diff --git a/packages/server/src/server/agent/agent-projections.test.ts b/packages/server/src/server/agent/agent-projections.test.ts
index c516b84f46..13c4373bc0 100644
--- a/packages/server/src/server/agent/agent-projections.test.ts
+++ b/packages/server/src/server/agent/agent-projections.test.ts
@@ -94,6 +94,7 @@ function createManagedAgent(overrides: ManagedAgentOverrides = {}): ManagedAgent
     historyPrimed: true,
     lastUserMessageAt: now,
     attention: { requiresAttention: false },
+    dismissedProviderSubagentIds: new Set(),
   };
 
   return {
@@ -134,6 +135,7 @@ describe("toStoredAgentRecord", () => {
   it("captures lifecycle metadata, config, and persistence", () => {
     const agent = createManagedAgent({
       currentModeId: "focus",
+      dismissedProviderSubagentIds: new Set(["native-child"]),
       persistence: {
         provider: "claude",
         sessionId: "persist-2",
@@ -155,6 +157,7 @@ describe("toStoredAgentRecord", () => {
     expect(record.updatedAt).toBe(agent.updatedAt.toISOString());
     expect(record.lastActivityAt).toBe(agent.updatedAt.toISOString());
     expect(record.lastUserMessageAt).toBe(agent.lastUserMessageAt?.toISOString());
+    expect(record.dismissedProviderSubagentIds).toEqual(["native-child"]);
     expect(record.persistence).toEqual({
       provider: "claude",
       sessionId: "persist-2",
diff --git a/packages/server/src/server/agent/agent-storage.test.ts b/packages/server/src/server/agent/agent-storage.test.ts
index a9b1ab762f..b02201574b 100644
--- a/packages/server/src/server/agent/agent-storage.test.ts
+++ b/packages/server/src/server/agent/agent-storage.test.ts
@@ -126,6 +126,7 @@ function createManagedAgent(overrides: ManagedAgentOverrides = {}): ManagedAgent
     lastUserMessageAt: overrides.lastUserMessageAt ?? core.now,
     lastUsage: overrides.lastUsage,
     lastError: overrides.lastError,
+    dismissedProviderSubagentIds: overrides.dismissedProviderSubagentIds ?? new Set(),
   };
 }
 
diff --git a/packages/server/src/server/agent/providers/codex/tool-call-mapper.test.ts b/packages/server/src/server/agent/providers/codex/tool-call-mapper.test.ts
index bf68a7b572..4959ddf49e 100644
--- a/packages/server/src/server/agent/providers/codex/tool-call-mapper.test.ts
+++ b/packages/server/src/server/agent/providers/codex/tool-call-mapper.test.ts
@@ -267,6 +267,24 @@ describe("codex tool-call mapper", () => {
     });
   });
 
+  it("uses only the final segment of a subAgentActivity path outside the root namespace", () => {
+    const item = mapCodexToolCallFromThreadItem({
+      type: "subAgentActivity",
+      id: "activity-external-path",
+      kind: "started",
+      agentThreadId: "child-thread-external-path",
+      agentPath: "/tmp/native/investigator",
+    });
+
+    expect(item).toMatchObject({
+      detail: {
+        type: "sub_agent",
+        subAgentType: "investigator",
+        description: "/tmp/native/investigator",
+      },
+    });
+  });
+
   it("does not fail a collabAgentToolCall from child error state alone", () => {
     const item = mapCodexToolCallFromThreadItem({
       type: "collabAgentToolCall",
diff --git a/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts b/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts
index 64f25323d5..f6fd593c30 100644
--- a/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts
+++ b/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts
@@ -993,7 +993,15 @@ function mapCollabAgentToolCallItem(
 function mapSubAgentActivityItem(
   item: z.infer<typeof CodexSubAgentActivityItemSchema>,
 ): ToolCallTimelineItem {
-  const nativeName = item.agentPath.replace(/^\/root(?:\/|$)/, "") || "Sub-agent";
+  let nativeName = item.agentPath;
+  if (nativeName === "/root") {
+    nativeName = "";
+  } else if (nativeName.startsWith("/root/")) {
+    nativeName = nativeName.slice("/root/".length);
+  } else if (nativeName.includes("/")) {
+    nativeName = nativeName.slice(nativeName.lastIndexOf("/") + 1);
+  }
+  nativeName ||= "Sub-agent";
   return {
     type: "tool_call",
     callId: item.id,