Docs: Add initial project documentation structure and content (#368)

Co-authored-by: Taylor Mullen <ntaylormullen@google.com>

docs/tools/shell.md

@@ -0,0 +1,40 @@
+# Shell Tool
+
+This document provides details on the shell tool available.
+
+## `execute_bash_command`
+
+- **Purpose:** Executes a given shell command using `bash -c <command>`. This tool is essential for interacting with the underlying operating system, running scripts, or performing command-line operations.
+- **Arguments:**
+  - `command` (string, required): The exact bash command to execute.
+  - `description` (string, optional): A brief description of the command's purpose, which will be shown to the user.
+  - `directory` (string, optional): The directory (relative to the project root) in which to execute the command. If not provided, the command runs in the project root.
+- **Behavior:**
+  - The command is executed as a subprocess.
+  - It can start background processes using `&`.
+  - The tool returns detailed information about the execution, including:
+    - `Command`: The command that was executed.
+    - `Directory`: The directory where the command was run.
+    - `Stdout`: Output from the standard output stream.
+    - `Stderr`: Output from the standard error stream.
+    - `Error`: Any error message reported by the subprocess.
+    - `Exit Code`: The exit code of the command.
+    - `Signal`: The signal number if the command was terminated by a signal.
+    - `Background PIDs`: A list of PIDs for any background processes started.
+- **Examples:**
+  - Listing files in the current directory:
+    ```
+    execute_bash_command(command="ls -la")
+    ```
+  - Running a script in a specific directory:
+    ```
+    execute_bash_command(command="./my_script.sh", directory="scripts", description="Run my custom script")
+    ```
+  - Starting a background server:
+    ```
+    execute_bash_command(command="npm run dev &", description="Start development server in background")
+    ```
+- **Important Notes:**
+  - **Security:** Be cautious when executing commands, especially those constructed from user input, to prevent security vulnerabilities.
+  - **Interactive Commands:** Avoid commands that require interactive user input, as this can cause the tool to hang. Use non-interactive flags if available (e.g., `npm init -y`).
+  - **Error Handling:** Check the `Stderr`, `Error`, and `Exit Code` fields to determine if a command executed successfully.