cacheplane
diff --git a/‎apps/cockpit/src/app/cockpit.css‎
Lines changed: 42 additions & 1 deletion b/‎apps/cockpit/src/app/cockpit.css‎
Lines changed: 42 additions & 1 deletion
diff --git a/‎apps/cockpit/src/components/api-mode/api-mode.tsx‎
Lines changed: 2 additions & 2 deletions b/‎apps/cockpit/src/components/api-mode/api-mode.tsx‎
Lines changed: 2 additions & 2 deletions
diff --git a/‎apps/cockpit/src/components/code-mode/code-mode.spec.tsx‎
Lines changed: 168 additions & 3 deletions b/‎apps/cockpit/src/components/code-mode/code-mode.spec.tsx‎
Lines changed: 168 additions & 3 deletions
@@ -205,13 +205,16 @@ pre.shiki {
   font-size: 0.75rem;
 }
 
-/* Shared prose layer — docs + api */
+/* Shared prose layer — docs + api + code mode content */
 .cockpit-prose {
   max-width: 42rem;
+  margin-inline: auto;
   font-size: 0.9rem;
   line-height: 1.7;
   color: var(--ds-text-secondary);
 }
+.cockpit-prose--wide { max-width: 48rem; }
+.cockpit-prose--code { max-width: 56rem; }
 .cockpit-prose h1, .cockpit-prose h2, .cockpit-prose h3 {
   font-family: var(--font-garamond), var(--ds-font-serif);
   color: var(--ds-text-primary);
@@ -231,3 +234,41 @@ pre.shiki {
 .cockpit-prose table.params { border-collapse: collapse; margin: 0.5rem 0; }
 .cockpit-prose table.params th { font-family: var(--font-mono), monospace; font-size: 0.6rem; letter-spacing: 0.06em; text-transform: uppercase; padding-bottom: 0.5rem; border-bottom: 1px solid var(--ds-border); }
 .cockpit-prose table.params td { padding: 0.5rem 0.75rem 0.5rem 0; border-bottom: 1px solid var(--ds-border); }
+
+/* Code-mode file tree */
+.cockpit-file-tree { list-style: none; padding: 0; margin: 0; font-size: 12px; line-height: 1.7; }
+.cockpit-file-tree ul { list-style: none; padding: 0; margin: 0; }
+.cockpit-file-tree__file,
+.cockpit-file-tree__folder {
+  display: flex; align-items: center; gap: 0.4rem; flex: 1; min-width: 0;
+  padding: 3px 0.75rem 3px 0.75rem; background: transparent; border: 0; text-align: left; cursor: pointer;
+  color: var(--ds-text-secondary); font-family: var(--font-mono), "JetBrains Mono", monospace; font-size: 12px;
+  border-left: 2px solid transparent; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
+}
+.cockpit-file-tree__folder { color: var(--ds-text-muted); display: flex; align-items: center; }
+.cockpit-file-tree__caret { font-size: 9px; color: var(--ds-text-muted); width: 0.65rem; flex-shrink: 0; }
+.cockpit-file-tree__label { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.cockpit-file-tree__chip {
+  font-family: var(--font-mono), monospace; font-size: 9px;
+  padding: 1px 5px; border-radius: 3px; margin-right: 0.5rem; flex-shrink: 0;
+  background: var(--ds-accent-surface); color: var(--ds-accent);
+  opacity: 0.85;
+}
+.cockpit-file-tree__file:hover { color: var(--ds-text-primary); }
+.cockpit-file-tree__file[aria-current="true"] {
+  background: var(--ds-accent-surface);
+  color: var(--ds-text-primary);
+  border-left-color: var(--ds-accent);
+}
+
+/* Tab close (×) on Code-mode tabs */
+.cockpit-tab-trigger { display: inline-flex; align-items: center; gap: 0.4rem; }
+.cockpit-tab-trigger__close {
+  display: inline-flex; align-items: center; justify-content: center;
+  width: 0.95rem; height: 0.95rem; border-radius: 0.2rem;
+  color: var(--ds-text-muted); font-size: 0.85rem; line-height: 1;
+  opacity: 0; cursor: pointer;
+}
+.cockpit-tab-trigger:hover .cockpit-tab-trigger__close,
+.cockpit-tab-trigger[data-state="active"] .cockpit-tab-trigger__close { opacity: 1; }
+.cockpit-tab-trigger__close:hover { background: var(--ds-accent-surface); color: var(--ds-text-primary); }
@@ -130,8 +130,8 @@ export function ApiMode({ docSections, hasCodeFiles = false }: ApiModeProps) {
   const pySections = docSections.filter((s) => s.language === 'python');
 
   return (
-    <section aria-label="API mode" className="h-full overflow-auto py-4 px-4 md:px-8">
-      <div className="cockpit-prose" style={{ maxWidth: '48rem' }}>
+    <section aria-label="API mode" className="h-full overflow-auto py-6 px-4 md:px-8">
+      <div className="cockpit-prose cockpit-prose--wide">
         {tsSections.length > 0 ? (
           <div>
             <h3
 
@@ -52,7 +52,7 @@ describe('CodeMode', () => {
     expect(container.textContent).toContain('export default function Page() {}');
 
     const tabs = Array.from(container.querySelectorAll('[role="tab"]'));
-    expect(tabs.map((tab) => tab.textContent)).toEqual(['page.tsx', 'index.ts']);
+    expect(tabs.map((tab) => (tab.textContent ?? '').replace(/×/g, '').trim())).toEqual(['page.tsx', 'index.ts']);
 
     act(() => {
       (tabs[1] as HTMLElement).dispatchEvent(
@@ -105,12 +105,12 @@ describe('CodeMode', () => {
     });
 
     const tabs = Array.from(container.querySelectorAll('[role="tab"]'));
-    const tabLabels = tabs.map((tab) => tab.textContent);
+    const tabLabels = tabs.map((tab) => (tab.textContent ?? '').replace(/×/g, '').trim());
     expect(tabLabels).toContain('app.tsx');
     expect(tabLabels).toContain('system.md');
 
     act(() => {
-      const promptTab = tabs.find((tab) => tab.textContent === 'system.md') as HTMLElement;
+      const promptTab = tabs.find((tab) => (tab.textContent ?? '').replace(/×/g, '').trim() === 'system.md') as HTMLElement;
       promptTab.dispatchEvent(
         new MouseEvent('mousedown', { bubbles: true, cancelable: true, button: 0 })
       );
@@ -119,6 +119,171 @@ describe('CodeMode', () => {
     expect(container.textContent).toContain('You are a helpful assistant.');
   });
 
+  it('pre-opens all code, backend, and prompt files as tabs with the first code file active', () => {
+    container = document.createElement('div');
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    act(() => {
+      root!.render(
+        <CodeMode
+          entryTitle="Planning"
+          codeAssetPaths={['src/a.ts']}
+          backendAssetPaths={['backend/graph.py']}
+          codeFiles={{
+            'src/a.ts': '<pre class="shiki"><code>a</code></pre>',
+            'backend/graph.py': '<pre class="shiki"><code>g</code></pre>',
+          }}
+          promptFiles={{ 'prompts/p.md': 'hello' }}
+        />,
+      );
+    });
+
+    const tabLabels = Array.from(container.querySelectorAll('[role="tab"]')).map((t) => (t.textContent ?? '').replace(/×/g, '').trim());
+    expect(tabLabels).toEqual(['a.ts', 'graph.py', 'p.md']);
+
+    const active = container.querySelector('[role="tab"][data-state="active"]');
+    expect((active?.textContent ?? '').replace(/×/g, '').trim()).toBe('a.ts');
+  });
+
+  it('opens a closed file and activates it when the tree row is clicked', () => {
+    container = document.createElement('div');
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    act(() => {
+      root!.render(
+        <CodeMode
+          entryTitle="Planning"
+          codeAssetPaths={['src/a.ts', 'src/b.ts']}
+          backendAssetPaths={[]}
+          codeFiles={{
+            'src/a.ts': '<pre class="shiki"><code>a</code></pre>',
+            'src/b.ts': '<pre class="shiki"><code>b</code></pre>',
+          }}
+          promptFiles={{}}
+        />,
+      );
+    });
+
+    // Locate the tree row for b.ts and click it. Since FT5 has both files pre-opened,
+    // this verifies the tree-click path even before FT6 introduces close behaviour.
+    const bRow = Array.from(container.querySelectorAll('[data-file-row]')).find(
+      (el) => el.querySelector('[data-file-label]')?.textContent === 'b.ts',
+    ) as HTMLElement;
+    expect(bRow).toBeDefined();
+
+    act(() => { bRow.click(); });
+
+    const active = container.querySelector('[role="tab"][data-state="active"]');
+    expect((active?.textContent ?? '').replace(/×/g, '').trim()).toBe('b.ts');
+  });
+
+  it('closes a tab and activates its left neighbor', () => {
+    container = document.createElement('div');
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    act(() => {
+      root!.render(
+        <CodeMode
+          entryTitle="Planning"
+          codeAssetPaths={['src/a.ts', 'src/b.ts', 'src/c.ts']}
+          backendAssetPaths={[]}
+          codeFiles={{
+            'src/a.ts': '<pre class="shiki"><code>a</code></pre>',
+            'src/b.ts': '<pre class="shiki"><code>b</code></pre>',
+            'src/c.ts': '<pre class="shiki"><code>c</code></pre>',
+          }}
+          promptFiles={{}}
+        />,
+      );
+    });
+
+    // Activate b.ts, then close it.
+    const bTab = Array.from(container.querySelectorAll('[role="tab"]')).find(
+      (el) => el.textContent?.startsWith('b.ts'),
+    ) as HTMLElement;
+    act(() => {
+      bTab.dispatchEvent(new MouseEvent('mousedown', { bubbles: true, cancelable: true, button: 0 }));
+    });
+
+    const closeBtn = container.querySelector('[role="tab"][data-state="active"] [data-tab-close]') as HTMLElement;
+    expect(closeBtn).not.toBeNull();
+    act(() => { closeBtn.click(); });
+
+    const tabs = Array.from(container.querySelectorAll('[role="tab"]')).map((t) =>
+      (t.textContent ?? '').replace(/×/g, '').trim(),
+    );
+    expect(tabs).toEqual(['a.ts', 'c.ts']);
+
+    const active = container.querySelector('[role="tab"][data-state="active"]');
+    expect((active?.textContent ?? '').startsWith('a.ts')).toBe(true);
+  });
+
+  it('shows the empty state after the last tab is closed', () => {
+    container = document.createElement('div');
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    act(() => {
+      root!.render(
+        <CodeMode
+          entryTitle="Planning"
+          codeAssetPaths={['src/only.ts']}
+          backendAssetPaths={[]}
+          codeFiles={{ 'src/only.ts': '<pre class="shiki"><code>x</code></pre>' }}
+          promptFiles={{}}
+        />,
+      );
+    });
+
+    const closeBtn = container.querySelector('[role="tab"] [data-tab-close]') as HTMLElement;
+    act(() => { closeBtn.click(); });
+
+    expect(container.querySelectorAll('[role="tab"]')).toHaveLength(0);
+    expect(container.textContent).toContain('Select a file from the tree');
+  });
+
+  it('closes a tab when Enter is pressed on the close button', () => {
+    container = document.createElement('div');
+    document.body.appendChild(container);
+    root = createRoot(container);
+
+    act(() => {
+      root!.render(
+        <CodeMode
+          entryTitle="Planning"
+          codeAssetPaths={['src/a.ts', 'src/b.ts']}
+          backendAssetPaths={[]}
+          codeFiles={{
+            'src/a.ts': '<pre class="shiki"><code>a</code></pre>',
+            'src/b.ts': '<pre class="shiki"><code>b</code></pre>',
+          }}
+          promptFiles={{}}
+        />,
+      );
+    });
+
+    // The first tab (a.ts) is active by default; its close span is focusable.
+    const closeBtn = container.querySelector(
+      '[role="tab"][data-state="active"] [data-tab-close]',
+    ) as HTMLElement;
+    expect(closeBtn).not.toBeNull();
+    expect(closeBtn.getAttribute('tabindex')).toBe('0');
+
+    act(() => {
+      closeBtn.dispatchEvent(
+        new KeyboardEvent('keydown', { key: 'Enter', bubbles: true, cancelable: true }),
+      );
+    });
+
+    const tabs = Array.from(container.querySelectorAll('[role="tab"]')).map((t) =>
+      (t.textContent ?? '').replace(/×/g, '').trim(),
+    );
+    expect(tabs).toEqual(['b.ts']);
+  });
+
   it('fires cockpit:code_copied when the Copy button is clicked', () => {
     container = document.createElement('div');
     document.body.appendChild(container);