1 files changed, 262 insertions, 0 deletions
diff --git a/packages/cli/src/ui/commands/backgroundCommand.ts b/packages/cli/src/ui/commands/backgroundCommand.ts
new file mode 100644
index 00000000..cbeb18df
--- /dev/null
+++ b/packages/cli/src/ui/commands/backgroundCommand.ts
@@ -0,0 +1,262 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { SlashCommand, CommandContext } from './types.js';
+import {
+  Config,
+  BackgroundAgentMessage,
+  partListUnionToString,
+} from '@google/gemini-cli-core';
+
+const MAX_STATUS_MESSAGE_LENGTH = 100;
+
+function toMessageString(message?: BackgroundAgentMessage): string {
+  return partListUnionToString(message?.parts ?? []).trim();
+}
+
+function toOneliner(input: string, maxlength: number) {
+  let output = input.replace(/\r?\n|\r/g, ' ');
+  if (output.length > maxlength) {
+    output = output.substring(0, maxlength) + '...';
+  }
+  return output;
+}
+
+function getActiveAgent(context: CommandContext) {
+  const agent =
+    context.services.config?.getBackgroundAgentManager()?.activeAgent;
+  if (!agent) {
+    throw Error('There is no active background agent.');
+  }
+  return agent;
+}
+
+function addClientHistory(context: CommandContext, text: string) {
+  context.services.config!.getGeminiClient().addHistory({
+    role: 'user',
+    parts: [{ text }],
+  });
+
+  context.services.config!.getGeminiClient().addHistory({
+    role: 'model',
+    parts: [{ text: 'Got it.' }],
+  });
+}
+
+const startSubcommand: SlashCommand = {
+  name: 'start',
+  description:
+    'Start a new task with the provided prompt. Usage: /bg start <prompt>',
+  action: async (context, args) => {
+    if (!args || args.trim() === '') {
+      return {
+        type: 'message',
+        messageType: 'error',
+        content: 'The `start` command requires a prompt.',
+      };
+    }
+
+    const agent = getActiveAgent(context);
+    const task = await agent.startTask(args);
+
+    addClientHistory(
+      context,
+      `I started a background task with id '${task.id}' and prompt:\n${args}`,
+    );
+
+    return {
+      type: 'message',
+      messageType: 'info',
+      content: `Started background task with id '${task.id}' and prompt:\n${args}`,
+    };
+  },
+};
+
+const stopSubcommand: SlashCommand = {
+  name: 'stop',
+  description: 'Stops a running task. Usage: /bg stop <task_id>',
+  action: async (context, args) => {
+    if (!args || args.trim() === '') {
+      return {
+        type: 'message',
+        messageType: 'error',
+        content: 'The `stop` command requires a task id.',
+      };
+    }
+    const agent = getActiveAgent(context);
+    await agent.cancelTask(args);
+    addClientHistory(context, `I canceled the background task with id ${args}`);
+    return {
+      type: 'message',
+      messageType: 'info',
+      content: `Stopped background task with id ${args}.`,
+    };
+  },
+};
+
+const listSubcommand: SlashCommand = {
+  name: 'list',
+  description: 'List all tasks',
+  action: async (context, args) => {
+    if (args && args.trim() !== '') {
+      return {
+        type: 'message',
+        messageType: 'error',
+        content: 'The `list` command takes no arguments.',
+      };
+    }
+
+    const agent = getActiveAgent(context);
+    const tasks = await agent.listTasks();
+    let content: string;
+    if (tasks.length === 0) {
+      content = 'No background tasks found.';
+    } else {
+      const taskList = tasks
+        .map((task) => {
+          const shortStatus = toOneliner(
+            toMessageString(task.status.message),
+            MAX_STATUS_MESSAGE_LENGTH,
+          );
+          return `  - ${task.id}: (${task.status.state}) ${shortStatus}`;
+        })
+        .join('\n');
+      content = `Background tasks:\n${taskList}`;
+    }
+    return {
+      type: 'message',
+      messageType: 'info',
+      content,
+    };
+  },
+};
+
+const getSubcommand: SlashCommand = {
+  name: 'get',
+  description: 'View a task. Usage: /bg get <task_id>',
+  action: async (context, args) => {
+    if (!args || args.trim() === '') {
+      return {
+        type: 'message',
+        messageType: 'error',
+        content: 'The `get` command requires a task id.',
+      };
+    }
+    const agent = getActiveAgent(context);
+    const task = await agent.getTask(args);
+    const content = `Task Details for ${task.id}:
+Status: (${task.status.state}) ${toMessageString(task.status.message)}}`;
+
+    return {
+      type: 'message',
+      messageType: 'info',
+      content,
+    };
+  },
+};
+
+const logsSubcommand: SlashCommand = {
+  name: 'logs',
+  description: "View a task's recent logs. Usage: /bg log <task_id>",
+  action: async (context, args) => {
+    if (!args || args.trim() === '') {
+      return {
+        type: 'message',
+        messageType: 'error',
+        content: 'The `log` command requires a task id.',
+      };
+    }
+    const agent = getActiveAgent(context);
+    const task = await agent.getTask(args, 5);
+    const contents = [
+      `Task logs for ${task.id}. status: (${task.status.state})`,
+    ];
+    (task.history ?? []).forEach((message) => {
+      contents.push(toMessageString(message));
+    });
+    return {
+      type: 'message',
+      messageType: 'info',
+      content: contents.join('\n\n'),
+    };
+  },
+};
+
+const messageSubcommand: SlashCommand = {
+  name: 'message',
+  description:
+    'Send a message to a task. Usage: /bg message <task_id> <message>',
+  action: async (context, args) => {
+    if (!args || args.trim() === '' || !args.trim().includes(' ')) {
+      return {
+        type: 'message',
+        messageType: 'error',
+        content: 'The `message` command requires a task id and a message.',
+      };
+    }
+
+    const firstSpaceIndex = args.indexOf(' ');
+    const id = args.substring(0, firstSpaceIndex);
+    const message = args.substring(firstSpaceIndex + 1);
+
+    const agent = getActiveAgent(context);
+    await agent.messageTask(id, message);
+    addClientHistory(
+      context,
+      `I sent a message to the background task with id '${id}':\n${message}`,
+    );
+
+    return {
+      type: 'message',
+      messageType: 'info',
+      content: `Sent a message to the background task with id '${id}':\n${message}`,
+    };
+  },
+};
+
+const deleteSubcommand: SlashCommand = {
+  name: 'delete',
+  description: 'Deletes a task. Usage: /bg delete <task_id>',
+  action: async (context, args) => {
+    if (!args) {
+      return {
+        type: 'message',
+        messageType: 'error',
+        content: 'The `delete` command requires a task id.',
+      };
+    }
+    const agent = getActiveAgent(context);
+    await agent.deleteTask(args);
+    addClientHistory(context, `I deleted the background task with id ${args}`);
+    return {
+      type: 'message',
+      messageType: 'info',
+      content: `Task ${args} deleted.`,
+    };
+  },
+};
+
+export const backgroundCommand = (
+  config: Config | null,
+): SlashCommand | null => {
+  if (!config?.getBackgroundAgentManager()?.activeAgent) {
+    return null;
+  }
+  return {
+    name: 'background',
+    altName: 'bg',
+    description: "Commands for managing the background agent's tasks",
+    subCommands: [
+      startSubcommand,
+      stopSubcommand,
+      listSubcommand,
+      getSubcommand,
+      logsSubcommand,
+      messageSubcommand,
+      deleteSubcommand,
+    ],
+  };
+};