port 1 is closed, standing in for a torn-down deployment still listed in sources.
+        yield* kv.set("wellknown:sources", ["http://127.0.0.1:1", server.url.origin])
+
+        expect((yield* wellknown.entries()).map((entry) => entry.origin)).toEqual([server.url.origin])
+        expect(wellknown.snapshot().map((entry) => entry.origin)).toEqual([server.url.origin])
+      }),
+    (server) => Effect.promise(() => server.stop(true)),
+  ),
+)
+
+serviceIt.live("keeps the last manifest when an origin becomes unreachable", () =>
+  Effect.gen(function* () {
+    const server = Bun.serve({ port: 0, fetch: () => Response.json({ auth: { command: ["login"], env: "TOKEN" } }) })
+    const wellknown = yield* WellKnown.Service
+    const kv = yield* KV.Service
+    yield* kv.set("wellknown:sources", [server.url.origin])
+    yield* wellknown.entries()
+    yield* Effect.promise(() => server.stop(true))
+
+    // A temporary outage must not drop the integration and its remote config mid-session.
+    expect(yield* wellknown.refresh()).toBe(false)
+    expect(wellknown.snapshot().map((entry) => entry.origin)).toEqual([server.url.origin])
+  }),
+)