fix(reply): prefer provider over surface for run channel fallback

src/auto-reply/reply/get-reply-run.media-only.test.ts

@@ -281,6 +281,37 @@ describe("runPreparedReply media-only handling", () => {
     expect(call?.followupRun.run.messageProvider).toBe("webchat");
   });
 
+  it("prefers Provider over Surface when origin channel is missing", async () => {
+    await runPreparedReply(
+      baseParams({
+        ctx: {
+          Body: "",
+          RawBody: "",
+          CommandBody: "",
+          ThreadHistoryBody: "Earlier message in this thread",
+          OriginatingChannel: undefined,
+          OriginatingTo: undefined,
+          Provider: "feishu",
+          Surface: "webchat",
+          ChatType: "group",
+        },
+        sessionCtx: {
+          Body: "",
+          BodyStripped: "",
+          ThreadHistoryBody: "Earlier message in this thread",
+          MediaPath: "/tmp/input.png",
+          Provider: "webchat",
+          ChatType: "group",
+          OriginatingChannel: undefined,
+          OriginatingTo: undefined,
+        },
+      }),
+    );
+
+    const call = vi.mocked(runReplyAgent).mock.calls[0]?.[0];
+    expect(call?.followupRun.run.messageProvider).toBe("feishu");
+  });
+
   it("passes suppressTyping through typing mode resolution", async () => {
     await runPreparedReply(
       baseParams({

src/auto-reply/reply/get-reply-run.ts

@@ -477,7 +477,10 @@ export async function runPreparedReply(
       sessionKey,
       messageProvider: resolveOriginMessageProvider({
         originatingChannel: ctx.OriginatingChannel ?? sessionCtx.OriginatingChannel,
-        provider: ctx.Surface ?? ctx.Provider ?? sessionCtx.Provider,
+        // Prefer Provider over Surface for fallback channel identity.
+        // Surface can carry relayed metadata (for example "webchat") while Provider
+        // still reflects the active channel that should own tool routing.
+        provider: ctx.Provider ?? ctx.Surface ?? sessionCtx.Provider,
       }),
       agentAccountId: sessionCtx.AccountId,
       groupId: resolveGroupSessionKey(sessionCtx)?.id ?? undefined,