Copy a session's id, and its transcript, mid-turn (SPEC-52)

app/lib/desktop/chat/panes/pane_header.dart

@@ -9,6 +9,7 @@ import '../../../store/store.dart';
 import '../../../status/status_event.dart';
 import '../../../status/status_providers.dart';
 import '../../../ui/composer/client_commands.dart';
+import '../../../ui/session/session_identity.dart';
 import '../../../ui/widgets/menu_item.dart';
 import '../sidebar_layout.dart';
 import '../title_bar_strip.dart';
@@ -145,6 +146,15 @@ class SessionActionsMenu extends ConsumerWidget {
               ref: ref,
               sessionId: sessionId,
             );
+          case 'details':
+            // Reads state the client already holds (D13) — not capability
+            // gated. `desktop: true` for the anchored popover, `sessionId` so
+            // the open panel watches and fills in live (D19).
+            showSessionIdentity(
+              context: context,
+              desktop: true,
+              sessionId: sessionId,
+            );
           case 'quit':
             _confirmClose(context, ref);
         }
@@ -155,6 +165,11 @@ class SessionActionsMenu extends ConsumerWidget {
           icon: PhosphorIconsLight.pencilSimple,
           label: 'Rename session',
         ),
+        themedMenuItem(
+          value: 'details',
+          icon: PhosphorIconsLight.fingerprint,
+          label: 'Session details',
+        ),
         const PopupMenuDivider(),
         themedMenuItem(
           value: 'quit',

app/lib/desktop/chat/split_view.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart' hide Tab, Split;
+import 'package:flutter/services.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:phosphoricons_flutter/phosphoricons_flutter.dart';
 
@@ -7,6 +8,7 @@ import '../../status/status_event.dart';
 import '../../status/status_providers.dart';
 import '../../store/store.dart';
 import '../../ui/composer/client_commands.dart';
+import '../../ui/session/session_identity.dart';
 import '../../ui/widgets/menu_item.dart';
 import 'desktop_chat_pane.dart';
 import 'groups/agent_picker.dart';
@@ -665,9 +667,11 @@ class _TabChip extends ConsumerWidget {
     );
   }
 
-  /// Tab context menu (right-click / long-press). One item — "Rename session"
-  /// — styled to the design system's primary body scale (`bodyMedium` text
-  /// with a matching 16px glyph).
+  /// Tab context menu (right-click / long-press): **Rename session** and
+  /// **Copy session id**. Deliberately NOT a *Session details…* item (D13): a
+  /// third door onto the same sheet, one pixel from the pane-header kebab on the
+  /// same platform, was cut on review. **Copy session id** stays because it is a
+  /// different job — right-click → one click → the bare id, no dialog.
   Future<void> _showContextMenu(
     BuildContext context,
     WidgetRef ref,
@@ -678,6 +682,23 @@ class _TabChip extends ConsumerWidget {
     if (overlayState == null) return;
     final overlayBox = overlayState.context.findRenderObject();
     if (overlayBox is! RenderBox) return;
+    // Resolved before the `showMenu` await (SPEC-48 D3): `ref` dies with its
+    // widget, and the copy path reports its outcome after an await.
+    final status = ref.status;
+    // The identity is hoisted for the SAME reason, and it is not optional care:
+    // this menu lives in the Navigator's overlay, so it outlives the tab chip
+    // that opened it. Close the tab while the menu is open — a server snapshot
+    // dropping the session does it for real — and a `ref.read` down in the
+    // `copyId` branch would run on a dead `ref` and throw `Cannot use "ref"
+    // after the widget was disposed`, i.e. crash instead of copying.
+    //
+    // The cost is that the id is sampled at menu-open rather than at click. That
+    // is sub-second for a right-click → click, and it is the RIGHT trade here:
+    // the live-filling surface is the panel, which watches (D19). Rejected
+    // alternative: guarding the late read with `context.mounted`, which keeps the
+    // read fresh but leaves `ref` use after an await — the hazard SPEC-48 D3
+    // exists to remove.
+    final identity = ref.read(sessionIdentityProvider(sessionId));
     final selected = await showMenu<String>(
       context: context,
       position: RelativeRect.fromRect(
@@ -691,8 +712,47 @@ class _TabChip extends ConsumerWidget {
           icon: PhosphorIconsLight.pencilSimple,
           label: 'Rename session',
         ),
+        themedMenuItem(
+          value: 'copyId',
+          icon: PhosphorIconsLight.copy,
+          label: 'Copy session id',
+        ),
       ],
     );
+    if (selected == 'copyId') {
+      // The BARE agent session id (D6), not `sessionIdentityText` — that whole
+      // label:value payload is `Copy all`'s job in the panel. No dialog.
+      final id = identity.agentSessionId;
+      if (id == null) {
+        status.warning(
+          'No agent session id yet',
+          source: StatusSources.session,
+          sessionId: sessionId,
+        );
+        return;
+      }
+      // A clipboard write can throw for real (another process holds it on
+      // Windows; the host denies it). Unreported, the user gets neither the id
+      // nor a reason. Same contract as the panel's `Copy all` and `/session id`.
+      try {
+        await Clipboard.setData(ClipboardData(text: id));
+      } catch (e) {
+        status.failure(
+          'Could not copy session id',
+          error: e,
+          source: StatusSources.session,
+          sessionId: sessionId,
+        );
+        return;
+      }
+      status.info(
+        'Session id copied',
+        source: StatusSources.session,
+        detail: id,
+        sessionId: sessionId,
+      );
+      return;
+    }
     if (selected != 'rename' || !context.mounted) return;
     await handleClientCommand(
       '/name',

app/lib/store/models.dart

@@ -1237,6 +1237,8 @@ class Session {
     this.parentId,
     this.handoffReason,
     this.origin,
+    this.agentSessionId,
+    this.transcriptPath,
     this.queued = const [],
   });
 
@@ -1296,6 +1298,18 @@ class Session {
   /// Null on pre-SPEC-46 rows; a plain string so an unknown value never throws.
   final String? origin;
 
+  /// The underlying agent's own session id — pi's ACP `sessionId` (which is pi's
+  /// OWN session uuid, reused by `pi-acp`) or codex's `threadId`. Null for a
+  /// draft, for a back end with no native session concept, and for any server
+  /// older than SPEC-52 (D1).
+  final String? agentSessionId;
+
+  /// Absolute path to the transcript on the SERVER's host, resolved server-side
+  /// (D2/D3) — the app never derives it, because the slug algorithm is pi's and
+  /// the app cannot stat the server's filesystem to check itself. Null for codex
+  /// in P1 (D16) and whenever no file was found (D9).
+  final String? transcriptPath;
+
   /// Messages submitted while the agent was busy that could not be steered into
   /// the running turn (SPEC-35), oldest first. They are delivered one per idle
   /// transition and can be cancelled until then.
@@ -1319,6 +1333,8 @@ class Session {
     String? parentId,
     String? handoffReason,
     String? origin,
+    String? agentSessionId,
+    String? transcriptPath,
     List<QueuedMessage>? queued,
   }) => Session(
     id: id,
@@ -1341,6 +1357,8 @@ class Session {
     parentId: parentId ?? this.parentId,
     handoffReason: handoffReason ?? this.handoffReason,
     origin: origin ?? this.origin,
+    agentSessionId: agentSessionId ?? this.agentSessionId,
+    transcriptPath: transcriptPath ?? this.transcriptPath,
     queued: queued ?? this.queued,
   );
 }

app/lib/transport/codec.dart

@@ -274,13 +274,24 @@ class WireCodec {
               ? j['handoffReason'] as String
               : null,
           origin: j['origin'] is String ? j['origin'] as String : null,
+          // SPEC-52 D1/D9: normalise `''` to null at the edge. A blank string is
+          // what a sloppy server sends for "no value", and it would render a copy
+          // affordance that copies nothing — the placeholder D9 forbids. Doing it
+          // here means nothing above this line has to think about it.
+          agentSessionId: _nonEmpty(j['agentSessionId']),
+          transcriptPath: _nonEmpty(j['transcriptPath']),
           queued: decodeQueued(j['queued']),
         ),
       );
     }
     return out;
   }
 
+  /// A non-empty string, or null. Rejects non-strings too, so a malformed
+  /// snapshot degrades one field instead of failing the whole session list.
+  static String? _nonEmpty(Object? v) =>
+      (v is String && v.isNotEmpty) ? v : null;
+
   /// Decode a session's `queued` array (SPEC-35). Absent/malformed entries yield
   /// an empty queue rather than failing the whole snapshot: a session list is
   /// too important to drop over a pending-message chip.

app/lib/ui/composer/client_commands.dart

@@ -7,6 +7,7 @@
 library;
 
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 import 'package:phosphoricons_flutter/phosphoricons_flutter.dart';
@@ -20,6 +21,7 @@ import '../../status/status_event.dart';
 import '../../status/status_providers.dart';
 import '../widgets/sheet_header.dart';
 import '../widgets/searchable_list_sheet.dart';
+import '../session/session_identity.dart';
 import '../../app/routes.dart';
 
 typedef ClientCmdHandler =
@@ -264,6 +266,71 @@ final List<ClientCommand> clientCommands = <ClientCommand>[
       );
     },
   ),
+  ClientCommand(
+    name: 'session',
+    description: 'Show this session’s identity, or /session id to copy its id',
+    handler: (context, ref, {required sessionId, required arg}) async {
+      // WHY a CLIENT command and not sent to the agent (D7): pi's own `/session`
+      // is an agent command, so in makit's composer it would fall through to
+      // `store.sendMessage` and — mid-turn — land in the server's pending queue,
+      // executing only after the turn it was meant to help you hand off.
+      // Intercepting it here answers at 100% of a turn. This handler returning
+      // (via `handleClientCommand` matching) is the fix for that bug.
+      //
+      // Resolved before any await (SPEC-48 D3, enforced by
+      // `test/status/status_lifetime_test.dart`): `ref` dies with its widget.
+      final status = ref.status;
+      // `/session id` copies ONLY the bare agent session id (D6). The panel's
+      // `Copy all` is the "give me everything" job; this is "give me the id", so
+      // it must not emit the whole label:value payload.
+      if (arg == 'id') {
+        final id = ref.read(sessionIdentityProvider(sessionId)).agentSessionId;
+        if (id == null) {
+          // Say why rather than copying an empty string: a draft (or a back end
+          // with no native session concept) has no id to hand off yet.
+          status.warning(
+            'No agent session id yet',
+            source: StatusSources.session,
+            sessionId: sessionId,
+          );
+          return;
+        }
+        // A clipboard write can throw for real (another process holds it on
+        // Windows; the host denies it). Unreported, the user gets neither the id
+        // nor a reason — so the write is waited on, and only a write that landed
+        // is allowed to claim success. Same contract as the panel's `Copy all`.
+        try {
+          await Clipboard.setData(ClipboardData(text: id));
+        } catch (e) {
+          status.failure(
+            'Could not copy session id',
+            error: e,
+            source: StatusSources.session,
+            sessionId: sessionId,
+          );
+          return;
+        }
+        status.info(
+          'Session id copied',
+          source: StatusSources.session,
+          detail: id,
+          sessionId: sessionId,
+        );
+        return;
+      }
+      // Bare `/session` opens the panel. Presented as a bottom sheet
+      // (`desktop: false`) like the other client commands (`/model`,
+      // `/thinking`): the invocation comes from the composer, where a sheet is
+      // the established surface. `sessionId` is passed so the open panel watches
+      // and fills in live (D19).
+      if (!context.mounted) return;
+      await showSessionIdentity(
+        context: context,
+        desktop: false,
+        sessionId: sessionId,
+      );
+    },
+  ),
   ClientCommand(
     name: 'name',
     description: 'Rename this session (shown in the session list)',