diff --git a/packages/host/app/components/ai-assistant/attachment-picker/attached-items.gts b/packages/host/app/components/ai-assistant/attachment-picker/attached-items.gts
index 5ecf174a3c..14b292c29d 100644
--- a/packages/host/app/components/ai-assistant/attachment-picker/attached-items.gts
+++ b/packages/host/app/components/ai-assistant/attachment-picker/attached-items.gts
@@ -33,7 +33,7 @@ interface Signature {
   Args: {
     items: (CardDef | FileDef | CardErrorJSONAPI)[];
     autoAttachedCardIds?: TrackedSet<string>;
-    autoAttachedFile?: FileDef;
+    autoAttachedFiles?: FileDef[];
     removeCard: (cardId: string) => void;
     removeFile: (file: FileDef) => void;
     chooseCard?: (cardId: string) => void;
@@ -63,7 +63,11 @@ export default class AttachedItems extends Component<Signature> {
   };
 
   private isAutoAttachedFile = (file: FileDef): boolean => {
-    return this.args.autoAttachedFile?.sourceUrl === file.sourceUrl;
+    return (
+      this.args.autoAttachedFiles?.some(
+        (autoFile) => autoFile.sourceUrl === file.sourceUrl,
+      ) ?? false
+    );
   };
 
   @action
diff --git a/packages/host/app/components/ai-assistant/attachment-picker/index.gts b/packages/host/app/components/ai-assistant/attachment-picker/index.gts
index 1fa77a4743..27c91b742a 100644
--- a/packages/host/app/components/ai-assistant/attachment-picker/index.gts
+++ b/packages/host/app/components/ai-assistant/attachment-picker/index.gts
@@ -23,7 +23,7 @@ interface Signature {
   Args: {
     autoAttachedCardIds?: TrackedSet<string>;
     cardIdsToAttach: string[] | undefined;
-    autoAttachedFile?: FileDef;
+    autoAttachedFiles?: FileDef[];
     filesToAttach: FileDef[] | undefined;
     chooseCard: (cardId: string) => void;
     removeCard: (cardId: string) => void;
@@ -37,7 +37,7 @@ interface Signature {
         typeof AttachedItems,
         | 'items'
         | 'autoAttachedCardIds'
-        | 'autoAttachedFile'
+        | 'autoAttachedFiles'
         | 'removeCard'
         | 'removeFile'
         | 'chooseCard'
@@ -59,7 +59,7 @@ export default class AiAssistantAttachmentPicker extends Component<Signature> {
         isLoaded=this.isLoaded
         items=this.items
         autoAttachedCardIds=@autoAttachedCardIds
-        autoAttachedFile=@autoAttachedFile
+        autoAttachedFiles=@autoAttachedFiles
         removeCard=@removeCard
         removeFile=@removeFile
         chooseCard=@chooseCard
@@ -109,18 +109,20 @@ export default class AiAssistantAttachmentPicker extends Component<Signature> {
   private get files() {
     let files = this.args.filesToAttach ?? [];
 
-    if (!this.args.autoAttachedFile) {
+    let autoAttachedFiles = this.args.autoAttachedFiles ?? [];
+
+    if (autoAttachedFiles.length === 0) {
       return files;
     }
 
-    if (
-      files.some(
-        (file) => file.sourceUrl === this.args.autoAttachedFile?.sourceUrl,
-      )
-    ) {
+    let autoFilesToPrepend = autoAttachedFiles.filter(
+      (file) => !files.some((item) => item.sourceUrl === file.sourceUrl),
+    );
+
+    if (autoFilesToPrepend.length === 0) {
       return files;
     }
 
-    return [this.args.autoAttachedFile, ...files];
+    return [...autoFilesToPrepend, ...files];
   }
 }
diff --git a/packages/host/app/components/ai-assistant/attachment-picker/usage.gts b/packages/host/app/components/ai-assistant/attachment-picker/usage.gts
index 411deb3821..fa01246732 100644
--- a/packages/host/app/components/ai-assistant/attachment-picker/usage.gts
+++ b/packages/host/app/components/ai-assistant/attachment-picker/usage.gts
@@ -18,7 +18,7 @@ export default class AiAssistantCardPickerUsage extends Component {
   cardIds: TrackedArray<string> = new TrackedArray([]);
   @tracked maxNumberOfCards: number | undefined = undefined;
   @tracked autoAttachedCardIds?: TrackedSet<string> = new TrackedSet();
-  @tracked autoAttachedFile?: FileDef | undefined;
+  @tracked autoAttachedFiles?: FileDef[];
   @tracked filesToAttach: TrackedArray<FileDef> = new TrackedArray([]);
 
   @action chooseCard(cardId: string) {
@@ -60,7 +60,7 @@ export default class AiAssistantCardPickerUsage extends Component {
           @removeCard={{this.removeCard}}
           @chooseFile={{this.chooseFile}}
           @removeFile={{this.removeFile}}
-          @autoAttachedFile={{this.autoAttachedFile}}
+          @autoAttachedFiles={{this.autoAttachedFiles}}
           @filesToAttach={{this.filesToAttach}}
           as |AttachedItems AttachButton|
         >
@@ -81,9 +81,9 @@ export default class AiAssistantCardPickerUsage extends Component {
           @value={{this.autoAttachedCardIds}}
         />
         <Args.Object
-          @name='autoAttachedFile'
-          @description='A file automatically attached to the message.'
-          @value={{this.autoAttachedFile}}
+          @name='autoAttachedFiles'
+          @description='Files automatically attached to the message.'
+          @value={{this.autoAttachedFiles}}
         />
         <Args.Object
           @name='filesToAttach'
diff --git a/packages/host/app/components/matrix/room.gts b/packages/host/app/components/matrix/room.gts
index d5f64b8ada..dd04f446e7 100644
--- a/packages/host/app/components/matrix/room.gts
+++ b/packages/host/app/components/matrix/room.gts
@@ -47,6 +47,7 @@ import UpdateRoomSkillsCommand from '@cardstack/host/commands/update-room-skills
 import type { Message } from '@cardstack/host/lib/matrix-classes/message';
 import type { StackItem } from '@cardstack/host/lib/stack-item';
 import { getAutoAttachment } from '@cardstack/host/resources/auto-attached-card';
+import { isReady } from '@cardstack/host/resources/file';
 import type { RoomResource } from '@cardstack/host/resources/room';
 
 import type AiAssistantPanelService from '@cardstack/host/services/ai-assistant-panel-service';
@@ -194,7 +195,7 @@ export default class Room extends Component<Signature> {
             @removeCard={{this.removeCard}}
             @chooseFile={{this.chooseFile}}
             @removeFile={{this.removeFile}}
-            @autoAttachedFile={{this.autoAttachedFile}}
+            @autoAttachedFiles={{this.autoAttachedFiles}}
             @filesToAttach={{this.filesToAttach}}
             @autoAttachedCardTooltipMessage={{if
               (eq this.operatorModeStateService.state.submode Submodes.Code)
@@ -450,7 +451,7 @@ export default class Room extends Component<Signature> {
     submode: () => this.operatorModeStateService.state.submode,
     moduleInspectorPanel: () =>
       this.operatorModeStateService.moduleInspectorPanel,
-    autoAttachedFileUrl: () => this.autoAttachedFileUrl,
+    autoAttachedFileUrls: () => this.autoAttachedFileUrls,
     playgroundPanelCardId: () => this.playgroundPanelCardId,
     activeSpecId: () => this.specPanelService.specSelection,
     topMostStackItems: () => this.topMostStackItems,
@@ -459,7 +460,7 @@ export default class Room extends Component<Signature> {
   });
   private removedAttachedCardIds = new TrackedArray<string>();
   private removedAttachedFileUrls: string[] = [];
-  private lastAutoAttachedFileUrl: string | undefined;
+  private lastAutoAttachedFileUrlsKey: string | undefined;
   private getConversationScrollability: (() => boolean) | undefined;
   private scrollConversationToBottom: (() => void) | undefined;
   private roomScrollState: WeakMap<
@@ -530,59 +531,98 @@ export default class Room extends Component<Signature> {
   // when the user opens a different file and then returns to this one.
   @use private autoAttachedFileResource = resource(() => {
     let state = new TrackedObject<{
-      value: FileDef | undefined;
-      remove: () => void;
+      value: FileDef[];
+      remove: (sourceUrl?: string) => void;
     }>({
-      value: undefined,
-      remove: () => {
-        state.value = undefined;
+      value: [],
+      remove: (sourceUrl?: string) => {
+        if (!sourceUrl) {
+          state.value = [];
+          return;
+        }
+        state.value = state.value.filter(
+          (file) => file.sourceUrl !== sourceUrl,
+        );
       },
     });
 
-    let autoAttachedFileUrl = this.autoAttachedFileUrl;
+    let autoAttachedFileUrls = this.autoAttachedFileUrls;
     let manuallyAttachedFiles = this.filesToAttach;
+    let autoAttachedFileUrlsKey = autoAttachedFileUrls.join('\n');
 
     let removedFileUrls: string[];
-    if (autoAttachedFileUrl !== this.lastAutoAttachedFileUrl) {
+    if (autoAttachedFileUrlsKey !== this.lastAutoAttachedFileUrlsKey) {
       this.removedAttachedFileUrls.splice(0);
       removedFileUrls = this.removedAttachedFileUrls;
-      this.lastAutoAttachedFileUrl = autoAttachedFileUrl;
+      this.lastAutoAttachedFileUrlsKey = autoAttachedFileUrlsKey;
     } else {
       removedFileUrls = this.removedAttachedFileUrls;
     }
 
-    let isManuallyAttached = manuallyAttachedFiles.some(
-      (file) => file.sourceUrl === autoAttachedFileUrl,
-    );
-    let isRemoved = autoAttachedFileUrl
-      ? removedFileUrls.includes(autoAttachedFileUrl)
-      : false;
+    let candidateUrls = autoAttachedFileUrls.filter((url) => {
+      if (!url) {
+        return false;
+      }
+      let isManuallyAttached = manuallyAttachedFiles.some(
+        (file) => file.sourceUrl === url,
+      );
+      let isRemoved = removedFileUrls.includes(url);
+      return !isManuallyAttached && !isRemoved;
+    });
 
-    if (!autoAttachedFileUrl || isManuallyAttached || isRemoved) {
-      state.value = undefined;
-    } else {
-      state.value = this.matrixService.fileAPI.createFileDef({
-        sourceUrl: autoAttachedFileUrl,
-        name: autoAttachedFileUrl.split('/').pop(),
-      });
-    }
+    state.value = candidateUrls.map((url) =>
+      this.matrixService.fileAPI.createFileDef({
+        sourceUrl: url,
+        name: url.split('/').pop(),
+      }),
+    );
 
     return state;
   });
 
-  private get autoAttachedFileUrl() {
-    return this.operatorModeStateService.state.codePath?.href;
+  private get autoAttachedFileUrls() {
+    let codePathUrl = this.operatorModeStateService.state.codePath?.href;
+    if (!codePathUrl) {
+      return [];
+    }
+
+    let urls = [codePathUrl];
+
+    if (codePathUrl.endsWith('.json')) {
+      let openFile = this.operatorModeStateService.openFile?.current;
+      if (openFile && isReady(openFile)) {
+        try {
+          let fileContent = JSON.parse(openFile.content);
+          let adoptsFrom = fileContent?.data?.meta?.adoptsFrom;
+          if (adoptsFrom?.module) {
+            let moduleURLWithExtension = new URL(
+              adoptsFrom.module.endsWith('.gts')
+                ? adoptsFrom.module
+                : `${adoptsFrom.module}.gts`,
+              openFile.url,
+            );
+            if (!urls.includes(moduleURLWithExtension.href)) {
+              urls.push(moduleURLWithExtension.href);
+            }
+          }
+        } catch (_error) {
+          // If JSON parse fails, fall back to just the current file URL.
+        }
+      }
+    }
+
+    return urls;
   }
 
-  private get autoAttachedFile() {
+  private get autoAttachedFiles() {
     return this.operatorModeStateService.state.submode === Submodes.Code
       ? this.autoAttachedFileResource.value
-      : undefined;
+      : [];
   }
 
   private get removeAutoAttachedFile() {
-    return () => {
-      this.autoAttachedFileResource.remove();
+    return (sourceUrl?: string) => {
+      this.autoAttachedFileResource.remove(sourceUrl);
     };
   }
 
@@ -939,8 +979,8 @@ export default class Room extends Component<Signature> {
     }
 
     let files = [];
-    if (this.autoAttachedFile) {
-      files.push(this.autoAttachedFile);
+    if (this.autoAttachedFiles.length > 0) {
+      files.push(...this.autoAttachedFiles);
     }
     files.push(...this.filesToAttach);
 
@@ -996,7 +1036,7 @@ export default class Room extends Component<Signature> {
   private chooseFile(file: FileDef) {
     // handle the case where auto-attached file pill is clicked
     if (this.isAutoAttachedFile(file)) {
-      this.removeAutoAttachedFile();
+      this.removeAutoAttachedFile(file.sourceUrl ?? undefined);
     }
 
     let files = this.filesToAttach;
@@ -1007,13 +1047,15 @@ export default class Room extends Component<Signature> {
 
   @action
   private isAutoAttachedFile(file: FileDef) {
-    return this.autoAttachedFile?.sourceUrl === file.sourceUrl;
+    return this.autoAttachedFiles.some(
+      (autoFile) => autoFile.sourceUrl === file.sourceUrl,
+    );
   }
 
   @action
   private removeFile(file: FileDef) {
     if (this.isAutoAttachedFile(file)) {
-      this.removeAutoAttachedFile();
+      this.removeAutoAttachedFile(file.sourceUrl ?? undefined);
       return;
     }
 
@@ -1228,7 +1270,7 @@ export default class Room extends Component<Signature> {
     return (
       this.filesToAttach?.length ||
       this.cardIdsToAttach?.length ||
-      this.autoAttachedFile ||
+      this.autoAttachedFiles.length > 0 ||
       this.autoAttachedCardIds?.size
     );
   }
diff --git a/packages/host/app/resources/auto-attached-card.ts b/packages/host/app/resources/auto-attached-card.ts
index 505d0c48e5..8f89bda042 100644
--- a/packages/host/app/resources/auto-attached-card.ts
+++ b/packages/host/app/resources/auto-attached-card.ts
@@ -23,7 +23,7 @@ interface Args {
   named: {
     submode: Submode;
     moduleInspectorPanel: string | undefined; // 'preview' | 'spec' | 'schema' | 'card-renderer'
-    autoAttachedFileUrl: string | undefined;
+    autoAttachedFileUrls: string[] | undefined;
     playgroundPanelCardId: string | undefined;
     activeSpecId: string | null | undefined; // selected spec card ID from SpecPanelService
     topMostStackItems: StackItem[];
@@ -45,7 +45,7 @@ export class AutoAttachment extends Resource<Args> {
     const {
       submode,
       moduleInspectorPanel,
-      autoAttachedFileUrl,
+      autoAttachedFileUrls,
       playgroundPanelCardId,
       activeSpecId,
       topMostStackItems,
@@ -55,7 +55,7 @@ export class AutoAttachment extends Resource<Args> {
     this.calculateAutoAttachments.perform(
       submode,
       moduleInspectorPanel,
-      autoAttachedFileUrl,
+      autoAttachedFileUrls,
       playgroundPanelCardId,
       activeSpecId,
       topMostStackItems,
@@ -68,7 +68,7 @@ export class AutoAttachment extends Resource<Args> {
     async (
       submode: Submode,
       moduleInspectorPanel: string | undefined,
-      autoAttachedFileUrl: string | undefined,
+      autoAttachedFileUrls: string[] | undefined,
       playgroundPanelCardId: string | undefined,
       activeSpecId: string | null | undefined,
       topMostStackItems: StackItem[],
@@ -97,8 +97,11 @@ export class AutoAttachment extends Resource<Args> {
           this.cardIds.add(item.id);
         }
       } else if (submode === Submodes.Code) {
-        let cardId = autoAttachedFileUrl?.endsWith('.json')
-          ? autoAttachedFileUrl?.replace(/\.json$/, '')
+        let cardFileUrl = autoAttachedFileUrls?.find((url) =>
+          url.endsWith('.json'),
+        );
+        let cardId = cardFileUrl
+          ? cardFileUrl.replace(/\.json$/, '')
           : undefined;
         if (
           cardId &&
@@ -133,7 +136,7 @@ export function getAutoAttachment(
   args: {
     submode: () => Submode;
     moduleInspectorPanel: () => string | undefined;
-    autoAttachedFileUrl: () => string | undefined;
+    autoAttachedFileUrls: () => string[] | undefined;
     playgroundPanelCardId: () => string | undefined;
     activeSpecId: () => string | null | undefined;
     topMostStackItems: () => StackItem[];
@@ -145,7 +148,7 @@ export function getAutoAttachment(
     named: {
       submode: args.submode(),
       moduleInspectorPanel: args.moduleInspectorPanel(),
-      autoAttachedFileUrl: args.autoAttachedFileUrl(),
+      autoAttachedFileUrls: args.autoAttachedFileUrls(),
       playgroundPanelCardId: args.playgroundPanelCardId(),
       activeSpecId: args.activeSpecId(),
       topMostStackItems: args.topMostStackItems(),
diff --git a/packages/host/tests/acceptance/ai-assistant-test.gts b/packages/host/tests/acceptance/ai-assistant-test.gts
index b2e3c43253..6eaa0dbe2b 100644
--- a/packages/host/tests/acceptance/ai-assistant-test.gts
+++ b/packages/host/tests/acceptance/ai-assistant-test.gts
@@ -1278,7 +1278,17 @@ module('Acceptance | AI Assistant tests', function (hooks) {
     await click('[data-test-file="Person/fadhlan.json"]');
     assert.dom('[data-test-attached-card]').exists({ count: 2 });
     assert.dom('[data-test-autoattached-card]').exists({ count: 1 });
-    assert.dom('[data-test-autoattached-file]').exists({ count: 1 });
+    assert.dom('[data-test-autoattached-file]').exists({ count: 2 });
+    assert
+      .dom(
+        `[data-test-attached-file="${testRealmURL}Person/fadhlan.json"][data-test-autoattached-file]`,
+      )
+      .exists();
+    assert
+      .dom(
+        `[data-test-attached-file="${testRealmURL}person.gts"][data-test-autoattached-file]`,
+      )
+      .exists();
     assert.dom(`[data-test-attached-card="${testRealmURL}Pet/mango"]`).exists();
     assert
       .dom(
diff --git a/packages/matrix/tests/messages.spec.ts b/packages/matrix/tests/messages.spec.ts
index 50e61a05aa..84ca57e62f 100644
--- a/packages/matrix/tests/messages.spec.ts
+++ b/packages/matrix/tests/messages.spec.ts
@@ -295,7 +295,10 @@ test.describe('Room messages', () => {
       .click();
     await page.locator(`[data-test-boxel-menu-item-text="Code"]`).click();
 
-    await expect(page.locator(`[data-test-attached-file]`)).toHaveCount(1);
+    await expect(page.locator(`[data-test-attached-file]`)).toHaveCount(2);
+    await expect(
+      page.locator(`[data-test-attached-file="${appURL}/person.gts"]`),
+    ).toHaveCount(1);
     await expect(
       page.locator(`[data-test-attached-file="${appURL}/hassan.json"]`),
     ).toHaveCount(1);
@@ -357,6 +360,9 @@ test.describe('Room messages', () => {
       page.locator(`[data-test-attached-card="${appURL}/hassan"]`),
     ).toHaveCount(1);
     await expect(page.locator(`[data-test-attached-file]`)).toHaveCount(1);
+    await expect(
+      page.locator(`[data-test-attached-file="${appURL}/person.gts"]`),
+    ).toHaveCount(1);
     await expect(
       page.locator(`[data-test-attached-file="${appURL}/hassan.json"]`),
     ).toHaveCount(1);