shell bones (#160)

* shell bones

* Merge remote-tracking branch 'origin/main' into shell_bones

* add line break

* another line break

* drop the log to avoid breaking terminals

* rename tool to be consistent with terminal

* fix build

4 files changed, 74 insertions, 2 deletions

diff --git a/packages/server/src/config/config.ts b/packages/server/src/config/config.ts
index 06092b84..8a49380c 100644
--- a/packages/server/src/config/config.ts
+++ b/packages/server/src/config/config.ts
@@ -15,9 +15,11 @@ import { GrepTool } from '../tools/grep.js';
 import { GlobTool } from '../tools/glob.js';
 import { EditTool } from '../tools/edit.js';
 import { TerminalTool } from '../tools/terminal.js';
+import { ShellTool } from '../tools/shell.js';
 import { WriteFileTool } from '../tools/write-file.js';
 import { WebFetchTool } from '../tools/web-fetch.js';
 import { ReadManyFilesTool } from '../tools/read-many-files.js';
+import { BaseTool, ToolResult } from '../tools/tools.js';
 
 const DEFAULT_PASSTHROUGH_COMMANDS = ['ls', 'git', 'npm'];
 
@@ -132,17 +134,24 @@ function createToolRegistry(config: Config): ToolRegistry {
   const registry = new ToolRegistry();
   const targetDir = config.getTargetDir();
 
-  const tools = [
+  const tools: Array<BaseTool<unknown, ToolResult>> = [
     new LSTool(targetDir),
     new ReadFileTool(targetDir),
     new GrepTool(targetDir),
     new GlobTool(targetDir),
     new EditTool(targetDir),
-    new TerminalTool(targetDir, config),
     new WriteFileTool(targetDir),
     new WebFetchTool(), // Note: WebFetchTool takes no arguments
     new ReadManyFilesTool(targetDir),
   ];
+
+  // use ShellTool (next-gen TerminalTool) if environment variable is set
+  if (process.env.SHELL_TOOL) {
+    tools.push(new ShellTool(targetDir, config));
+  } else {
+    tools.push(new TerminalTool(targetDir, config));
+  }
+
   for (const tool of tools) {
     registry.registerTool(tool);
   }
diff --git a/packages/server/src/tools/shell.json b/packages/server/src/tools/shell.json
new file mode 100644
index 00000000..f1ba372e
--- /dev/null
+++ b/packages/server/src/tools/shell.json
@@ -0,0 +1,18 @@
+{
+  "type": "object",
+  "properties": {
+    "command": {
+      "description": "The exact bash command or sequence of commands (using ';' or '&&') to execute. Must adhere to usage guidelines. Example: 'npm install && npm run build'",
+      "type": "string"
+    },
+    "description": {
+      "description": "Optional: A brief, user-centric explanation of what the command does and why it's being run. Used for logging and confirmation prompts. Example: 'Install project dependencies'",
+      "type": "string"
+    },
+    "runInBackground": {
+      "description": "If true, execute the command in the background using '&'. Defaults to false. Use for servers or long tasks.",
+      "type": "boolean"
+    }
+  },
+  "required": ["command"]
+}
diff --git a/packages/server/src/tools/shell.md b/packages/server/src/tools/shell.md
new file mode 100644
index 00000000..ce71e42c
--- /dev/null
+++ b/packages/server/src/tools/shell.md
@@ -0,0 +1 @@
+This is a minimal shell tool.
diff --git a/packages/server/src/tools/shell.ts b/packages/server/src/tools/shell.ts
new file mode 100644
index 00000000..658293b0
--- /dev/null
+++ b/packages/server/src/tools/shell.ts
@@ -0,0 +1,44 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import path from 'path';
+import fs from 'fs';
+import { Config } from '../config/config.js';
+import { BaseTool, ToolResult } from './tools.js';
+
+export interface ShellToolParams {
+  command: string;
+  description?: string;
+}
+
+export class ShellTool extends BaseTool<ShellToolParams, ToolResult> {
+  static Name: string = 'execute_bash_command';
+  private readonly rootDirectory: string;
+  private readonly config: Config;
+
+  constructor(rootDirectory: string, config: Config) {
+    const toolDisplayName = 'Shell';
+    const descriptionUrl = new URL('shell.md', import.meta.url);
+    const toolDescription = fs.readFileSync(descriptionUrl, 'utf-8');
+    const schemaUrl = new URL('shell.json', import.meta.url);
+    const toolParameterSchema = JSON.parse(fs.readFileSync(schemaUrl, 'utf-8'));
+    super(
+      ShellTool.Name,
+      toolDisplayName,
+      toolDescription,
+      toolParameterSchema,
+    );
+    this.config = config;
+    this.rootDirectory = path.resolve(rootDirectory);
+  }
+
+  async execute(_params: ShellToolParams): Promise<ToolResult> {
+    return {
+      llmContent: 'hello',
+      returnDisplay: 'hello',
+    };
+  }
+}