diff --git a/src/agents/tools/sessions-helpers.ts b/src/agents/tools/sessions-helpers.ts
index 63c87e16884..06dea0b279e 100644
--- a/src/agents/tools/sessions-helpers.ts
+++ b/src/agents/tools/sessions-helpers.ts
@@ -52,6 +52,9 @@ export type SessionListRow = {
   key: string;
   kind: SessionKind;
   channel: string;
+  origin?: {
+    provider?: string;
+  };
   spawnedBy?: string;
   label?: string;
   displayName?: string;
diff --git a/src/agents/tools/sessions-list-tool.ts b/src/agents/tools/sessions-list-tool.ts
index cea07e09f1e..179ad9f6c60 100644
--- a/src/agents/tools/sessions-list-tool.ts
+++ b/src/agents/tools/sessions-list-tool.ts
@@ -137,6 +137,12 @@ export function createSessionsListTool(opts?: {
         });
 
         const entryChannel = typeof entry.channel === "string" ? entry.channel : undefined;
+        const entryOrigin =
+          entry.origin && typeof entry.origin === "object"
+            ? (entry.origin as Record<string, unknown>)
+            : undefined;
+        const originChannel =
+          typeof entryOrigin?.provider === "string" ? entryOrigin.provider : undefined;
         const deliveryContext =
           entry.deliveryContext && typeof entry.deliveryContext === "object"
             ? (entry.deliveryContext as Record<string, unknown>)
@@ -155,7 +161,7 @@ export function createSessionsListTool(opts?: {
         const derivedChannel = deriveChannel({
           key,
           kind,
-          channel: entryChannel,
+          channel: entryChannel ?? originChannel,
           lastChannel,
         });
 
diff --git a/src/agents/tools/sessions.test.ts b/src/agents/tools/sessions.test.ts
index 877b00eae6f..f324d43b775 100644
--- a/src/agents/tools/sessions.test.ts
+++ b/src/agents/tools/sessions.test.ts
@@ -432,6 +432,38 @@ describe("sessions_list transcriptPath resolution", () => {
   });
 });
 
+describe("sessions_list channel derivation", () => {
+  beforeEach(() => {
+    callGatewayMock.mockClear();
+    loadConfigMock.mockReturnValue({
+      session: { scope: "per-sender", mainKey: "main" },
+      tools: {
+        agentToAgent: { enabled: true },
+        sessions: { visibility: "all" },
+      },
+    });
+  });
+
+  it("falls back to origin.provider when the legacy top-level channel field is missing", async () => {
+    callGatewayMock.mockResolvedValueOnce({
+      path: "/tmp/sessions.json",
+      sessions: [
+        {
+          key: "agent:main:discord:group:ops",
+          kind: "group",
+          origin: { provider: "discord" },
+        },
+      ],
+    });
+
+    const result = await executeMainSessionsList();
+
+    expect(result.details).toMatchObject({
+      sessions: [{ key: "agent:main:discord:group:ops", channel: "discord" }],
+    });
+  });
+});
+
 describe("sessions_send gating", () => {
   beforeEach(() => {
     callGatewayMock.mockClear();