Preserve ACP agent pane working directories across sessions (#744)

* Preserve host workspace cwd for ACP sessions

* Prefer source pane cwd for ACP sessions

* Separate ACP and helper working directories

* Preserve normalized cwd across helper sessions

* Add packaged agent pane cwd coverage

Author: DinahK-2SO

src/cascadia/TerminalApp/TerminalPage.cpp

@@ -22,6 +22,7 @@
 #include "../inc/AgentRegistry.h"
 #include "../inc/AgentPolicy.h"
 #include "../inc/AgentPaneBackend.h"
+#include "../inc/AgentSourceUtils.h"
 #include "../TerminalSettingsAppAdapterLib/TerminalSettings.h"
 #include "../inc/CustomModelProviderUtils.h"
 #include "AgentPaneContent.h"
@@ -1599,11 +1600,9 @@ namespace winrt::TerminalApp::implementation
         }
         if (activeCwd.empty())
         {
-            wchar_t homePath[MAX_PATH];
-            if (GetEnvironmentVariableW(L"USERPROFILE", homePath, MAX_PATH) > 0)
-            {
-                activeCwd = winrt::hstring{ homePath };
-            }
+            activeCwd = winrt::hstring{
+                ::Microsoft::Terminal::AgentSource::ReadEnvironmentVariable(L"USERPROFILE")
+            };
         }
         if (!activeCwd.empty())
         {
@@ -3114,9 +3113,10 @@ namespace winrt::TerminalApp::implementation
             }
         }
 
-        // Resolve cwd. Priority matches the legacy spawn:
-        //   a) VirtualWorkingDirectory (CLI-remoted commands like `wt agent`)
-        //   b) Active pane CWD of THIS tab (from shell integration / OSC 9;9)
+        // Resolve the source-aware ACP cwd and the Win32 helper launch cwd separately:
+        //   a) Active pane CWD of THIS tab (pre-seeded from its starting directory,
+        //      then updated by shell integration / OSC 9;9)
+        //   b) VirtualWorkingDirectory (CLI-remoted commands like `wt agent`)
         //   c) Profile's configured starting directory
         //   d) User's home directory
         //
@@ -3127,43 +3127,46 @@ namespace winrt::TerminalApp::implementation
         // the helper would start in the wrong directory (autofix and
         // agent context would attribute to the wrong project). Reading
         // directly from `tab` resolves to whichever pane is active on
-        // this specific tab. If shell integration hasn't reported a cwd
-        // yet (common for a just-spawned background tab) we fall through
-        // to (c)/(d) below.
-        winrt::hstring startingDirectory = _WindowProperties.VirtualWorkingDirectory();
-        if (startingDirectory.empty())
-        {
-            if (const auto activeControl = tab->GetActiveTerminalControl())
-            {
-                startingDirectory = activeControl.WorkingDirectory();
-            }
-        }
-        if (startingDirectory.empty())
-        {
-            if (sourceProfile)
-            {
-                startingDirectory = sourceProfile.EvaluatedStartingDirectory();
-            }
-        }
-        if (startingDirectory.empty())
+        // this specific tab. For a WSL agent, that source cwd may be POSIX and
+        // must not become the Windows wta-helper process's starting directory.
+        // The pane cwd must also win over the window cwd for agent context: deferred
+        // pre-warm runs after startup actions restore that property to the
+        // launcher directory, which is System32 for an AUMID activation.
+        winrt::hstring paneDirectory;
+        if (const auto activeControl = tab->GetActiveTerminalControl())
+        {
+            paneDirectory = activeControl.WorkingDirectory();
+        }
+        const auto windowDirectory = _WindowProperties.VirtualWorkingDirectory();
+        winrt::hstring profileDirectory;
+        if (sourceProfile)
         {
-            wchar_t homePath[MAX_PATH];
-            if (GetEnvironmentVariableW(L"USERPROFILE", homePath, MAX_PATH) > 0)
-            {
-                startingDirectory = winrt::hstring{ homePath };
-            }
+            profileDirectory = sourceProfile.EvaluatedStartingDirectory();
         }
-        if (effectiveAgentSource == L"wsl" && !startingDirectory.empty())
+        const winrt::hstring homeDirectory{
+            ::Microsoft::Terminal::AgentSource::ReadEnvironmentVariable(L"USERPROFILE")
+        };
+        const auto resolvedWorkingDirectories = ::Microsoft::Terminal::AgentSource::ResolveAgentAndHelperWorkingDirectories(
+            effectiveAgentSource == L"wsl",
+            std::wstring_view{ paneDirectory },
+            std::wstring_view{ windowDirectory },
+            std::wstring_view{ profileDirectory },
+            std::wstring_view{ homeDirectory },
+            [](const std::wstring_view candidate) {
+                const std::wstring path{ candidate };
+                return Utils::IsValidDirectory(path.c_str());
+            });
+        if (!resolvedWorkingDirectories.agent.empty())
         {
-            appendHelperFlagValue(L"--agent-source-cwd", startingDirectory);
+            appendHelperFlagValue(L"--agent-source-cwd", resolvedWorkingDirectories.agent);
         }
 
         NewTerminalArgs args;
         args.Commandline(winrt::hstring{ helperCmd });
         args.Profile(globals.AiCoordinatorProfile());
-        if (!startingDirectory.empty())
+        if (!resolvedWorkingDirectories.helper.empty())
         {
-            args.StartingDirectory(startingDirectory);
+            args.StartingDirectory(winrt::hstring{ resolvedWorkingDirectories.helper });
         }
 
         auto rawPane = _MakeTerminalPane(args, nullptr, nullptr);

src/cascadia/inc/AgentSourceUtils.h

@@ -0,0 +1,65 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#include <wil/win32_helpers.h>
+
+#include <string>
+#include <string_view>
+#include <utility>
+
+namespace Microsoft::Terminal::AgentSource
+{
+    struct ResolvedWorkingDirectories
+    {
+        std::wstring agent;
+        std::wstring helper;
+    };
+
+    inline std::wstring ReadEnvironmentVariable(const wchar_t* name)
+    {
+        return wil::TryGetEnvironmentVariableW<std::wstring>(name);
+    }
+
+    inline std::wstring ResolveCwd(
+        const std::wstring_view paneCwd,
+        const std::wstring_view windowCwd,
+        const std::wstring_view profileCwd,
+        const std::wstring_view homeCwd)
+    {
+        for (const auto candidate : { paneCwd, windowCwd, profileCwd, homeCwd })
+        {
+            if (!candidate.empty())
+            {
+                return std::wstring{ candidate };
+            }
+        }
+        return {};
+    }
+
+    template<typename IsWindowsDirectory>
+    inline ResolvedWorkingDirectories ResolveAgentAndHelperWorkingDirectories(
+        const bool agentRunsInWsl,
+        const std::wstring_view paneCwd,
+        const std::wstring_view windowCwd,
+        const std::wstring_view profileCwd,
+        const std::wstring_view homeCwd,
+        IsWindowsDirectory&& isWindowsDirectory)
+    {
+        std::wstring helperCwd;
+        for (const auto candidate : { paneCwd, windowCwd, profileCwd, homeCwd })
+        {
+            if (!candidate.empty() && isWindowsDirectory(candidate))
+            {
+                helperCwd = candidate;
+                break;
+            }
+        }
+
+        auto agentCwd = agentRunsInWsl ?
+                            ResolveCwd(paneCwd, windowCwd, profileCwd, homeCwd) :
+                            helperCwd;
+        return { std::move(agentCwd), std::move(helperCwd) };
+    }
+}

src/cascadia/ut_app/AgentSourceUtilsTests.cpp

@@ -0,0 +1,99 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "precomp.h"
+
+#include "../inc/AgentSourceUtils.h"
+
+using namespace WEX::TestExecution;
+
+namespace TerminalAppUnitTests
+{
+    class AgentSourceUtilsTests
+    {
+        TEST_CLASS(AgentSourceUtilsTests);
+
+        TEST_METHOD(ReadEnvironmentVariableSupportsLongValues);
+        TEST_METHOD(PrefersPaneCwdOverWindowLaunchCwd);
+        TEST_METHOD(SeparatesAgentCwdFromHelperLaunchCwd);
+    };
+
+    void AgentSourceUtilsTests::ReadEnvironmentVariableSupportsLongValues()
+    {
+        constexpr auto name = L"WT_AGENT_SOURCE_UTILS_LONG_ENV";
+        SetLastError(ERROR_SUCCESS);
+        const auto priorLength = GetEnvironmentVariableW(name, nullptr, 0);
+        const auto priorMissing = priorLength == 0 && GetLastError() == ERROR_ENVVAR_NOT_FOUND;
+        const auto priorValue = priorMissing ? std::wstring{} : Microsoft::Terminal::AgentSource::ReadEnvironmentVariable(name);
+        const std::wstring expected(MAX_PATH + 32, L'x');
+        VERIFY_WIN32_BOOL_SUCCEEDED(SetEnvironmentVariableW(name, expected.c_str()));
+        const auto cleanup = wil::scope_exit([=]() {
+            VERIFY_WIN32_BOOL_SUCCEEDED(SetEnvironmentVariableW(name, priorMissing ? nullptr : priorValue.c_str()));
+        });
+
+        VERIFY_ARE_EQUAL(expected, Microsoft::Terminal::AgentSource::ReadEnvironmentVariable(name));
+    }
+
+    void AgentSourceUtilsTests::PrefersPaneCwdOverWindowLaunchCwd()
+    {
+        namespace AgentSource = Microsoft::Terminal::AgentSource;
+        VERIFY_ARE_EQUAL(
+            std::wstring{ L"C:\\work" },
+            AgentSource::ResolveCwd(
+                L"C:\\work",
+                L"C:\\Windows\\System32",
+                L"C:\\profile",
+                L"C:\\Users\\user"));
+        VERIFY_ARE_EQUAL(
+            std::wstring{ L"C:\\window" },
+            AgentSource::ResolveCwd({}, L"C:\\window", L"C:\\profile", L"C:\\Users\\user"));
+        VERIFY_ARE_EQUAL(
+            std::wstring{ L"C:\\profile" },
+            AgentSource::ResolveCwd({}, {}, L"C:\\profile", L"C:\\Users\\user"));
+        VERIFY_ARE_EQUAL(
+            std::wstring{ L"C:\\Users\\user" },
+            AgentSource::ResolveCwd({}, {}, {}, L"C:\\Users\\user"));
+        VERIFY_ARE_EQUAL(std::wstring{}, AgentSource::ResolveCwd({}, {}, {}, {}));
+    }
+
+    void AgentSourceUtilsTests::SeparatesAgentCwdFromHelperLaunchCwd()
+    {
+        namespace AgentSource = Microsoft::Terminal::AgentSource;
+        const auto isWindowsDirectory = [](const std::wstring_view candidate) {
+            return candidate == L"C:\\window" ||
+                   candidate == L"C:\\profile" ||
+                   candidate == L"C:\\Users\\user";
+        };
+
+        const auto wsl = AgentSource::ResolveAgentAndHelperWorkingDirectories(
+            true,
+            L"/home/user/project",
+            L"C:\\window",
+            L"C:\\profile",
+            L"C:\\Users\\user",
+            isWindowsDirectory);
+        VERIFY_ARE_EQUAL(std::wstring{ L"/home/user/project" }, wsl.agent);
+        VERIFY_ARE_EQUAL(std::wstring{ L"C:\\window" }, wsl.helper);
+
+        const auto host = AgentSource::ResolveAgentAndHelperWorkingDirectories(
+            false,
+            L"/home/user/project",
+            L"C:\\window",
+            L"C:\\profile",
+            L"C:\\Users\\user",
+            isWindowsDirectory);
+        VERIFY_ARE_EQUAL(std::wstring{ L"C:\\window" }, host.agent);
+        VERIFY_ARE_EQUAL(std::wstring{ L"C:\\window" }, host.helper);
+
+        const auto noWindowsDirectory = [](std::wstring_view) { return false; };
+        const auto wslWithoutHelperCwd = AgentSource::ResolveAgentAndHelperWorkingDirectories(
+            true, L"/home/user/project", {}, {}, {}, noWindowsDirectory);
+        VERIFY_ARE_EQUAL(std::wstring{ L"/home/user/project" }, wslWithoutHelperCwd.agent);
+        VERIFY_ARE_EQUAL(std::wstring{}, wslWithoutHelperCwd.helper);
+
+        const auto hostWithoutWindowsCwd = AgentSource::ResolveAgentAndHelperWorkingDirectories(
+            false, L"/home/user/project", {}, {}, {}, noWindowsDirectory);
+        VERIFY_ARE_EQUAL(std::wstring{}, hostWithoutWindowsCwd.agent);
+        VERIFY_ARE_EQUAL(std::wstring{}, hostWithoutWindowsCwd.helper);
+    }
+}

src/cascadia/ut_app/TerminalApp.UnitTests.vcxproj

@@ -25,6 +25,7 @@
     <ClCompile Include="FzfTests.cpp" />
     <ClCompile Include="AgentHooksStatusTests.cpp" />
     <ClCompile Include="AcpModelUtilsTests.cpp" />
+    <ClCompile Include="AgentSourceUtilsTests.cpp" />
     <ClCompile Include="AgentUsageTests.cpp" />
     <ClCompile Include="BoundedDispatchQueueTests.cpp" />
     <ClCompile Include="CustomAgentIdTests.cpp" />

test/e2e/README.md

@@ -34,6 +34,7 @@ authenticated ACP agents. Current status (run on the Store package):
 | `Feature.CommandResolution.Tests.ps1` | PR #418: packaged WTA resolves PowerShell profile-only aliases to their real targets | 1 |
 | `Feature.SessionList.Tests.ps1` | session view (button + `/sessions` slash), session states, view switching (incl. draft-preservation), focus/restore | 13 (+1 skip) |
 | `Feature.NonAsciiCwd.Tests.ps1` | issue #641: a non-ASCII starting directory survives `wtcli` argv → COM → `CreateProcessW`, so the resume launch path connects and starts in that directory | 2 |
+| `Feature.AgentPaneCwd.Tests.ps1` | agent-pane source workspace reaches ACP `session/new` and remains stable across `/new` without a model prompt | 1 |
 | `Feature.AgentRestart.Tests.ps1` | agent restart after a settings change (/restart reconnects and answers) | 1 |
 | `Feature.ShellIntegration.Tests.ps1` | §3 shell-integration OSC 133 marks (success/failure, ParserError dedup, handled errors, WinPS 5.1 errors) + non-integrated cmd.exe safety | 6 |
 | `Feature.BashPromptIntegration.Tests.ps1` | PR #468: Bash `PROMPT_COMMAND` PS1 rewrites preserve D/A/B boundaries; non-IT hosts remain gated | 1 (Git Bash-gated) |

test/e2e/fixtures/Mock-AcpInteractionAgent.ps1

@@ -157,6 +157,13 @@ while ($null -ne ($line = [Console]::In.ReadLine())) {
             $server = @($request.params.mcpServers) | Select-Object -First 1
             $sessionMcpServers[$sessionId] = $server
             Write-FixtureLog -Message "session/new|$sessionId|mcp_server=$([string]$server.name)"
+            $cwdJson = if ($null -eq $request.params.cwd) {
+                'null'
+            }
+            else {
+                ConvertTo-Json -InputObject ([string]$request.params.cwd) -Compress
+            }
+            Write-FixtureLog -Message "session/new-cwd|$sessionId|$cwdJson"
             Send-AcpMessage @{
                 jsonrpc = '2.0'
                 id = $request.id