diff --git a/packages/jupyter-ai/src/chat-command-plugins/index.ts b/packages/jupyter-ai/src/chat-command-plugins/index.ts
index ba996f62b..ca4b5988c 100644
--- a/packages/jupyter-ai/src/chat-command-plugins/index.ts
+++ b/packages/jupyter-ai/src/chat-command-plugins/index.ts
@@ -1,4 +1,9 @@
 import { fileCommandPlugin } from './file-command';
 import { slashCommandPlugin } from './slash-commands';
+import { selectionCommandPlugin } from './text-command';
 
-export const chatCommandPlugins = [fileCommandPlugin, slashCommandPlugin];
+export const chatCommandPlugins = [
+  fileCommandPlugin,
+  slashCommandPlugin,
+  selectionCommandPlugin
+];
diff --git a/packages/jupyter-ai/src/chat-command-plugins/text-command.tsx b/packages/jupyter-ai/src/chat-command-plugins/text-command.tsx
new file mode 100644
index 000000000..1991d9791
--- /dev/null
+++ b/packages/jupyter-ai/src/chat-command-plugins/text-command.tsx
@@ -0,0 +1,205 @@
+/*
+ * Copyright (c) Jupyter Development Team.
+ * Distributed under the terms of the Modified BSD License.
+ */
+
+import React from 'react';
+import { JupyterFrontEndPlugin } from '@jupyterlab/application';
+import { INotebookTracker } from '@jupyterlab/notebook';
+import {
+  IChatCommandProvider,
+  IChatCommandRegistry,
+  IInputModel,
+  ChatCommand
+} from '@jupyter/chat';
+import TextFieldsIcon from '@mui/icons-material/TextFields';
+
+const SELECTION_COMMAND_PROVIDER_ID =
+  '@jupyter-ai/core:selection-command-provider';
+
+/**
+ * A command provider that provides completions for `@selection` commands and handles
+ * `@selection` command calls.
+ */
+export class SelectionCommandProvider implements IChatCommandProvider {
+  public id: string = SELECTION_COMMAND_PROVIDER_ID;
+
+  constructor(
+    private shell: any,
+    private notebookTracker: INotebookTracker
+  ) {}
+
+  /**
+   * Regex that matches all potential `@selection` commands.
+   */
+  _regex: RegExp = /@selection/g;
+
+  async listCommandCompletions(
+    inputModel: IInputModel
+  ): Promise<ChatCommand[]> {
+    // do nothing if the current word does not start with '@'.
+    const currentWord = inputModel.currentWord;
+    if (!currentWord || !currentWord.startsWith('@')) {
+      return [];
+    }
+
+    // Check if any selection is available (prefer text selection, fallback to active cell)
+    const hasTextSelection = !!inputModel.selectionWatcher?.selection;
+    const hasActiveCell = inputModel.activeCellManager?.available;
+
+    // Don't show @selection if no options are available
+    if (!hasTextSelection && !hasActiveCell) {
+      return [];
+    }
+
+    // if the current word matches the start of @selection, complete it
+    if ('@selection'.startsWith(currentWord)) {
+      const description = hasTextSelection
+        ? 'Include selected text'
+        : 'Include active cell content';
+
+      return [
+        {
+          name: '@selection',
+          providerId: this.id,
+          description,
+          icon: <TextFieldsIcon />,
+          replaceWith: '@selection',
+          spaceOnAccept: true
+        }
+      ];
+    }
+
+    // otherwise, return nothing as this provider cannot provide any completions
+    // for the current word.
+    return [];
+  }
+
+  async onSubmit(inputModel: IInputModel): Promise<void> {
+    // Check if the input contains @selection
+    if (!this._regex.test(inputModel.value)) {
+      return;
+    }
+
+    // Get the current widget from the shell
+    const currentWidget = this.shell.currentWidget;
+    if (!currentWidget) {
+      return;
+    }
+
+    // Get the document context to access the path
+    const documentManager = inputModel.documentManager;
+    if (!documentManager) {
+      return;
+    }
+
+    const context = documentManager.contextForWidget(currentWidget as any);
+    if (!context) {
+      return;
+    }
+
+    const path = context.path;
+
+    // Prefer text selection, fallback to active cell
+    const selection = inputModel.selectionWatcher?.selection;
+    const activeCellManager = inputModel.activeCellManager;
+
+    if (selection && selection.text.trim().length > 0) {
+      // Text selection with actual content - create attachment with selection range
+      if (path.endsWith('.ipynb') && selection.cellId) {
+        // Notebook with cell selection - get the cell type from the active cell
+        const notebook = this.notebookTracker.currentWidget;
+        if (!notebook) {
+          return;
+        }
+
+        // Find the cell by ID to get its type
+        const cell = notebook.content.widgets.find(
+          c => c.model.id === selection.cellId
+        );
+        const cellType = cell?.model.type ?? 'code';
+        const inputType =
+          cellType === 'code'
+            ? 'code'
+            : cellType === 'markdown'
+              ? 'markdown'
+              : 'raw';
+
+        inputModel.addAttachment?.({
+          type: 'notebook',
+          value: path,
+          cells: [
+            {
+              id: selection.cellId,
+              input_type: inputType,
+              selection: {
+                start: [selection.start.line, selection.start.column],
+                end: [selection.end.line, selection.end.column],
+                content: selection.text
+              }
+            }
+          ]
+        });
+      } else {
+        // Regular file with selection
+        inputModel.addAttachment?.({
+          type: 'file',
+          value: path,
+          selection: {
+            start: [selection.start.line, selection.start.column],
+            end: [selection.end.line, selection.end.column],
+            content: selection.text
+          }
+        });
+      }
+    } else if (activeCellManager?.available && path.endsWith('.ipynb')) {
+      // No meaningful text selection, but active cell is available in notebook
+      const notebook = this.notebookTracker.currentWidget;
+      if (!notebook) {
+        return;
+      }
+
+      const activeCell = notebook.content.activeCell;
+      if (!activeCell) {
+        return;
+      }
+
+      // Get cell ID and type
+      const cellId = activeCell.model.id;
+      const cellType = activeCell.model.type;
+      const inputType =
+        cellType === 'code' ? 'code' : cellType === 'markdown' ? 'markdown' : 'raw';
+
+      // Attach the specific cell without selection range
+      inputModel.addAttachment?.({
+        type: 'notebook',
+        value: path,
+        cells: [
+          {
+            id: cellId,
+            input_type: inputType
+          }
+        ]
+      });
+    }
+
+    return;
+  }
+}
+
+export const selectionCommandPlugin: JupyterFrontEndPlugin<void> = {
+  id: '@jupyter-ai/core:selection-command-plugin',
+  description: 'Adds support for the @selection command in Jupyter AI.',
+  autoStart: true,
+  requires: [IChatCommandRegistry],
+  optional: [INotebookTracker],
+  activate: (
+    app,
+    registry: IChatCommandRegistry,
+    notebookTracker: INotebookTracker | null
+  ) => {
+    registry.addProvider(
+      new SelectionCommandProvider(app.shell, notebookTracker!)
+    );
+  }
+};