diff --git a/desktop/src/features/agents/lib/agentAutocompleteEligibility.test.mjs b/desktop/src/features/agents/lib/agentAutocompleteEligibility.test.mjs
index 4e02b7bd681..ae1290dd9fb 100644
--- a/desktop/src/features/agents/lib/agentAutocompleteEligibility.test.mjs
+++ b/desktop/src/features/agents/lib/agentAutocompleteEligibility.test.mjs
@@ -5,7 +5,7 @@ import {
   coalesceAgentAutocompleteCandidates,
   getMentionableAgentPubkeys,
   getSharedChannelIds,
-  isAgentIdentityInManagedList,
+  isKnownLiveAgentIdentity,
   relayAgentIsSharedWithUser,
   shouldHideAgentFromMentions,
 } from "./agentAutocompleteEligibility.ts";
@@ -136,27 +136,44 @@ test("getMentionableAgentPubkeys: keeps managed agents and shared relay agents",
   assert.deepEqual(result, new Set([PUB_A, PUB_B, PUB_C]));
 });
 
-test("isAgentIdentityInManagedList: keeps people and only current managed agent identities", () => {
+test("isKnownLiveAgentIdentity: keeps people, managed agents, and directory-listed foreign agents", () => {
   const managedAgentPubkeys = new Set([PUB_A]);
+  const directoryAgentPubkeys = new Set([PUB_C]);
 
+  // People always pass.
   assert.equal(
-    isAgentIdentityInManagedList(
+    isKnownLiveAgentIdentity(
       { isAgent: false, pubkey: PUB_B },
       managedAgentPubkeys,
+      directoryAgentPubkeys,
     ),
     true,
   );
+  // Locally managed agent passes (pubkey normalization included).
   assert.equal(
-    isAgentIdentityInManagedList(
+    isKnownLiveAgentIdentity(
       { isAgent: true, pubkey: PUB_A.toUpperCase() },
       managedAgentPubkeys,
+      directoryAgentPubkeys,
     ),
     true,
   );
+  // Foreign agent with a live relay directory entry (kind:10100) passes —
+  // e.g. an agent managed by another desktop that is a channel member.
   assert.equal(
-    isAgentIdentityInManagedList(
+    isKnownLiveAgentIdentity(
+      { isAgent: true, pubkey: PUB_C },
+      managedAgentPubkeys,
+      directoryAgentPubkeys,
+    ),
+    true,
+  );
+  // Stale agent identity — neither managed nor in the directory — is dropped.
+  assert.equal(
+    isKnownLiveAgentIdentity(
       { isAgent: true, pubkey: PUB_B },
       managedAgentPubkeys,
+      directoryAgentPubkeys,
     ),
     false,
   );
diff --git a/desktop/src/features/agents/lib/agentAutocompleteEligibility.ts b/desktop/src/features/agents/lib/agentAutocompleteEligibility.ts
index e4afe7fea4a..c7a452c1120 100644
--- a/desktop/src/features/agents/lib/agentAutocompleteEligibility.ts
+++ b/desktop/src/features/agents/lib/agentAutocompleteEligibility.ts
@@ -54,13 +54,26 @@ export function getMentionableAgentPubkeys({
   return pubkeys;
 }
 
-export function isAgentIdentityInManagedList(
+/**
+ * A concrete agent identity is kept in autocomplete only when there is live
+ * evidence for it: the current user's managed Agents list, or a relay agent
+ * directory entry (kind:10100) published by its owning desktop. Stale
+ * identities — old p-tag/channel-member keys with no directory entry — are
+ * dropped. People are always kept. Whether a surviving foreign agent is
+ * ultimately shown is decided by `shouldHideAgentFromMentions`, which hides
+ * explicitly non-invocable ones.
+ */
+export function isKnownLiveAgentIdentity(
   candidate: { isAgent?: boolean; pubkey: string },
   managedAgentPubkeys: ReadonlySet<string>,
+  directoryAgentPubkeys: ReadonlySet<string>,
 ) {
+  if (candidate.isAgent !== true) {
+    return true;
+  }
+  const normalized = normalizePubkey(candidate.pubkey);
   return (
-    candidate.isAgent !== true ||
-    managedAgentPubkeys.has(normalizePubkey(candidate.pubkey))
+    managedAgentPubkeys.has(normalized) || directoryAgentPubkeys.has(normalized)
   );
 }
 
diff --git a/desktop/src/features/channels/ui/MembersSidebar.tsx b/desktop/src/features/channels/ui/MembersSidebar.tsx
index c6349546a23..68aeff65c98 100644
--- a/desktop/src/features/channels/ui/MembersSidebar.tsx
+++ b/desktop/src/features/channels/ui/MembersSidebar.tsx
@@ -9,7 +9,7 @@ import {
 import { attachManagedAgentToChannel } from "@/features/agents/channelAgents";
 import {
   coalesceAgentAutocompleteCandidates,
-  isAgentIdentityInManagedList,
+  isKnownLiveAgentIdentity,
 } from "@/features/agents/lib/agentAutocompleteEligibility";
 import { useIsArchivedPredicate } from "@/features/identity-archive/hooks";
 import { useClassifiedMembers } from "@/features/channels/lib/useClassifiedMembers";
@@ -272,6 +272,11 @@ export function MembersSidebar({
         .filter((label): label is string => Boolean(label)),
     );
     const managedAgentPubkeys = new Set(managedAgentsByPubkey.keys());
+    const directoryAgentPubkeys = new Set(
+      (relayAgentsQuery.data ?? []).map((agent) =>
+        normalizePubkey(agent.pubkey),
+      ),
+    );
 
     const addCandidate = (candidate: AddMemberSearchCandidate) => {
       const pubkey = normalizePubkey(candidate.pubkey);
@@ -282,7 +287,11 @@ export function MembersSidebar({
           )) ||
         memberPubkeys.has(pubkey) ||
         isArchivedDiscovery(pubkey) ||
-        !isAgentIdentityInManagedList(candidate, managedAgentPubkeys)
+        !isKnownLiveAgentIdentity(
+          candidate,
+          managedAgentPubkeys,
+          directoryAgentPubkeys,
+        )
       ) {
         return;
       }
diff --git a/desktop/src/features/messages/lib/useMentions.ts b/desktop/src/features/messages/lib/useMentions.ts
index 0c73b753390..ec98b7f378a 100644
--- a/desktop/src/features/messages/lib/useMentions.ts
+++ b/desktop/src/features/messages/lib/useMentions.ts
@@ -16,7 +16,7 @@ import {
   coalesceAutocompleteCandidatesByKey,
   getMentionableAgentPubkeys,
   getSharedChannelIds,
-  isAgentIdentityInManagedList,
+  isKnownLiveAgentIdentity,
   shouldHideAgentFromMentions,
 } from "@/features/agents/lib/agentAutocompleteEligibility";
 import {
@@ -246,7 +246,13 @@ export function useMentions(
       if (isArchivedDiscovery(pubkey)) {
         return;
       }
-      if (!isAgentIdentityInManagedList(candidate, managedAgentPubkeys)) {
+      if (
+        !isKnownLiveAgentIdentity(
+          candidate,
+          managedAgentPubkeys,
+          directoryAgentPubkeys,
+        )
+      ) {
         return;
       }
       if (