diff --git a/packages/app-bundle/manifest.json b/packages/app-bundle/manifest.json
index 75aa28c61..723500b31 100644
--- a/packages/app-bundle/manifest.json
+++ b/packages/app-bundle/manifest.json
@@ -300,7 +300,7 @@
     "packages/app/src/pages/new-session.tsx": "e69db43dfd9f29a3b8920bf63654f40772bfb0ab6d24029c7903a754c94e8571",
     "packages/app/src/pages/overlay-content-hash.test.ts": "aa208098213522dcde42434408afe9c8641fad663f44a58c316922dbd0da2f5c",
     "packages/app/src/pages/research-surfaces-absence.test.ts": "9944a8ec5492500eb82548d03b24ea7fb8ccc9c2ae5de14a4d18ddb309378746",
-    "packages/app/src/pages/session.tsx": "699f8644414fe44aab319c0338d2d3bdb552e1f5bc4d35f8229372b659694b3b",
+    "packages/app/src/pages/session.tsx": "1d71fdafbd3333af6766514ab44d22c11cc855ea82cdcfaf9ea2e0e5330a9736",
     "packages/app/src/utils/amicode-bridge.ts": "3ec87c24c0384d312f7eb644807d9217a53b1b4b97f7fffadab1cc1595603f3b",
     "packages/app/src/utils/amicode-bug-report.test.ts": "b1bbf49230ff3aa6d1a43ffa9165ba5a84ca4ee18a6d49f52ee5cd887c3e6444",
     "packages/app/src/utils/amicode-bug-report.ts": "d55d9cecfe17719c0d4a0ca498345c7eff6fca1de6b645e4bc3fecb40f2f4645",
@@ -900,7 +900,7 @@
     "packages/app/src/pages/session/session-panel-width.test.ts": "9482afba7fbce254cbbd21ef885e9e9620b981616681635376f466478f611155",
     "packages/app/src/pages/session/session-panel-width.ts": "02ee3a02ed78db2eac47c2528055cf78aef95f389641e929ddc56c17471dcbe2",
     "packages/app/src/pages/session/session-side-panel-structure.test.ts": "b2d1d007d9200d0ac4a0889e45c2dbe57a324a10cb26ae9ab8f420d3c890402b",
-    "packages/app/src/pages/session/session-side-panel.tsx": "43cbf60797b5b382e1cc6e69015f242d684ab92eb68f45a5dcef9cf56422d59a",
+    "packages/app/src/pages/session/session-side-panel.tsx": "d6c0cd6cdc2a586ce342b1ef91d68f4560d7c348891e5a83bc9665b671b892e9",
     "packages/app/src/pages/session/terminal-panel-v2.tsx": "68dad9307f1d2abf3ff9248e451bd08005acf01ddc46b30a6d01b58f4a90dce0",
     "packages/app/src/pages/session/use-amicode-commands.test.ts": "65671d054c404edd2b799b0f6591a9c055e6ecb454a674fa0bd9a7fa6f68e111",
     "packages/app/src/pages/session/use-amicode-commands.tsx": "88bfdad9ae6dfd920b8e6a14ffebd2cf9e52b8f67bb9284cb358ad940643ca67",
@@ -1102,7 +1102,7 @@
     "packages/ui/src/v2/components/text-shimmer-v2.tsx"
   ],
   "exceptions": [],
-  "extracted_at": "2026-11-06T18:48:23.336Z",
+  "extracted_at": "2026-11-07T23:24:13.583Z",
   "per_package": {
     "packages/app": {
       "A": 312,
diff --git a/packages/app-bundle/overlay/packages/app/src/pages/session.tsx b/packages/app-bundle/overlay/packages/app/src/pages/session.tsx
index 2851ef02a..dbaa6814b 100644
--- a/packages/app-bundle/overlay/packages/app/src/pages/session.tsx
+++ b/packages/app-bundle/overlay/packages/app/src/pages/session.tsx
@@ -716,6 +716,37 @@ export default function Page() {
   const workColumnWidth = createMemo(() =>
     clampWorkColumnWidth({ width: layout.panelColumn.width(), available: sessionPanelAvailable() }),
   )
+
+  // #1434: Wide mode — a fullscreen toggle for the Work Column that overrides
+  // the normal 60% cap. The resize handle stays bounded; only the toggle goes
+  // full-width. Declared before sessionPanelWidth so it can gate the chat width.
+  const [wideMode, setWideMode] = createSignal(false)
+  const [preWideColumnWidth, setPreWideColumnWidth] = createSignal<number | undefined>(undefined)
+
+  function toggleWide() {
+    if (wideMode()) {
+      setWideMode(false)
+      const restore = preWideColumnWidth()
+      if (restore) layout.panelColumn.resize(restore)
+    } else {
+      setPreWideColumnWidth(layout.panelColumn.width())
+      setWideMode(true)
+    }
+  }
+
+  // Cmd+Shift+M toggles wide mode
+  createEffect(() => {
+    if (!newSessionDesign()) return
+    function onKeyDown(e: KeyboardEvent) {
+      if ((e.metaKey || e.ctrlKey) && e.shiftKey && e.key.toLowerCase() === "m") {
+        e.preventDefault()
+        toggleWide()
+      }
+    }
+    window.addEventListener("keydown", onKeyDown)
+    onCleanup(() => window.removeEventListener("keydown", onKeyDown))
+  })
+
   const sessionPanelWidth = createMemo(() => {
     if (chatTakesRemainder()) return undefined
     if (!desktopSidePanelOpen()) return "100%"
@@ -2820,25 +2851,38 @@ export default function Page() {
     <SessionRouteFrame>
       <SessionHeader />
       <ContextWarningBanner />
-      <div
+       <div
         ref={panelRow}
         class="flex-1 min-h-0 flex flex-col md:flex-row"
         classList={{
-           "gap-1.5 px-1.5 py-2": settings.general.newLayoutDesigns(),
+           "gap-1.5 px-1.5 py-2": settings.general.newLayoutDesigns() && !wideMode(),
+           "py-2": settings.general.newLayoutDesigns() && wideMode(),
         }}
       >
         <Show when={!isDesktop() && !!params.id && !settings.general.newLayoutDesigns()}>{mobileTabs()}</Show>
 
         <div
           classList={{
-            "@container relative shrink-0 flex flex-col min-h-0 h-full transition-[width]": true,
+            "@container relative shrink-0 flex flex-col min-h-0 h-full transition-[width,opacity]": true,
             "flex-1 md:flex-none": !chatTakesRemainder(),
-            "flex-1": chatTakesRemainder(),
+            "flex-1": chatTakesRemainder() && !wideMode(),
             "duration-[240ms] ease-[cubic-bezier(0.22,1,0.36,1)] will-change-[width] motion-reduce:transition-none":
               !size.active() && !ui.reviewSnap && !desktopInlineTerminalOnlyOpen(),
           }}
           style={{
-            width: sessionPanelWidth(),
+            // #1434: in wide mode, collapse Chat completely out of flow.
+            // Use position:absolute + visibility:hidden (not display:none)
+            // to preserve scroll geometry and avoid the #1510 cascade.
+            ...(newSessionDesign() && wideMode() ? {
+              position: "absolute" as const,
+              visibility: "hidden" as const,
+              width: "0px",
+              height: "0px",
+              overflow: "hidden",
+              "pointer-events": "none",
+            } : {
+              width: sessionPanelWidth(),
+            }),
           }}
         >
           {settings.general.newLayoutDesigns() ? (
@@ -2897,15 +2941,16 @@ export default function Page() {
             <div
               classList={{
                 "min-w-0 h-full flex flex-col relative": true,
-                "flex-1": !isDesktop(),
-                "flex-none": isDesktop(),
+                "flex-1": !isDesktop() || wideMode(),
+                "flex-none": isDesktop() && !wideMode(),
               }}
-              style={{ width: isDesktop() ? `${workColumnWidth()}px` : undefined }}
+              style={{ width: isDesktop() && !wideMode() ? `${workColumnWidth()}px` : undefined }}
             >
               {/* amicode#105: the work column's own resize handle (its left
                   edge), sizing layout.panelColumn within the policy bounds —
-                  the chat flexes around it, never below it. */}
-              <Show when={isDesktop()}>
+                  the chat flexes around it, never below it. Hidden in wide
+                  mode since the column fills the row. */}
+              <Show when={isDesktop() && !wideMode()}>
                 <div onPointerDown={() => size.start()}>
                   <ResizeHandle
                     direction="horizontal"
@@ -2942,6 +2987,8 @@ export default function Page() {
                       size={size}
                       stacked={desktopV2PanelLayout().stacked}
                       touchedFiles={touchedFiles}
+                      isWide={wideMode}
+                      onToggleWide={toggleWide}
                     />
                   </Suspense>
                 </div>
diff --git a/packages/app-bundle/overlay/packages/app/src/pages/session/session-side-panel.tsx b/packages/app-bundle/overlay/packages/app/src/pages/session/session-side-panel.tsx
index 58b05f8a2..6c8541519 100644
--- a/packages/app-bundle/overlay/packages/app/src/pages/session/session-side-panel.tsx
+++ b/packages/app-bundle/overlay/packages/app/src/pages/session/session-side-panel.tsx
@@ -333,6 +333,9 @@ export function SessionSidePanel(props: {
   size: Sizing
   stacked?: boolean
   touchedFiles?: () => Array<{ file: string; status: string }>
+  /** #1434: Wide mode toggle */
+  isWide?: () => boolean
+  onToggleWide?: () => void
 }) {
   const layout = useLayout()
   const settings = useSettings()
@@ -922,7 +925,24 @@ export function SessionSidePanel(props: {
                                 </For>
                               </SortableProvider>
                             </Tabs.List>
-                            <div class="shrink-0 flex items-center justify-center pl-2 pr-1">
+                            <div class="shrink-0 flex items-center gap-1 pl-2 pr-1">
+                              {/* #1434: Wide mode toggle pill */}
+                              <Show when={props.onToggleWide}>
+                                <button
+                                  class="flex items-center gap-1 px-2 py-0.5 rounded-full text-[11px] font-medium transition-colors"
+                                  classList={{
+                                    "bg-surface-accent/15 text-text-accent hover:bg-surface-accent/25": props.isWide?.() ?? false,
+                                    "bg-transparent text-text-dimmed hover:bg-background-interactive-hover hover:text-text-base": !(props.isWide?.() ?? false),
+                                  }}
+                                  title={props.isWide?.()
+                                    ? `Exit Wide (${navigator.platform.includes("Mac") ? "⌘" : "Ctrl"}⇧M)`
+                                    : `Wide (${navigator.platform.includes("Mac") ? "⌘" : "Ctrl"}⇧M)`
+                                  }
+                                  onClick={() => props.onToggleWide?.()}
+                                >
+                                  {props.isWide?.() ? "Exit Wide" : "Wide"}
+                                </button>
+                              </Show>
                               <PanelMenu items={panelMenuItems()} onSelect={handlePanelMenuSelect} />
                             </div>
                           </div>
@@ -1297,7 +1317,24 @@ export function SessionSidePanel(props: {
                             </For>
                           </DndKitProvider>
                         </Tabs.List>
-                        <div class="shrink-0 flex items-center justify-center pl-2 pr-1">
+                        <div class="shrink-0 flex items-center gap-1 pl-2 pr-1">
+                          {/* #1434: Wide mode toggle pill (v2 path) */}
+                          <Show when={props.onToggleWide}>
+                            <button
+                              class="flex items-center gap-1 px-2 py-0.5 rounded-full text-[11px] font-medium transition-colors"
+                              classList={{
+                                "bg-surface-accent/15 text-text-accent hover:bg-surface-accent/25": props.isWide?.() ?? false,
+                                "bg-transparent text-text-dimmed hover:bg-background-interactive-hover hover:text-text-base": !(props.isWide?.() ?? false),
+                              }}
+                              title={props.isWide?.()
+                                ? `Exit Wide (${navigator.platform.includes("Mac") ? "⌘" : "Ctrl"}⇧M)`
+                                : `Wide (${navigator.platform.includes("Mac") ? "⌘" : "Ctrl"}⇧M)`
+                              }
+                              onClick={() => props.onToggleWide?.()}
+                            >
+                              {props.isWide?.() ? "Exit Wide" : "Wide"}
+                            </button>
+                          </Show>
                           <PanelMenu items={panelMenuItems()} onSelect={handlePanelMenuSelect} v2 />
                         </div>
                         <div