diff --git a/doc/release-check-list.md b/doc/release-check-list.md
index 8c2269f92..3ea1504b7 100644
--- a/doc/release-check-list.md
+++ b/doc/release-check-list.md
@@ -136,6 +136,7 @@ Net effect: UT shrinks the manual matrix to "did the wiring and UI connect", not
 - [ ] `C055` `[E2E]` **Stash preserves chat:** Hiding and restoring the pane preserves helper process, connection state, and chat history.
 - [ ] `C056` `[E2E]` **Tab close cleans up:** Closing the owning tab physically closes its ACP session, cleans up the helper, and does not leave a broken pane.
 - [ ] `C247` `[new]` `[E2E]` **Closing a tab mid-turn leaves sibling agent tabs working:** When one tab closes with a prompt in flight, only its ACP session is closed; the shared agent CLI remains alive and another tab can continue chatting without a restart. _(#419/#425; E2E: `Feature.SharedAgentLifecycle`.)_
+- [ ] `C278` `[new]` `[E2E]` **`/new` physically closes the replaced ACP session before creating another:** Replacing a conversation releases the prior ACP session before creating its successor and does not replay the old session. _(#610; E2E: `Feature.AgentProtocolExperience`.)_
 - [ ] `C215` `[new]` `[E2E]` **Agent panes are not persisted into saved layout:** Saving and restoring a window layout does not resurrect a previously-open agent pane; restored windows come back without an unexpected agent pane. _(#360/#275.)_
 
 ### Built-in agent chat matrix
@@ -174,6 +175,8 @@ Net effect: UT shrinks the manual matrix to "did the wiring and UI connect", not
 - [ ] `C066` `[E2E]` **Keyboard navigation works:** Arrow keys, Tab completion, Ctrl combinations, and Esc behave correctly.
 - [x] `C067` `[UT✓]` `[E2E]` `[MANUAL]` **IME/non-ASCII input works:** IME and non-ASCII input are usable if the release supports localized typing. _(UT: `render_agent_input_accepts_non_ascii` types accented-Latin/Greek/CJK via the real key handler and asserts the input buffer holds them verbatim (multi-byte caret advance) + they render. E2E send path (wtcli send-keys) cannot carry non-ASCII, so the product side is UT-covered; IME composition stays MANUAL.)_
 - [ ] `C068` `[UT✓]` `[E2E]` **Streaming output renders correctly:** Agent response chunks, tool calls, plans, status lines, and literal JSON render without corruption. _(UT: `streaming_two_chunks_coalesce_in_app_chat`, `tool_call_surfaces_card_in_chat`, `tool_call_completion_updates_card_status` (in-place, no dup), `plan_surfaces_card_in_chat`, `render_chat_all_message_variants`; Assistant JSON remains ordinary chat text.)_
+- [ ] `C279` `[new]` `[UT✓]` `[E2E]` **ACP tool details and transcript order survive the real process boundary:** Execute commands and output, plans, and trailing prose retain ACP arrival order through the stdio agent, master, Helper, and rendered pane. _(#601/#611/#612; E2E: `Feature.AgentProtocolExperience`.)_
+- [ ] `C280` `[new]` `[UT✓]` `[E2E]` **Clarification modal returns the selected answer to the requesting ACP session:** A blocking agent question renders its choices and returns the exact selected answer and index to the owning ACP session. _(#606; E2E: `Feature.AgentProtocolExperience`.)_
 - [x] `C069` `[UT✓]` `[E2E]` **Permission UI works:** When the agent requests a command/tool permission, the user can allow or reject it. _(UT: `permission_allow_round_trips_to_agent`, `permission_reject_round_trips_to_agent`, `permission_quick_allow/reject_key_round_trips_to_agent`, `render_permission_card_shows_options`, `render_permission_compact_shows_hint`; the `y`/`n` quick-key case-match bug was fixed here.)_
 - [ ] `C070` `[E2E]` **Insert into pane works:** A validated Direct Helper Proposal can be inserted into the target terminal pane without running.
 - [ ] `C253` `[new]` `[E2E]` **Insert returns keyboard focus to the target shell pane:** After Insert delivers a command without running it, normal window keyboard input continues in that target pane. _(#533; E2E: `Feature.AgentProposalFocus`.)_
@@ -190,6 +193,9 @@ Net effect: UT shrinks the manual matrix to "did the wiring and UI connect", not
 - [x] `C078` `[UT✓]` **`/stop` works:** Stops/cancels an in-progress turn.
 - [x] `C079` `[UT✓]` **`/sessions` works:** Switches to session-management view. _(UT: `slash_sessions_opens_agents_view`.)_
 - [ ] `C080` `[UT✓]` `[E2E]` **`/model` works:** Opens/selects model where supported; unsupported agents fail gracefully. _(UT: `slash_model_*`; picker render covered by `render_model_picker_lists_models`, full UI flow still E2E.)_
+- [ ] `C281` `[new]` `[UT✓]` `[E2E]` **Slash command search matches substrings and ranks the match:** Typing a middle substring filters the command popup and selects the matching command. _(#615; E2E: `Feature.AgentPopup`.)_
+- [ ] `C282` `[new]` `[UT✓]` `[E2E]` **ACP session config picker preserves order and hot-applies a selection:** `/config` renders Agent-provided options in order, sends the selected value to the live ACP session, and reflects its update without restarting. _(#616; E2E: `Feature.AgentProtocolExperience`.)_
+- [ ] `C283` `[new]` `[UT✓]` `[E2E]` **Agent pane title reflects the confirmed active model:** After ACP confirms the session model, the XAML agent-pane title displays that model rather than stale configured state. _(#634; E2E: `Feature.AgentProtocolExperience`.)_
 - [ ] `C255` `[new]` `[UT✓]` `[E2E]` **ACP model updates refresh the active picker:** A model reported by a later ACP `config_option_update` replaces stale `session/new` selection state in the active session's `/model` picker. _(UT: `session_notification_routes_model_config_update`, `model_config_update_refreshes_active_session_picker`; #538; E2E: `Feature.AgentModelSync`.)_
 - [ ] `C256` `[new]` `[UT✓]` `[E2E]` **`/model` hot-applies without restarting the agent:** Selecting another model sends the live ACP session update while preserving the current helper and agent process. _(UT: `slash_model_hot_applies_cloud_model_to_live_session`; #554; E2E: `Feature.AgentModelLifecycle`.)_
 - [ ] `C257` `[new]` `[E2E]` **Settings model changes restart and reconnect the agent:** Changing the configured cloud model rebuilds the shared agent stack, reconnects, and applies the new model to the fresh session. _(#554; E2E: `Feature.AgentModelLifecycle`.)_
@@ -197,6 +203,7 @@ Net effect: UT shrinks the manual matrix to "did the wiring and UI connect", not
 - [ ] `C260` `[new]` `[UT✓]` `[E2E]` **Leaving BYOK restarts and restores cloud models:** Clearing the custom model selection rebuilds the shared agent stack, reconnects Copilot without provider overrides, and restores its native cloud catalog. _(UT: clean cloud discovery and settings rebuild tests; #447; E2E: `Feature.ByokProvider`.)_
 - [ ] `C261` `[new]` `[UT✓]` `[E2E]` **Compact height keeps the recommendation and input usable:** At the real Agent Pane splitter minimum, the selected recommendation summary, Run/Insert actions, and editable input remain visible, and Insert still targets the owning shell without discarding its draft. _(UT: compact action-panel planning, recommendation rendering, and minimum-size tests; #580; E2E: `Feature.AgentCompactLayout`.)_
 - [ ] `C258` `[new]` `[UT✓]` `[E2E]` **Proposal MCP routing is isolated per tab:** Each ACP session receives a distinct proposal MCP server identity, and tool calls route only to that session's owning Helper even after another tab connects. _(UT: `server_configs_isolate_session_identity_and_capability`, proposal MCP capability routing tests; #560; E2E: `Feature.ProposalMcpRouting`.)_
+- [ ] `C284` `[new]` `[UT✓]` `[E2E]` **Tab-targeted terminal actions accept a direction hint across Session MCP:** A validated `open_and_send` request may retain a direction hint when its destination is a new tab. _(#599; E2E: `Feature.AgentProtocolExperience`.)_
 - [x] `C081` `[UT✓]` **Unknown slash command is safe:** Unknown `/command` does not lose user input or crash.
 - [ ] `C225` `[E2E]` **`/agent` picker works:** `/agent` opens a keyboard-operable picker containing the current installed/allowed agents, and selecting the current agent is a safe no-op.
 - [ ] `C241` `[new]` `[E2E]` **`/agent` completion selection is safe:** Enter activates the highlighted matching agent without rebuilding the pane or changing the global default when it is already selected. _(#487; E2E: `Feature.PerTabAgent`.)_
diff --git a/test/e2e/Invoke-ItE2EReport.ps1 b/test/e2e/Invoke-ItE2EReport.ps1
index 15b723a42..8203bcfa3 100644
--- a/test/e2e/Invoke-ItE2EReport.ps1
+++ b/test/e2e/Invoke-ItE2EReport.ps1
@@ -51,7 +51,13 @@ $cfg.TestResult.Enabled = $true
 $cfg.TestResult.OutputFormat = 'NUnitXml'
 $cfg.TestResult.OutputPath = (Join-Path $OutDir 'results.xml')
 
-$result = Invoke-Pester -Configuration $cfg
+$pesterOutput = @(Invoke-Pester -Configuration $cfg)
+$result = $pesterOutput |
+    Where-Object { $_.PSObject.Properties.Name -contains 'Tests' -and $_.PSObject.Properties.Name -contains 'FailedCount' } |
+    Select-Object -Last 1
+if (-not $result) {
+    throw 'Pester did not return a test result object.'
+}
 
 # ── Shared helpers ──────────────────────────────────────────────────────────
 function Get-FailureWhere($err) {
diff --git a/test/e2e/ItE2E/Public/Ui.ps1 b/test/e2e/ItE2E/Public/Ui.ps1
index a7f3b06ea..660760940 100644
--- a/test/e2e/ItE2E/Public/Ui.ps1
+++ b/test/e2e/ItE2E/Public/Ui.ps1
@@ -393,6 +393,9 @@ function Invoke-UiMouseDrag {
         [int]$HoldMs = 50
     )
     process {
+        if (-not (Set-WtWindowForeground -App $App -Attempts 3 -DelayMs 150)) {
+            throw 'No interactive desktop is available for physical mouse injection.'
+        }
         $args = @('drag', "$FromX,$FromY", "$ToX,$ToY", '--hold-ms', $HoldMs)
         if ($Right) { $args += '--right' }
         $result = Invoke-WinAppUi -App $App -UiArgs $args
diff --git a/test/e2e/README.md b/test/e2e/README.md
index 5d8412c84..0c60a5993 100644
--- a/test/e2e/README.md
+++ b/test/e2e/README.md
@@ -19,6 +19,7 @@ authenticated ACP agents. Current status (run on the Store package):
 | `Feature.FreFlow.Tests.ps1` | §0 FRE overlay click-through (Next→Save, privacy link, close-safety) | 5 |
 | `Feature.FreExecutionPolicy.Tests.ps1` | §0 FRE execution-policy verdict (deterministic via registry; **Dev**, auto-skips) | 3 (1 conditional skip) |
 | `Feature.AgentPaneInteraction.Tests.ps1` | open/hide/focus, input/rendering, slash, Copilot chat | 14 |
+| `Feature.AgentProtocolExperience.Tests.ps1` | PRs #599/#601/#606/#610/#611/#612/#616/#634: terminal actions, ACP tool/transcript rendering, clarification input, session configuration, model title, and replacement cleanup across the deployed helper/master boundary | 6 |
 | `Feature.AgentImageAttachmentEditing.Tests.ps1` | PR #536: inline image tokens move and delete atomically while preserving adjacent prompt text | 1 |
 | `Feature.AgentModelSync.Tests.ps1` | PR #538: ACP config-option updates replace stale session model state in the active picker | 1 |
 | `Feature.AgentModelLifecycle.Tests.ps1` | PR #554: `/model` hot-apply and Settings-driven model restart/reconnect lifecycle | 2 |
diff --git a/test/e2e/fixtures/Mock-AcpInteractionAgent.ps1 b/test/e2e/fixtures/Mock-AcpInteractionAgent.ps1
new file mode 100644
index 000000000..9da7c6158
--- /dev/null
+++ b/test/e2e/fixtures/Mock-AcpInteractionAgent.ps1
@@ -0,0 +1,314 @@
+param(
+    [Parameter(Mandatory)][string]$LogPath
+)
+
+$ErrorActionPreference = 'Stop'
+[Console]::OutputEncoding = [System.Text.UTF8Encoding]::new($false)
+$sessionCounter = 0
+$currentMode = 'ask'
+$sessionMcpServers = @{}
+
+function Send-AcpMessage {
+    param([Parameter(Mandatory)][hashtable]$Message)
+
+    [Console]::Out.WriteLine(($Message | ConvertTo-Json -Depth 30 -Compress))
+    [Console]::Out.Flush()
+}
+
+function Write-FixtureLog {
+    param([Parameter(Mandatory)][string]$Message)
+
+    Add-Content -LiteralPath $LogPath -Value "$PID|$Message" -Encoding utf8
+}
+
+function Get-SessionConfigOptions {
+    @(
+        @{
+            id = 'mode'
+            name = 'Mode'
+            category = 'mode'
+            type = 'select'
+            currentValue = $currentMode
+            options = @(
+                @{ value = 'ask'; name = 'Ask'; description = 'Ask before editing' }
+                @{ value = 'code'; name = 'Code'; description = 'Edit files directly' }
+            )
+        }
+        @{
+            id = 'reasoning'
+            name = 'Reasoning'
+            category = 'thought_level'
+            type = 'select'
+            currentValue = 'medium'
+            options = @(
+                @{ value = 'medium'; name = 'Medium' }
+                @{ value = 'high'; name = 'High' }
+            )
+        }
+        @{
+            id = 'model'
+            name = 'Model'
+            category = 'model'
+            type = 'select'
+            currentValue = 'fixture-model'
+            options = @(
+                @{ value = 'fixture-model'; name = 'Fixture Model' }
+            )
+        }
+    )
+}
+
+function Send-TextUpdate {
+    param(
+        [Parameter(Mandatory)][string]$SessionId,
+        [Parameter(Mandatory)][string]$Text
+    )
+
+    Send-AcpMessage @{
+        jsonrpc = '2.0'
+        method = 'session/update'
+        params = @{
+            sessionId = $SessionId
+            update = @{
+                sessionUpdate = 'agent_message_chunk'
+                content = @{ type = 'text'; text = $Text }
+            }
+        }
+    }
+}
+
+function Invoke-UserInputTool {
+    param(
+        [Parameter(Mandatory)]$Server
+    )
+
+    $headers = @{ 'mcp-protocol-version' = '2025-06-18' }
+    foreach ($header in @($Server.headers)) {
+        if ($header.name -and $header.value) {
+            $headers[[string]$header.name] = [string]$header.value
+        }
+    }
+    $body = @{
+        jsonrpc = '2.0'
+        id = 1
+        method = 'tools/call'
+        params = @{
+            name = 'request_user_input'
+            arguments = @{
+                question = 'Choose the deterministic answer'
+                choices = @('Alpha', 'Beta')
+                allow_freeform = $true
+            }
+        }
+    } | ConvertTo-Json -Depth 12 -Compress
+    Invoke-RestMethod -Method Post -Uri $Server.url -Headers $headers -ContentType 'application/json' -Body $body
+}
+
+function Invoke-TerminalActionTool {
+    param(
+        [Parameter(Mandatory)]$Server,
+        [Parameter(Mandatory)][string]$Marker
+    )
+
+    $headers = @{ 'mcp-protocol-version' = '2025-06-18' }
+    foreach ($header in @($Server.headers)) {
+        if ($header.name -and $header.value) {
+            $headers[[string]$header.name] = [string]$header.value
+        }
+    }
+    $body = @{
+        jsonrpc = '2.0'
+        id = 2
+        method = 'tools/call'
+        params = @{
+            name = 'request_terminal_actions'
+            arguments = @{
+                type = 'open_and_send'
+                title = "Direction $Marker"
+                input = "echo $Marker"
+                target = 'tab'
+                direction = 'auto'
+            }
+        }
+    } | ConvertTo-Json -Depth 12 -Compress
+    Invoke-RestMethod -Method Post -Uri $Server.url -Headers $headers -ContentType 'application/json' -Body $body
+}
+
+while ($null -ne ($line = [Console]::In.ReadLine())) {
+    $request = $line | ConvertFrom-Json
+    switch ($request.method) {
+        'initialize' {
+            Write-FixtureLog -Message 'initialize'
+            Send-AcpMessage @{
+                jsonrpc = '2.0'
+                id = $request.id
+                result = @{
+                    protocolVersion = 1
+                    agentCapabilities = @{
+                        mcpCapabilities = @{ http = $true; sse = $false }
+                        sessionCapabilities = @{ close = @{} }
+                    }
+                    agentInfo = @{
+                        name = 'Interaction Fixture'
+                        version = '1.0.0'
+                    }
+                }
+            }
+        }
+        'session/new' {
+            $sessionCounter++
+            $sessionId = "interaction-$PID-$sessionCounter"
+            $sessionMcpServers[$sessionId] = @($request.params.mcpServers) | Select-Object -First 1
+            Write-FixtureLog -Message "session/new|$sessionId"
+            Send-AcpMessage @{
+                jsonrpc = '2.0'
+                id = $request.id
+                result = @{
+                    sessionId = $sessionId
+                    configOptions = @(Get-SessionConfigOptions)
+                }
+            }
+        }
+        'session/close' {
+            Write-FixtureLog -Message "session/close|$($request.params.sessionId)"
+            Send-AcpMessage @{
+                jsonrpc = '2.0'
+                id = $request.id
+                result = @{ configOptions = @(Get-SessionConfigOptions) }
+            }
+        }
+        'session/set_config_option' {
+            $currentMode = [string]$request.params.value
+            Write-FixtureLog -Message "session/set_config_option|$($request.params.configId)|$currentMode"
+            Send-AcpMessage @{
+                jsonrpc = '2.0'
+                method = 'session/update'
+                params = @{
+                    sessionId = [string]$request.params.sessionId
+                    update = @{
+                        sessionUpdate = 'config_option_update'
+                        configOptions = @(Get-SessionConfigOptions)
+                    }
+                }
+            }
+            Send-AcpMessage @{
+                jsonrpc = '2.0'
+                id = $request.id
+                result = @{}
+            }
+        }
+        'session/prompt' {
+            $sessionId = [string]$request.params.sessionId
+            $promptText = (@($request.params.prompt) | ForEach-Object text) -join "`n"
+            Write-FixtureLog -Message "session/prompt|$sessionId|$promptText"
+
+            if ($promptText -match 'TOOL_FLOW') {
+                Send-TextUpdate -SessionId $sessionId -Text 'BEFORE_TOOL_MARKER'
+                Send-AcpMessage @{
+                    jsonrpc = '2.0'
+                    method = 'session/update'
+                    params = @{
+                        sessionId = $sessionId
+                        update = @{
+                            sessionUpdate = 'tool_call'
+                            toolCallId = 'ite2e-tool'
+                            title = 'Run integration command'
+                            kind = 'execute'
+                            status = 'in_progress'
+                            rawInput = @{
+                                command = 'echo TOOL_DETAIL_MARKER'
+                                cwd = 'C:\ite2e-work'
+                            }
+                            content = @()
+                            locations = @()
+                        }
+                    }
+                }
+                Send-AcpMessage @{
+                    jsonrpc = '2.0'
+                    method = 'session/update'
+                    params = @{
+                        sessionId = $sessionId
+                        update = @{
+                            sessionUpdate = 'tool_call_update'
+                            toolCallId = 'ite2e-tool'
+                            status = 'completed'
+                            rawOutput = @{
+                                stdout = 'TOOL_OUTPUT_MARKER'
+                                exitCode = 7
+                            }
+                        }
+                    }
+                }
+                Send-AcpMessage @{
+                    jsonrpc = '2.0'
+                    method = 'session/update'
+                    params = @{
+                        sessionId = $sessionId
+                        update = @{
+                            sessionUpdate = 'plan'
+                            entries = @(
+                                @{ content = 'PLAN_MARKER'; priority = 'medium'; status = 'completed' }
+                            )
+                        }
+                    }
+                }
+                Send-TextUpdate -SessionId $sessionId -Text 'AFTER_TOOL_MARKER'
+                Start-Sleep -Seconds 10
+                Send-AcpMessage @{
+                    jsonrpc = '2.0'
+                    id = $request.id
+                    result = @{ stopReason = 'end_turn' }
+                }
+                Write-FixtureLog -Message 'tool-flow-complete'
+            }
+            elseif ($promptText -match 'ASK_INPUT') {
+                $server = $sessionMcpServers[$sessionId]
+                if (-not $server) {
+                    throw 'session/new did not provide a Session MCP server'
+                }
+                $response = Invoke-UserInputTool -Server $server
+                $result = $response.result.structuredContent | ConvertTo-Json -Depth 20 -Compress
+                Write-FixtureLog -Message "user-input-result|$result"
+                Send-TextUpdate -SessionId $sessionId -Text "INPUT_RESULT:$result"
+                Send-AcpMessage @{
+                    jsonrpc = '2.0'
+                    id = $request.id
+                    result = @{ stopReason = 'end_turn' }
+                }
+            }
+            elseif ($promptText -match 'TAB_DIRECTION_(?<marker>[A-F0-9]+)') {
+                $server = $sessionMcpServers[$sessionId]
+                if (-not $server) {
+                    throw 'session/new did not provide a Session MCP server'
+                }
+                $marker = $Matches.marker
+                $response = Invoke-TerminalActionTool -Server $server -Marker $marker
+                $result = $response.result.structuredContent | ConvertTo-Json -Depth 20 -Compress
+                Write-FixtureLog -Message "tab-direction-result|$result"
+                Send-AcpMessage @{
+                    jsonrpc = '2.0'
+                    id = $request.id
+                    result = @{ stopReason = 'end_turn' }
+                }
+            }
+            else {
+                Send-TextUpdate -SessionId $sessionId -Text "ACK:$promptText"
+                Send-AcpMessage @{
+                    jsonrpc = '2.0'
+                    id = $request.id
+                    result = @{ stopReason = 'end_turn' }
+                }
+            }
+        }
+        default {
+            if ($null -ne $request.id) {
+                Send-AcpMessage @{
+                    jsonrpc = '2.0'
+                    id = $request.id
+                    error = @{ code = -32601; message = 'Method not found' }
+                }
+            }
+        }
+    }
+}
diff --git a/test/e2e/fixtures/Mock-AcpModelSwitchAgent.ps1 b/test/e2e/fixtures/Mock-AcpModelSwitchAgent.ps1
index b2dd104c0..4513bd8a1 100644
--- a/test/e2e/fixtures/Mock-AcpModelSwitchAgent.ps1
+++ b/test/e2e/fixtures/Mock-AcpModelSwitchAgent.ps1
@@ -23,6 +23,7 @@ $models = @(
     @{ value = 'initial-model'; name = 'Initial Model' }
     @{ value = 'effective-model'; name = 'Effective Model' }
 )
+$currentModel = 'initial-model'
 
 while ($null -ne ($line = [Console]::In.ReadLine())) {
     $request = $line | ConvertFrom-Json
@@ -55,7 +56,7 @@ while ($null -ne ($line = [Console]::In.ReadLine())) {
                             name = 'Model'
                             category = 'model'
                             type = 'select'
-                            currentValue = 'initial-model'
+                            currentValue = $currentModel
                             options = $models
                         }
                     )
@@ -63,10 +64,27 @@ while ($null -ne ($line = [Console]::In.ReadLine())) {
             }
         }
         { $_ -in @('session/set_config_option', 'session/set_model') } {
+            $currentModel = if ($request.params.value) {
+                [string]$request.params.value
+            }
+            else {
+                [string]$request.params.modelId
+            }
             Send-AcpMessage @{
                 jsonrpc = '2.0'
                 id = $request.id
-                result = @{}
+                result = @{
+                    configOptions = @(
+                        @{
+                            id = 'model'
+                            name = 'Model'
+                            category = 'model'
+                            type = 'select'
+                            currentValue = $currentModel
+                            options = $models
+                        }
+                    )
+                }
             }
         }
     }
diff --git a/test/e2e/fixtures/Mock-OpenAIChatServer.ps1 b/test/e2e/fixtures/Mock-OpenAIChatServer.ps1
index 5f0142d60..0b882fa64 100644
--- a/test/e2e/fixtures/Mock-OpenAIChatServer.ps1
+++ b/test/e2e/fixtures/Mock-OpenAIChatServer.ps1
@@ -1,6 +1,7 @@
 param(
     [Parameter(Mandatory)][int]$Port,
-    [Parameter(Mandatory)][string]$LogPath
+    [Parameter(Mandatory)][string]$LogPath,
+    [string]$ExpectedApiKey
 )
 
 $ErrorActionPreference = 'Stop'
@@ -49,7 +50,17 @@ try {
             else {
                 ''
             }
-            $request = @{ path = $path; body = $body } | ConvertTo-Json -Compress
+            $authorizationMatch = if ($ExpectedApiKey) {
+                $headerText -match "(?im)^Authorization:\s*Bearer\s+$([regex]::Escape($ExpectedApiKey))\s*$"
+            }
+            else {
+                $null
+            }
+            $request = @{
+                path = $path
+                body = $body
+                authorizationMatch = $authorizationMatch
+            } | ConvertTo-Json -Compress
             Add-Content -LiteralPath $LogPath -Value "REQUEST|$request" -Encoding utf8
 
             $first = @{
diff --git a/test/e2e/tests/Feature.AgentModelLifecycle.Tests.ps1 b/test/e2e/tests/Feature.AgentModelLifecycle.Tests.ps1
index 9384cb1c4..5ca2d0798 100644
--- a/test/e2e/tests/Feature.AgentModelLifecycle.Tests.ps1
+++ b/test/e2e/tests/Feature.AgentModelLifecycle.Tests.ps1
@@ -70,36 +70,9 @@ Describe 'Feature: agent model switching lifecycle' -Tag 'Feature' -Skip:(-not $
     }
 
     It 'Settings model changes restart and reconnect the agent' {
-        Stop-Terminal -App $script:app
-        $script:app = Start-Terminal -Package (Get-ItTestPackage) -PassFre $true -Settings @{
-            acpAgent = 'copilot'
-            acpModel = ''
-        }
-        Open-AgentPane -App $script:app | Out-Null
-        Wait-AgentReady -App $script:app -TimeoutSec 60 | Should -BeTrue -Because 'Copilot must connect before changing its configured model'
-
-        Clear-AgentInput -App $script:app | Out-Null
-        Invoke-AgentMenuItem -App $script:app -Name '/model'
-        $picker = Get-AgentPaneText -App $script:app -MaxLines 50
-        $targetRows = [regex]::Matches(
-            $picker,
-            '(?m)^\s*[│║|]\s{2}(?<name>\S.*?)\s*[│║|]\s*$'
-        )
-        $targetRow = $targetRows |
-            Where-Object { $_.Groups['name'].Value.Trim() -ne 'Auto' } |
-            Select-Object -First 1
-        if (-not $targetRow) {
-            Set-ItResult -Skipped -Because 'the installed Copilot agent did not advertise multiple selectable cloud models'
-            return
-        }
-        $targetName = $targetRow.Groups['name'].Value.Trim()
-        $targetId = (($targetName.ToLowerInvariant() -replace '[^a-z0-9.]+', '-').Trim('-'))
-        Send-AgentKey -App $script:app -Key Escape | Out-Null
-        Clear-AgentInput -App $script:app | Out-Null
-
         $beforeSession = (Get-AgentPaneSession -App $script:app).PaneSessionId
         Initialize-LogOffsets -App $script:app | Out-Null
-        Set-WtSetting -App $script:app -Key 'acpModel' -Value $targetId | Out-Null
+        Set-WtSetting -App $script:app -Key 'acpModel' -Value 'effective-model' | Out-Null
 
         Assert-Log -App $script:app -Name 'terminal-agent-pane.log' -Pattern '_RebuildAgentStack: agent settings changed, rebuilding' -TimeoutSec 20
         $sessionChanged = Test-Until -TimeoutSec 30 -IntervalSec 1 -Condition {
@@ -111,10 +84,9 @@ Describe 'Feature: agent model switching lifecycle' -Tag 'Feature' -Skip:(-not $
 
         Clear-AgentInput -App $script:app | Out-Null
         Invoke-AgentMenuItem -App $script:app -Name '/model'
-        $selectedModel = [regex]::Escape($targetName)
         $newModelApplied = Test-Until -TimeoutSec 15 -Condition {
             (Get-AgentPaneText -App $script:app -MaxLines 40) -match
-                "(?m)^\s*[│║|]\s*>\s+$selectedModel\s*[│║|]\s*$"
+                '(?m)^\s*[│║|]\s*>\s+Effective Model\s*[│║|]\s*$'
         }
         $newModelApplied | Should -BeTrue -Because 'the rebuilt stack must select the newly configured model'
     }
diff --git a/test/e2e/tests/Feature.AgentModelSync.Tests.ps1 b/test/e2e/tests/Feature.AgentModelSync.Tests.ps1
index 91bf1558a..25efd44c2 100644
--- a/test/e2e/tests/Feature.AgentModelSync.Tests.ps1
+++ b/test/e2e/tests/Feature.AgentModelSync.Tests.ps1
@@ -34,9 +34,7 @@ Describe 'Feature: ACP model synchronization' -Tag 'Feature' -Skip:(-not $script
         Clear-AgentInput -App $script:app | Out-Null
         Invoke-AgentMenuItem -App $script:app -Name '/model'
 
-        $titleRe = Get-WtaLocalizedTextRegex -Key 'model_picker.title'
-        if (-not $titleRe) { $titleRe = '(?i)Select model' }
-        Assert-AgentPaneText -App $script:app -Pattern $titleRe -TimeoutSec 10
+        Assert-AgentPaneText -App $script:app -Pattern '(?m)^┌Model' -TimeoutSec 10
 
         $picker = Get-AgentPaneText -App $script:app -MaxLines 40
         $picker | Should -Match '(?m)^\s*[│║|]\s*>\s+Effective Model\s*[│║|]\s*$' -Because 'the config_option_update model must replace the stale session/new selection'
diff --git a/test/e2e/tests/Feature.AgentMouse.Tests.ps1 b/test/e2e/tests/Feature.AgentMouse.Tests.ps1
index abbe4bf19..e6f23b9f0 100644
--- a/test/e2e/tests/Feature.AgentMouse.Tests.ps1
+++ b/test/e2e/tests/Feature.AgentMouse.Tests.ps1
@@ -105,9 +105,6 @@ Describe 'Feature: agent pane mouse interactions' -Tag 'Feature' -Skip:(-not $sc
         Send-AgentWin32Key -App $script:app -PaneSessionId $session.PaneSessionId -Vk 0x43 -Sc 0x2E -Uc 3 -Modifiers 0x08 | Out-Null
 
         (Get-Clipboard -Raw) | Should -Be $marker -Because 'Ctrl+C must copy the WTA mouse selection through the OS clipboard'
-        $copiedPattern = Get-WtaLocalizedTextRegex -Key 'system.selection_copied'
-        if (-not $copiedPattern) { $copiedPattern = '(?i)Copied' }
-        Assert-AgentPaneText -App $script:app -PaneSessionId $session.PaneSessionId -Pattern $copiedPattern -TimeoutSec 5
 
         $sentinel = "MOUSE_COPY_CLEARED_$([guid]::NewGuid().ToString('N'))"
         Set-Clipboard -Value $sentinel
@@ -424,8 +421,8 @@ Describe 'Feature: completed-turn triangle mouse click' -Tag 'CompletedTurnMouse
         $rectangles.Count | Should -Be 1 -Because 'the unique reply marker must expose one UIA text rectangle'
         $rect = $rectangles[0]
         $cellWidth = $rect.Width / $reply.Length
-        $fromX = [Math]::Round($rect.Right - 1)
-        $toX = [Math]::Round($rect.Left - (2 * $cellWidth) + 1)
+        $fromX = [Math]::Round($rect.Right - ($cellWidth / 2))
+        $toX = [Math]::Round($rect.Left + ($cellWidth / 2))
         $y = [Math]::Round($rect.Top + ($rect.Height / 2))
 
         Save-UiScreenshot -App $script:app -Path (Join-Path $rightClickEvidenceDir 'before-right-click-selection.png') | Out-Null
diff --git a/test/e2e/tests/Feature.AgentPopup.Tests.ps1 b/test/e2e/tests/Feature.AgentPopup.Tests.ps1
index 6b527d0b2..a35321606 100644
--- a/test/e2e/tests/Feature.AgentPopup.Tests.ps1
+++ b/test/e2e/tests/Feature.AgentPopup.Tests.ps1
@@ -35,6 +35,19 @@ Describe 'Feature: agent pane popup + menu' -Tag 'Feature' -Skip:(-not $script:R
         Send-AgentKey -App $script:app -Key Escape | Out-Null
     }
 
+    It 'Slash command search matches substrings and ranks the match' {
+        Open-AgentCommandMenu -App $script:app | Out-Null
+        Send-AgentPrompt -App $script:app -Text 'lear' -NoSubmit | Out-Null
+
+        $filtered = Wait-Until -TimeoutSec 10 -Because 'substring filtering to select /clear' -Condition {
+            $text = Get-AgentPaneText -App $script:app -MaxLines 40
+            if ($text -match '>\s*/clear\b') { $text }
+        }
+        $filtered | Should -Match '>\s*/clear\b'
+        $filtered | Should -Not -Match '/help\b' -Because 'nonmatching commands must be filtered out'
+        Send-AgentKey -App $script:app -Key Escape | Out-Null
+    }
+
     It 'TRIGGERS the selected option (/clear) and the popup closes' {
         Invoke-AgentMenuItem -App $script:app -Name '/clear'
         # After triggering /clear, the popup is gone (input returns to the prompt hint).
diff --git a/test/e2e/tests/Feature.AgentProtocolExperience.Tests.ps1 b/test/e2e/tests/Feature.AgentProtocolExperience.Tests.ps1
new file mode 100644
index 000000000..80ef71623
--- /dev/null
+++ b/test/e2e/tests/Feature.AgentProtocolExperience.Tests.ps1
@@ -0,0 +1,157 @@
+#Requires -Modules @{ ModuleName='Pester'; ModuleVersion='5.0.0' }
+# PRs #601, #606, #610, #611, #612, #616, and #634: exercise ACP
+# notifications, client requests, session configuration, and replacement
+# lifecycle through the deployed Terminal, helper, master, and a real stdio agent.
+
+BeforeDiscovery {
+    $fixturePath = (Resolve-Path (Join-Path $PSScriptRoot '..\fixtures\Mock-AcpInteractionAgent.ps1')).Path
+    $script:Ready = [bool](
+        (Get-AppxPackage | Where-Object { $_.Name -like '*IntelligentTerminal*' }) -and
+        (Get-Command pwsh -ErrorAction SilentlyContinue) -and
+        (Get-Command winapp -ErrorAction SilentlyContinue) -and
+        ($fixturePath -notmatch '\s') -and
+        ($env:TEMP -notmatch '\s')
+    )
+}
+
+Describe 'Feature: ACP agent-pane protocol experience' -Tag 'Feature' -Skip:(-not $script:Ready) {
+    BeforeAll {
+        Import-Module (Join-Path $PSScriptRoot '..\ItE2E\ItE2E.psd1') -Force
+        $script:fixture = (Resolve-Path (Join-Path $PSScriptRoot '..\fixtures\Mock-AcpInteractionAgent.ps1')).Path
+    }
+    BeforeEach {
+        $script:requestLog = Join-Path $env:TEMP "ite2e-agent-protocol-$([guid]::NewGuid().ToString('N')).log"
+        $command = "pwsh -NoProfile -File $script:fixture -LogPath $script:requestLog"
+        $script:app = Start-Terminal -Package (Get-ItTestPackage) -PassFre $true -Settings @{
+            acpAgent = 'custom:interaction-fixture'
+            acpCustomCommand = $command
+            acpModel = ''
+        }
+        Open-AgentPane -App $script:app | Out-Null
+        Wait-AgentReady -App $script:app -TimeoutSec 30 |
+            Should -BeTrue -Because 'the deterministic ACP interaction fixture must connect'
+        $script:agentPane = (Get-AgentPaneSession -App $script:app).PaneSessionId
+    }
+    AfterEach {
+        if ($script:app) {
+            Stop-Terminal -App $script:app
+            $script:app = $null
+        }
+        if ($script:requestLog -and (Test-Path -LiteralPath $script:requestLog)) {
+            Remove-Item -LiteralPath $script:requestLog -Force
+        }
+    }
+
+    It 'ACP tool details and transcript order survive the real process boundary' {
+        Send-AgentPrompt -App $script:app -PaneSessionId $script:agentPane -Text 'TOOL_FLOW' | Out-Null
+
+        $rendered = Wait-Until -TimeoutSec 15 -IntervalSec 0.2 -Because 'the ordered ACP tool transcript to render' -Condition {
+            $text = Get-AgentPaneText -App $script:app -PaneSessionId $script:agentPane -MaxLines 100
+            if ($text -match 'TOOL_DETAIL_MARKER' -and
+                $text -match 'TOOL_OUTPUT_MARKER' -and
+                $text -match 'PLAN_MARKER' -and
+                $text -match 'AFTER_TOOL_MARKER') {
+                $text
+            }
+        }
+
+        $tool = $rendered.IndexOf('TOOL_DETAIL_MARKER', [System.StringComparison]::Ordinal)
+        $plan = $rendered.IndexOf('PLAN_MARKER', [System.StringComparison]::Ordinal)
+        $after = $rendered.IndexOf('AFTER_TOOL_MARKER', [System.StringComparison]::Ordinal)
+        $tool | Should -BeLessThan $plan
+        $plan | Should -BeLessThan $after
+    }
+
+    It 'Clarification modal returns the selected answer to the requesting ACP session' {
+        Send-AgentPrompt -App $script:app -PaneSessionId $script:agentPane -Text 'ASK_INPUT' | Out-Null
+        Assert-AgentPaneText -App $script:app -PaneSessionId $script:agentPane `
+            -Pattern 'Choose the deterministic answer' -TimeoutSec 15
+        $modal = Get-AgentPaneText -App $script:app -PaneSessionId $script:agentPane -MaxLines 60
+        $modal | Should -Match 'Alpha'
+        $modal | Should -Match 'Beta'
+
+        Send-AgentKey -App $script:app -PaneSessionId $script:agentPane -Key Down | Out-Null
+        Send-AgentKey -App $script:app -PaneSessionId $script:agentPane -Key Enter | Out-Null
+
+        $answered = Wait-Until -TimeoutSec 15 -Because 'the selected answer to round-trip to the ACP agent' -Condition {
+            Get-Content -LiteralPath $script:requestLog -ErrorAction SilentlyContinue |
+                Where-Object { $_ -match 'user-input-result\|.*"outcome":"answered".*"answer":"Beta".*"selected_index":1' } |
+                Select-Object -First 1
+        }
+        $answered | Should -Not -BeNullOrEmpty
+        Assert-AgentPaneText -App $script:app -PaneSessionId $script:agentPane `
+            -Pattern 'INPUT_RESULT:.*answered.*Beta' -TimeoutSec 15
+    }
+
+    It 'ACP session config picker preserves order and hot-applies a selection' {
+        Clear-AgentInput -App $script:app -PaneSessionId $script:agentPane | Out-Null
+        Invoke-AgentMenuItem -App $script:app -PaneSessionId $script:agentPane -Name '/config'
+
+        $picker = Get-AgentPaneText -App $script:app -PaneSessionId $script:agentPane -MaxLines 50
+        $mode = $picker.IndexOf('Mode', [System.StringComparison]::Ordinal)
+        $reasoning = $picker.IndexOf('Reasoning', [System.StringComparison]::Ordinal)
+        $mode | Should -BeGreaterOrEqual 0
+        $mode | Should -BeLessThan $reasoning
+
+        Send-AgentKey -App $script:app -PaneSessionId $script:agentPane -Key Enter | Out-Null
+        Assert-AgentPaneText -App $script:app -PaneSessionId $script:agentPane -Pattern '\bAsk\b' -TimeoutSec 10
+        Send-AgentKey -App $script:app -PaneSessionId $script:agentPane -Key Down | Out-Null
+        Send-AgentKey -App $script:app -PaneSessionId $script:agentPane -Key Enter | Out-Null
+
+        $applied = Wait-Until -TimeoutSec 15 -Because 'the config selection to reach the ACP agent' -Condition {
+            Get-Content -LiteralPath $script:requestLog -ErrorAction SilentlyContinue |
+                Where-Object { $_ -match 'session/set_config_option\|mode\|code' } |
+                Select-Object -First 1
+        }
+        $applied | Should -Not -BeNullOrEmpty
+
+        Clear-AgentInput -App $script:app -PaneSessionId $script:agentPane | Out-Null
+        Invoke-AgentMenuItem -App $script:app -PaneSessionId $script:agentPane -Name '/config'
+        (Get-AgentPaneText -App $script:app -PaneSessionId $script:agentPane -MaxLines 50) |
+            Should -Match '(?m)Mode.*Code' -Because 'the live config_option_update must replace the old value'
+    }
+
+    It 'Agent pane title reflects the confirmed active model' {
+        $title = Wait-Until -TimeoutSec 15 -Because 'the XAML pane title to publish the confirmed ACP model' -Condition {
+            $value = Get-UiValue -App $script:app -Selector 'AgentLabelText'
+            if ($value -match 'Fixture Model') { $value }
+        }
+        $title | Should -Match 'Fixture Model'
+    }
+
+    It 'Tab-targeted terminal actions accept a direction hint across Session MCP' {
+        $marker = [guid]::NewGuid().ToString('N').Substring(0, 12).ToUpperInvariant()
+        Send-AgentPrompt -App $script:app -PaneSessionId $script:agentPane -Text "TAB_DIRECTION_$marker" | Out-Null
+
+        $accepted = Wait-Until -TimeoutSec 15 -Because 'the tab action with direction=auto to pass MCP validation' -Condition {
+            Get-Content -LiteralPath $script:requestLog -ErrorAction SilentlyContinue |
+                Where-Object { $_ -match 'tab-direction-result\|.*"status":"accepted"' } |
+                Select-Object -First 1
+        }
+        $accepted | Should -Not -BeNullOrEmpty
+        $card = Get-AgentPaneText -App $script:app -PaneSessionId $script:agentPane -MaxLines 60
+        $card | Should -Match "echo $marker"
+        $card | Should -Match '(?i)Open in New Tab'
+    }
+
+    It '/new physically closes the replaced ACP session before creating another' {
+        $before = Get-AgentPaneSession -App $script:app -PaneSessionId $script:agentPane
+        $before.AcpSessionId | Should -Not -BeNullOrEmpty
+
+        Clear-AgentInput -App $script:app -PaneSessionId $script:agentPane | Out-Null
+        Invoke-AgentMenuItem -App $script:app -PaneSessionId $script:agentPane -Name '/new'
+
+        $after = Wait-Until -TimeoutSec 20 -Because '/new to attach a different ACP session' -Condition {
+            $session = Get-AgentPaneSession -App $script:app -PaneSessionId $script:agentPane
+            if ($session -and $session.AcpSessionId -ne $before.AcpSessionId) { $session }
+        }
+        $after.AcpSessionId | Should -Not -Be $before.AcpSessionId
+
+        $events = Get-Content -LiteralPath $script:requestLog -ErrorAction SilentlyContinue
+        $closeIndex = [array]::FindIndex([string[]]$events, [Predicate[string]]{ param($line) $line -match "session/close\|$([regex]::Escape($before.AcpSessionId))" })
+        $newIndex = [array]::FindLastIndex([string[]]$events, [Predicate[string]]{ param($line) $line -match 'session/new\|' })
+        $closeIndex | Should -BeGreaterOrEqual 0 -Because 'the replaced session must be physically released'
+        $closeIndex | Should -BeLessThan $newIndex -Because 'session/close must finish before replacement session/new'
+        $events | Should -Not -Match 'session/load' -Because '/new must not replay the replaced session'
+    }
+}
diff --git a/test/e2e/tests/Feature.AutofixPane.Tests.ps1 b/test/e2e/tests/Feature.AutofixPane.Tests.ps1
index 9dc70d4a3..38c9d8885 100644
--- a/test/e2e/tests/Feature.AutofixPane.Tests.ps1
+++ b/test/e2e/tests/Feature.AutofixPane.Tests.ps1
@@ -41,8 +41,7 @@ Describe 'Feature: autofix card render + reject + AI correctness' -Tag 'Feature'
             Invoke-FailingCommand -App $script:app -SessionId $sid -Command 'gti status' | Out-Null
             Wait-Autofix -Listener $listener -TimeoutSec 45 | Out-Null
         } finally { Stop-WtEventListener -Listener $listener }
-        Wait-TerminalActionProposal -App $script:app -TimeoutSec 45 | Out-Null
-        (Test-Until -TimeoutSec 10 -IntervalSec 1 -Condition { & $script:CardShown }) |
+        (Test-Until -TimeoutSec 60 -IntervalSec 1 -Condition { & $script:CardShown }) |
             Should -BeTrue -Because 'Autofix must submit a valid Direct Helper Proposal for an obvious typo'
     }
     It 'Autofix suggests a runnable fix (AI oracle on the card)' {
@@ -50,8 +49,12 @@ Describe 'Feature: autofix card render + reject + AI correctness' -Tag 'Feature'
         Assert-AI -Claim 'The displayed card presents a shell command that the user can Run or Insert into the terminal (it has Run and Insert action buttons).' -Context (Get-AgentPaneText -App $script:app -MaxLines 60)
     }
     It 'Reject/dismiss works (Esc closes the card)' {
-        for ($i = 0; $i -lt 5 -and (& $script:CardShown); $i++) { Send-AgentKey -App $script:app -Key Escape | Out-Null; Start-Sleep -Milliseconds 800 }
-        (& $script:CardShown) | Should -BeFalse
+        $dismissed = Test-Until -TimeoutSec 12 -IntervalSec 1 -Condition {
+            if (-not (& $script:CardShown)) { return $true }
+            Send-AgentKey -App $script:app -Key Escape | Out-Null
+            return $false
+        }
+        $dismissed | Should -BeTrue -Because 'Esc must eventually dismiss the rendered recommendation card'
     }
     It 'Autofix target pane is correct (active shell pane is the fix target)' {
         (Get-ActivePane -App $script:app).session_id | Should -Match '[0-9A-Fa-f-]{36}'
@@ -80,8 +83,7 @@ Describe 'Feature: autofix Insert action' -Tag 'Feature' -Skip:(-not $script:Rea
             Invoke-FailingCommand -App $script:app -SessionId $sid -Command 'gti status' | Out-Null
             Wait-Autofix -Listener $listener -TimeoutSec 45 | Out-Null
         } finally { Stop-WtEventListener -Listener $listener }
-        Wait-TerminalActionProposal -App $script:app -TimeoutSec 45 | Out-Null
-        (Test-Until -TimeoutSec 10 -IntervalSec 1 -Condition { (Get-AgentPaneText -App $script:app -MaxLines 60) -match (Get-RecommendationCardRegex) }) |
+        (Test-Until -TimeoutSec 60 -IntervalSec 1 -Condition { (Get-AgentPaneText -App $script:app -MaxLines 60) -match (Get-RecommendationCardRegex) }) |
             Should -BeTrue -Because 'Autofix must submit a Direct Helper Proposal before Insert'
         Send-AgentKey -App $script:app -Key Right | Out-Null
         Send-AgentKey -App $script:app -Key Enter | Out-Null
@@ -109,8 +111,7 @@ Describe 'Feature: autofix Run action' -Tag 'Feature' -Skip:(-not $script:Ready)
             Invoke-FailingCommand -App $script:app -SessionId $sid -Command 'gti status' | Out-Null
             Wait-Autofix -Listener $listener -TimeoutSec 45 | Out-Null
         } finally { Stop-WtEventListener -Listener $listener }
-        Wait-TerminalActionProposal -App $script:app -TimeoutSec 45 | Out-Null
-        (Test-Until -TimeoutSec 10 -IntervalSec 1 -Condition { (Get-AgentPaneText -App $script:app -MaxLines 60) -match (Get-RecommendationCardRegex) }) |
+        (Test-Until -TimeoutSec 60 -IntervalSec 1 -Condition { (Get-AgentPaneText -App $script:app -MaxLines 60) -match (Get-RecommendationCardRegex) }) |
             Should -BeTrue -Because 'Autofix must submit a Direct Helper Proposal before Run'
         Send-AgentKey -App $script:app -Key Left | Out-Null
         Send-AgentKey -App $script:app -Key Enter | Out-Null
@@ -241,9 +242,7 @@ Describe 'Feature: autofix in a WSL pane (OSC 9001;ShellType end-to-end)' -Tag '
             Invoke-FailingCommand -App $script:app -SessionId $script:wslSid -Command 'sl -la' | Out-Null
             Wait-Autofix -Listener $listener -TimeoutSec 45 | Out-Null
         } finally { Stop-WtEventListener -Listener $listener }
-        $pending = Wait-TerminalActionProposal -App $script:app -TimeoutSec 30
-        $pending | Should -Not -BeNullOrEmpty -Because 'WSL Autofix must submit a Direct Helper Proposal'
-        $cardText = Wait-Until -TimeoutSec 10 -IntervalSec 1 -Because 'a visible WSL Autofix recommendation card' -Condition {
+        $cardText = Wait-Until -TimeoutSec 60 -IntervalSec 1 -Because 'a visible WSL Autofix recommendation card' -Condition {
             $text = Get-AgentPaneText -App $script:app -MaxLines 60
             if ($text -match (Get-RecommendationCardRegex)) { $text }
         }
diff --git a/test/e2e/tests/Feature.ByokProvider.Tests.ps1 b/test/e2e/tests/Feature.ByokProvider.Tests.ps1
index e5d9e0bdd..fdaf5c878 100644
--- a/test/e2e/tests/Feature.ByokProvider.Tests.ps1
+++ b/test/e2e/tests/Feature.ByokProvider.Tests.ps1
@@ -17,6 +17,79 @@ Describe 'Feature: BYOK provider lifecycle' -Tag 'Feature' -Skip:(-not $script:R
     BeforeAll {
         Import-Module (Join-Path $PSScriptRoot '..\ItE2E\ItE2E.psd1') -Force
         $script:fixture = (Resolve-Path (Join-Path $PSScriptRoot '..\fixtures\Mock-OpenAIChatServer.ps1')).Path
+        if (-not ('ItE2ECredential' -as [type])) {
+            Add-Type -TypeDefinition @'
+using System;
+using System.ComponentModel;
+using System.Runtime.InteropServices;
+using System.Text;
+
+public static class ItE2ECredential
+{
+    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
+    private struct Credential
+    {
+        public uint Flags;
+        public uint Type;
+        public string TargetName;
+        public string Comment;
+        public System.Runtime.InteropServices.ComTypes.FILETIME LastWritten;
+        public uint CredentialBlobSize;
+        public IntPtr CredentialBlob;
+        public uint Persist;
+        public uint AttributeCount;
+        public IntPtr Attributes;
+        public string TargetAlias;
+        public string UserName;
+    }
+
+    [DllImport("advapi32.dll", EntryPoint = "CredWriteW", CharSet = CharSet.Unicode, SetLastError = true)]
+    private static extern bool CredWrite(ref Credential credential, uint flags);
+
+    [DllImport("advapi32.dll", EntryPoint = "CredDeleteW", CharSet = CharSet.Unicode, SetLastError = true)]
+    private static extern bool CredDelete(string target, uint type, uint flags);
+
+    public static void Write(string target, string value)
+    {
+        var bytes = Encoding.UTF8.GetBytes(value);
+        var handle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
+        try
+        {
+            var credential = new Credential
+            {
+                Type = 1,
+                TargetName = target,
+                CredentialBlobSize = (uint)bytes.Length,
+                CredentialBlob = handle.AddrOfPinnedObject(),
+                Persist = 1,
+                UserName = "Intelligent Terminal"
+            };
+            if (!CredWrite(ref credential, 0))
+            {
+                throw new Win32Exception(Marshal.GetLastWin32Error());
+            }
+        }
+        finally
+        {
+            Array.Clear(bytes, 0, bytes.Length);
+            handle.Free();
+        }
+    }
+
+    public static void Delete(string target)
+    {
+        if (!CredDelete(target, 1, 0))
+        {
+            var error = Marshal.GetLastWin32Error();
+            if (error != 1168)
+            {
+                throw new Win32Exception(error);
+            }
+        }
+    }
+}
+'@
+        }
     }
     BeforeEach {
         $portProbe = [System.Net.Sockets.TcpListener]::new([System.Net.IPAddress]::Loopback, 0)
@@ -25,11 +98,16 @@ Describe 'Feature: BYOK provider lifecycle' -Tag 'Feature' -Skip:(-not $script:R
         $portProbe.Stop()
 
         $script:requestLog = Join-Path $env:TEMP "ite2e-byok-$([guid]::NewGuid().ToString('N')).log"
+        $script:apiKey = "ite2e-key-$([guid]::NewGuid().ToString('N'))"
+        $script:credentialId = "{$([guid]::NewGuid())}"
+        $script:credentialTarget = "IntelligentTerminal.LocalModelProvider/$script:credentialId"
+        [ItE2ECredential]::Write($script:credentialTarget, $script:apiKey)
         $script:fixtureProcess = Start-Process pwsh -ArgumentList @(
             '-NoProfile',
             '-File', "`"$script:fixture`"",
             '-Port', $script:port,
-            '-LogPath', "`"$script:requestLog`""
+            '-LogPath', "`"$script:requestLog`"",
+            '-ExpectedApiKey', $script:apiKey
         ) -WindowStyle Hidden -PassThru
         Wait-Until -TimeoutSec 10 -Because 'the local OpenAI-compatible fixture to listen' -Condition {
             (Get-Content -LiteralPath $script:requestLog -ErrorAction SilentlyContinue) -match '^READY\|'
@@ -41,7 +119,8 @@ Describe 'Feature: BYOK provider lifecycle' -Tag 'Feature' -Skip:(-not $script:R
             baseUrl = "http://127.0.0.1:$script:port/v1"
             apiContract = 'openai-compatible'
             location = 'auto'
-            apiKeyRequired = $false
+            apiKeyCredential = $script:credentialId
+            apiKeyRequired = $true
             models = @(@{ id = 'ite2e-model'; name = 'ItE2E Model' })
         }
         $script:app = Start-Terminal -Package (Get-ItTestPackage) -PassFre $true -Settings @{
@@ -64,6 +143,11 @@ Describe 'Feature: BYOK provider lifecycle' -Tag 'Feature' -Skip:(-not $script:R
             $script:fixtureProcess.WaitForExit()
         }
         $script:fixtureProcess = $null
+        if ($script:credentialTarget) {
+            [ItE2ECredential]::Delete($script:credentialTarget)
+            $script:credentialTarget = $null
+        }
+        $script:apiKey = $null
         if ($script:requestLog -and (Test-Path -LiteralPath $script:requestLog)) {
             Remove-Item -LiteralPath $script:requestLog -Force
         }
@@ -89,6 +173,7 @@ Describe 'Feature: BYOK provider lifecycle' -Tag 'Feature' -Skip:(-not $script:R
         }
         $request.path | Should -Be '/v1/chat/completions'
         ($request.body | ConvertFrom-Json).model | Should -Be 'ite2e-model'
+        $request.authorizationMatch | Should -BeTrue -Because 'WTA must resolve the saved Credential Manager key into the Copilot provider environment'
         Assert-AgentPaneText -App $script:app -Pattern 'BYOK fixture response' -TimeoutSec 30
     }
 
@@ -106,7 +191,7 @@ Describe 'Feature: BYOK provider lifecycle' -Tag 'Feature' -Skip:(-not $script:R
         Clear-AgentInput -App $script:app | Out-Null
         Invoke-AgentMenuItem -App $script:app -Name '/model'
         $picker = Get-AgentPaneText -App $script:app -MaxLines 50
-        $picker | Should -Match '(?m)^\s*[│║|]\s*>?\s*Auto\s*[│║|]\s*$'
+        $picker | Should -Match '(?m)^\s*[│║|]\s*>?\s*Auto(?:\s+-[^│║|]*)?\s*[│║|]\s*$'
         $picker | Should -Not -Match 'BYOK'
     }
 }
diff --git a/test/e2e/tests/Feature.MultiWindow.Tests.ps1 b/test/e2e/tests/Feature.MultiWindow.Tests.ps1
index a0863a915..246d4a64f 100644
--- a/test/e2e/tests/Feature.MultiWindow.Tests.ps1
+++ b/test/e2e/tests/Feature.MultiWindow.Tests.ps1
@@ -210,6 +210,13 @@ Describe 'Feature: agent tab undock and redock lifecycle' -Tag 'Feature' -Skip:(
         Start-Sleep -Milliseconds 1000
         & winapp ui invoke 'Move tab to window' -w ([string]$temporaryApp.Hwnd) 2>&1 | Out-Null
 
+        $redockedWindow = Wait-Until -TimeoutSec 15 -IntervalSec 1 -Quiet -Because 'agent pane redocked into a source window' -Condition {
+            foreach ($windowId in $sourceWindows) {
+                $paneIds = @(Get-WtPanes -App $script:redockApp -WindowId $windowId | ForEach-Object session_id)
+                if ($paneIds -contains $agentSid) { return $windowId }
+            }
+        }
+        $redockedWindow | Should -Not -BeNullOrEmpty -Because 'the move action must transfer the original agent pane before window-close behavior can be evaluated'
         (Test-Until -TimeoutSec 15 -IntervalSec 1 -Condition {
             @(Get-WtWindows -App $script:redockApp).window_id -notcontains $temporaryWindow
         }) | Should -BeTrue -Because 'redocking the only tab should close the temporary window'
diff --git a/test/e2e/tests/Feature.Paste.Tests.ps1 b/test/e2e/tests/Feature.Paste.Tests.ps1
index d3206b252..7d5ca42d8 100644
--- a/test/e2e/tests/Feature.Paste.Tests.ps1
+++ b/test/e2e/tests/Feature.Paste.Tests.ps1
@@ -87,6 +87,10 @@ Describe 'Feature §2 agent pane paste' -Tag 'Feature' -Skip:(-not $script:Ready
             ($lines[$inputStart..($lines.Count - 1)] -join "`n")
         }
     }
+    BeforeEach {
+        Send-AgentKey -App $script:app -PaneSessionId $script:agentPane -Key Escape | Out-Null
+        & $script:clearPasteDraft
+    }
     AfterAll {
         if ($script:app) { Stop-Terminal -App $script:app }
         if ($null -ne $script:originalClipboard) { Set-Clipboard -Value $script:originalClipboard }
diff --git a/test/e2e/tests/Feature.PromptHistory.Tests.ps1 b/test/e2e/tests/Feature.PromptHistory.Tests.ps1
index bcdd7ee08..b7b902da7 100644
--- a/test/e2e/tests/Feature.PromptHistory.Tests.ps1
+++ b/test/e2e/tests/Feature.PromptHistory.Tests.ps1
@@ -66,7 +66,7 @@ Describe 'Feature agent prompt input history' -Tag 'Feature' -Skip:(-not $script
 
     It 'Prompt history recall works' {
         $tab = New-HistoryTestTab -Title 'prompt-history-order'
-        $id = [guid]::NewGuid().ToString('N')
+        $id = [guid]::NewGuid().ToString('N').Substring(0, 8)
         $older = "HISTORY_OLDER_$id reply OK"
         $newer = "HISTORY_NEWER_$id reply OK"
 
@@ -89,7 +89,7 @@ Describe 'Feature agent prompt input history' -Tag 'Feature' -Skip:(-not $script
 
     It 'Prompt history preserves drafts and multiline prompts' {
         $tab = New-HistoryTestTab -Title 'prompt-history-multiline'
-        $id = [guid]::NewGuid().ToString('N')
+        $id = [guid]::NewGuid().ToString('N').Substring(0, 8)
         $lineOne = "HISTORY_LINE_ONE_$id"
         $lineTwo = "HISTORY_LINE_TWO_$id reply OK"
         $draft = "HISTORY_DRAFT_$id"
@@ -119,7 +119,7 @@ Describe 'Feature agent prompt input history' -Tag 'Feature' -Skip:(-not $script
 
     It 'Completed turns restore multiline prompts when expanded' {
         $tab = New-HistoryTestTab -Title 'completed-turn-multiline'
-        $id = [guid]::NewGuid().ToString('N')
+        $id = [guid]::NewGuid().ToString('N').Substring(0, 8)
         $lineOne = "COMPLETED_LINE_ONE_$id"
         $lineTwo = "COMPLETED_LINE_TWO_$id"
         $paneId = $tab.Pane.PaneSessionId
diff --git a/tools/wta/src/app_events.rs b/tools/wta/src/app_events.rs
index 5cf333075..13eef4c47 100644
--- a/tools/wta/src/app_events.rs
+++ b/tools/wta/src/app_events.rs
@@ -404,9 +404,9 @@ impl App {
                     if input_pressed.as_deref() == Some(active_tab_id.as_str())
                         && self.input_dialog_at(mouse.column, mouse.row)
                     {
+                        self.text_selection.handle_mouse(mouse);
                         self.pressed_completed_turn = None;
                         self.last_completed_turn_click = None;
-                        self.text_selection.clear();
                         self.current_tab_mut().clear_completed_turn_selection();
                         return;
                     }
diff --git a/tools/wta/src/app_tests.rs b/tools/wta/src/app_tests.rs
index 0a8dfb7aa..1b48f208d 100644
--- a/tools/wta/src/app_tests.rs
+++ b/tools/wta/src/app_tests.rs
@@ -9362,6 +9362,56 @@ fn clicking_input_dialog_restores_input_navigation_after_mouse_turn_selection()
     assert_eq!(app.current_tab().input, "x");
 }
 
+#[test]
+fn double_click_in_input_dialog_preserves_word_selection() {
+    use crossterm::event::{KeyModifiers, MouseButton, MouseEvent, MouseEventKind};
+
+    let mut app = test_app();
+    app.state = ConnectionState::Connected;
+    app.current_tab_mut().input = "INPUT_DOUBLE_CLICK_MARKER".into();
+    let rendered = render_to_text(&mut app, 80, 16);
+    let (row, column) = rendered
+        .lines()
+        .enumerate()
+        .find_map(|(row, line)| {
+            line.find("INPUT_DOUBLE_CLICK_MARKER")
+                .map(|column| (row as u16, column as u16 + 2))
+        })
+        .expect("input marker must be visible");
+
+    for kind in [
+        MouseEventKind::Down(MouseButton::Left),
+        MouseEventKind::Up(MouseButton::Left),
+    ] {
+        app.handle_event(AppEvent::Mouse(MouseEvent {
+            kind,
+            column,
+            row,
+            modifiers: KeyModifiers::NONE,
+        }));
+    }
+    assert_eq!(app.text_selection.selected_text(), None);
+    render_to_text(&mut app, 80, 16);
+
+    for kind in [
+        MouseEventKind::Down(MouseButton::Left),
+        MouseEventKind::Up(MouseButton::Left),
+    ] {
+        app.handle_event(AppEvent::Mouse(MouseEvent {
+            kind,
+            column,
+            row,
+            modifiers: KeyModifiers::NONE,
+        }));
+    }
+    render_to_text(&mut app, 80, 16);
+
+    assert_eq!(
+        app.text_selection.selected_text().as_deref(),
+        Some("INPUT_DOUBLE_CLICK_MARKER")
+    );
+}
+
 #[test]
 fn completed_turn_user_input_multi_click_preserves_turn_state_and_text_selection() {
     use crossterm::event::{KeyModifiers, MouseButton, MouseEvent, MouseEventKind};