Clear stamped code-block height when Hide Info collapses a tool call

packages/host/app/components/matrix/room-message-tool.gts

@@ -152,17 +152,14 @@ export default class RoomMessageTool extends Component<Signature> {
   };
 
   private scrollBottomIntoView = modifier((element: HTMLElement) => {
-    let editor = this.args.monacoSDK.editor
-      .getEditors()
-      .find((editor) => element.contains(editor.getContainerDomNode()));
-    let editorHeight = editor?.getContentHeight() ?? 0;
-    if (!editorHeight || editorHeight < 0) {
+    // Consume the toggle flag so this re-runs when the code area opens or
+    // closes. The code block sizes to its content on its own — the Monaco
+    // modifier sets the editor's height and CSS caps it — so there is no inline
+    // height to stamp or clear; collapsing the editor lets the block shrink
+    // back to its header. When the code opens, bring it into view.
+    if (!this.isDisplayingCode) {
       return;
     }
-    let heightOfOtherChildren = [...element.children]
-      .filter((childEl) => childEl !== editor?.getContainerDomNode())
-      .reduce((acc, childEl) => acc + (childEl as HTMLElement).offsetHeight, 0);
-    element.style.height = `${editorHeight + heightOfOtherChildren}px`; // max-height is constrained by CSS
     this.scrollIntoView(element.parentElement as HTMLElement);
   });
 
@@ -313,6 +310,7 @@ export default class RoomMessageTool extends Component<Signature> {
           data-test-tool-call-card-idle={{not
             (eq this.applyButtonState 'applying')
           }}
+          data-test-tool-code-block
           as |codeBlock|
         >
           <codeBlock.commandHeader

packages/host/tests/integration/components/ai-assistant-panel/tools-test.gts

@@ -1,4 +1,4 @@
-import { waitFor, click, fillIn } from '@ember/test-helpers';
+import { waitFor, click, fillIn, find } from '@ember/test-helpers';
 import { settled } from '@ember/test-helpers';
 import GlimmerComponent from '@glimmer/component';
 
@@ -1241,6 +1241,148 @@ module('Integration | ai-assistant-panel | tools', function (hooks) {
     await percySnapshot(assert); // can preview code in ViewCode panel
   });
 
+  test('"Hide Info" collapses the code area even after the message re-mounts while expanded', async function (assert) {
+    setCardInOperatorModeState(`${testRealmURL}Person/fadhlan`);
+    await renderComponent(
+      class TestDriver extends GlimmerComponent {
+        <template><OperatorMode @onClose={{noop}} /></template>
+      },
+    );
+    await waitFor('[data-test-person="Fadhlan"]');
+    let roomId = createAndJoinRoom({
+      sender: '@testuser:localhost',
+      name: 'test room 1',
+    });
+
+    simulateRemoteMessage(roomId, '@aibot:localhost', {
+      msgtype: APP_BOXEL_MESSAGE_MSGTYPE,
+      body: 'Changing first name to Evie',
+      format: 'org.matrix.custom.html',
+      isStreamingFinished: true,
+      [APP_BOXEL_TOOL_REQUESTS_KEY]: [
+        {
+          id: 'hide-info-height',
+          name: 'patchCardInstance',
+          arguments: JSON.stringify({
+            attributes: {
+              cardId: `${testRealmURL}Person/fadhlan`,
+              patch: {
+                attributes: { firstName: 'Evie' },
+              },
+            },
+          }),
+        },
+      ],
+    });
+
+    await settled();
+
+    await click('[data-test-open-ai-assistant]');
+    await waitFor('[data-test-room-name="test room 1"]');
+
+    // Expand the code area.
+    await click('[data-test-view-code-button]');
+    await waitFor('[data-test-editor]');
+
+    // Re-mount the tool-call message while its code area is open: close and
+    // reopen the AI assistant panel. The expanded/collapsed flag lives in the
+    // room resource and survives the remount, so the code area comes back open
+    // and the height-stamping modifier installs with the editor present —
+    // reproducing the condition under which "Hide Info" used to leave an empty
+    // expanded-height block.
+    await click('[data-test-close-ai-assistant]');
+    await click('[data-test-open-ai-assistant]');
+    await waitFor('[data-test-editor]');
+    await settled();
+
+    // Collapse via "Hide Info".
+    await click('[data-test-view-code-button]');
+    assert
+      .dom('[data-test-editor]')
+      .doesNotExist('code editor is removed after Hide Info');
+
+    let codeBlockSelector =
+      '[data-test-tool-call-id="hide-info-height"] [data-test-tool-code-block]';
+    assert.dom(codeBlockSelector).exists('tool code block element exists');
+    let codeBlock = find(codeBlockSelector) as HTMLElement;
+    assert.strictEqual(
+      codeBlock.style.height,
+      '',
+      'no inline height is left behind so the block collapses to its header-only height',
+    );
+  });
+
+  test('expanding a tall tool call does not leave an empty gap below the code', async function (assert) {
+    setCardInOperatorModeState(`${testRealmURL}Person/fadhlan`);
+    await renderComponent(
+      class TestDriver extends GlimmerComponent {
+        <template><OperatorMode @onClose={{noop}} /></template>
+      },
+    );
+    await waitFor('[data-test-person="Fadhlan"]');
+    let roomId = createAndJoinRoom({
+      sender: '@testuser:localhost',
+      name: 'test room 1',
+    });
+
+    // A payload with enough lines that the rendered code exceeds the editor's
+    // 250px max-height cap, so the editor scrolls internally rather than
+    // growing to its full content height.
+    let attributes = Object.fromEntries(
+      Array.from({ length: 30 }, (_, i) => [`field${i}`, `value ${i}`]),
+    );
+    simulateRemoteMessage(roomId, '@aibot:localhost', {
+      msgtype: APP_BOXEL_MESSAGE_MSGTYPE,
+      body: 'Applying a large patch',
+      format: 'org.matrix.custom.html',
+      isStreamingFinished: true,
+      [APP_BOXEL_TOOL_REQUESTS_KEY]: [
+        {
+          id: 'tall-tool-call',
+          name: 'patchCardInstance',
+          arguments: JSON.stringify({
+            attributes: {
+              cardId: `${testRealmURL}Person/fadhlan`,
+              patch: { attributes },
+            },
+          }),
+        },
+      ],
+    });
+
+    await settled();
+
+    await click('[data-test-open-ai-assistant]');
+    await waitFor('[data-test-room-name="test room 1"]');
+
+    await click('[data-test-view-code-button]');
+    await waitFor('[data-test-editor]');
+    await settled();
+
+    let codeBlockSelector =
+      '[data-test-tool-call-id="tall-tool-call"] [data-test-tool-code-block]';
+    assert.dom(codeBlockSelector).exists('tool code block element exists');
+    let codeBlock = find(codeBlockSelector) as HTMLElement;
+
+    // With no stamped inline height the section sizes to its content, so its
+    // height should not exceed the sum of its rendered children. A stamp based
+    // on Monaco's uncapped content height would make the section taller than
+    // the capped editor, leaving an empty gap below the code.
+    assert.strictEqual(
+      codeBlock.style.height,
+      '',
+      'no inline height is stamped when the code is expanded',
+    );
+    let childrenHeight = [...codeBlock.children].reduce(
+      (sum, child) => sum + (child as HTMLElement).offsetHeight,
+      0,
+    );
+    assert.ok(
+      codeBlock.offsetHeight <= childrenHeight + 4,
+      `expanded code block height (${codeBlock.offsetHeight}px) should not exceed its rendered children (${childrenHeight}px)`,
+    );
+  });
+
   test('when command in a message with continuations is done streaming, apply button is shown in ready state', async function (assert) {
     setCardInOperatorModeState(`${testRealmURL}Person/fadhlan`);
     await renderComponent(