Update ADK doc according to issue #1438 - 5 Add documentation for ExecuteBashTool - merge

docs/tools/built-in-tools/bash.md

@@ -0,0 +1,37 @@
+# Bash Tool
+
+The `ExecuteBashTool` allows an agent to execute bash commands within a local workspace directory. This tool is useful for file system operations, running scripts, or interacting with the local environment.
+
+## Usage
+
+To use the Bash tool, instantiate `ExecuteBashTool` and add it to your agent's tools.
+
+```python
+from google.adk.tools.bash_tool import ExecuteBashTool, BashToolPolicy
+from google.adk.agents import LlmAgent
+
+# Create the tool with a policy
+bash_tool = ExecuteBashTool(
+    workspace="/path/to/workspace", # Defaults to current working directory
+    policy=BashToolPolicy(allowed_command_prefixes=("ls", "cat", "grep")) # Whitelist commands
+)
+
+agent = LlmAgent(
+    name="system_helper",
+    model="gemini-2.0-flash",
+    tools=[bash_tool],
+    instruction="You can execute bash commands to help the user."
+)
+```
+
+## Security
+
+The `ExecuteBashTool` includes several security features:
+
+1.  **Prefix Policy:** You can restrict which commands are allowed using `BashToolPolicy(allowed_command_prefixes=...)`. By default, all commands are allowed (`("*",)`).
+2.  **User Confirmation:** The tool **always** requests user confirmation before executing a command. The framework will pause execution and wait for the user (or client application) to approve the command via the `adk_request_confirmation` flow.
+
+## Configuration
+
+*   **`workspace`** (`pathlib.Path | None`): The directory where commands will be executed. Defaults to the current working directory.
+*   **`policy`** (`BashToolPolicy | None`): Configuration for allowed command prefixes.