From f3fafacf93765944cc221be3349febacf46e4f5c Mon Sep 17 00:00:00 2001
From: Leo Li <cheerleaderleo@outlook.com>
Date: Sun, 1 Nov 2026 13:57:33 +0000
Subject: [PATCH] Remote chats: model, mode and option picks reach the daemon
 in the order they were made

RemoteAcpmuxWire ran each pick in its own Task, so three picks sent together reached the owning
machine's daemon in any order: RemoteAcpmuxSettingsTests.modelModeAndOptionPicksGoToThisChat
failed 2 of 6 tip runs with "config effort=high" before "mode acceptEdits". Order matters to a
person too: a model switch can reset the options picked after it. Each pick now waits for the one
sent before it; other page requests still run at once.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Agent-Session: https://cmux.com/deeplink/agent?id=aid-9124da39adbff74677d9
---
 .../CmuxNextAgentPane/RemoteAcpmuxWire.swift  | 41 ++++++++++++++-----
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/Packages/macOS/CmuxNext/Sources/CmuxNextAgentPane/RemoteAcpmuxWire.swift b/Packages/macOS/CmuxNext/Sources/CmuxNextAgentPane/RemoteAcpmuxWire.swift
index 4d6c4bd4c636..b1b561322642 100644
--- a/Packages/macOS/CmuxNext/Sources/CmuxNextAgentPane/RemoteAcpmuxWire.swift
+++ b/Packages/macOS/CmuxNext/Sources/CmuxNextAgentPane/RemoteAcpmuxWire.swift
@@ -69,6 +69,9 @@ public nonisolated final class RemoteAcpmuxWire: AcpmuxPaneWire {
         var session: String?
         /// A `session/new` is starting the chat (one at a time).
         var starting = false
+        /// The latest model, mode or option pick: the next one waits for it, so picks reach the
+        /// daemon in the order the person made them (a model switch can reset its options).
+        var lastPick: Task<Void, Never>?
     }
 
     private static let logger = Logger(subsystem: "com.cmuxterm.app.next", category: "agent-pane.remote")
@@ -221,7 +224,7 @@ public nonisolated final class RemoteAcpmuxWire: AcpmuxPaneWire {
             // and acpmux's answer goes back as it is (a config option's names the whole list).
             guard !isReadOnly else { return refuseReadOnly(id, method) }
             guard names(params["sessionId"]), let setting = Self.setting(method, params) else { return refuse(id, method) }
-            run(id) { client in
+            run(id, afterEarlierPicks: true) { client in
                 switch setting {
                 case .model(let model): return try await client.setModel(model)
                 case .mode(let mode): return try await client.setMode(mode)
@@ -455,24 +458,40 @@ public nonisolated final class RemoteAcpmuxWire: AcpmuxPaneWire {
         return parts.joined(separator: "\n\n")
     }
 
-    private func run(_ id: String?, _ work: @escaping @Sendable (any AgentSessionRemoteClient) async throws -> Data) {
+    /// With `afterEarlierPicks`, the call starts once the pick sent before it has answered.
+    private func run(_ id: String?, afterEarlierPicks: Bool = false,
+                     _ work: @escaping @Sendable (any AgentSessionRemoteClient) async throws -> Data) {
         // A new chat before its first send has no attachment: nothing to page, cancel or detach.
         guard let client = state.withLock({ $0.client }) else {
             return reply(id, [:])
         }
-        // task-owner: one daemon call per page request; its reply ends it
-        Task { [weak self] in
-            do {
-                let result = try await work(client)
-                self?.emit(id.map { #"{"jsonrpc":"2.0","id":\#($0),"result":"# + String(decoding: result, as: UTF8.self) + "}" })
-            } catch let error as AgentSessionRemoteError {
-                self?.fail(id, code: error.code, message: error.message)
-            } catch {
-                self?.fail(id, code: Self.unsupported, message: String(describing: error))
+        guard afterEarlierPicks else {
+            // task-owner: one daemon call per page request; its reply ends it
+            Task { [weak self] in await self?.answer(id, client, work) }
+            return
+        }
+        state.withLock { state in
+            let earlier = state.lastPick
+            // task-owner: one daemon call per pick, after the one before it; its reply ends it
+            state.lastPick = Task { [weak self] in
+                await earlier?.value
+                await self?.answer(id, client, work)
             }
         }
     }
 
+    private func answer(_ id: String?, _ client: any AgentSessionRemoteClient,
+                        _ work: @Sendable (any AgentSessionRemoteClient) async throws -> Data) async {
+        do {
+            let result = try await work(client)
+            emit(id.map { #"{"jsonrpc":"2.0","id":\#($0),"result":"# + String(decoding: result, as: UTF8.self) + "}" })
+        } catch let error as AgentSessionRemoteError {
+            fail(id, code: error.code, message: error.message)
+        } catch {
+            fail(id, code: Self.unsupported, message: String(describing: error))
+        }
+    }
+
     private func refuse(_ id: String?, _ method: String) {
         fail(id, code: Self.unsupported, message: "\(method) is not available for a chat on another machine")
     }