Add CLI coding agent sample

contributing/samples/cli_coding_agent/.gitignore

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+**/__pycache__/

contributing/samples/cli_coding_agent/README.md

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+# ADK CLI Coding Agent
+
+An AI coding assistant built with Google ADK featuring file system operations, task planning, and colorful interactive CLI output.
+
+**This is a toy example! It is not meant to be a replacement for fully featured products like the Gemini CLI or Claude Code.**
+
+
+![alt text](image.png)
+
+## Features
+
+
+**File System Tools**
+- `read_file` - Read file contents with metadata
+- `write_file` - Create or overwrite files
+- `update_file` - Replace text within files
+- `list_directory` - List files/directories with glob patterns
+
+**Task Planning**
+- `create_plan` - Break down complex tasks into steps
+- `update_plan` - Mark tasks as completed
+- `get_plan` - View current plan and progress
+- `reset_plan` - Clear completed plan
+
+**Colorful Terminal UI**
+- Interactive CLI with color-coded output
+- Progress tracking with visual task lists
+- Concise/verbose output modes
+
+## Setup
+
+1. **Navigate to this sample directory:**
+   ```bash
+   cd contributing/samples/cli_coding_agent
+   ```
+
+2. **Install dependencies:**
+   ```bash
+   uv pip install -r requirements.txt
+   ```
+
+3. **Authenticate with Google Cloud:**
+   ```bash
+   gcloud auth application-default login
+   ```
+
+4. **Run the agent:**
+   ```bash
+   uv run python -m agent
+   ```
+
+   Or use ADK's built-in web interface:
+   ```bash
+   adk web agent
+   ```
+
+## Usage
+
+The agent automatically creates plans for multi-step tasks (3+ steps) and tracks progress:
+
+```
+[You]: Help me refactor this codebase
+
+📋 PLAN: Refactor Codebase
+Progress: [████████░░░░] 2/3 (67%)
+  ✓ [0] Analyze current structure
+  ✓ [1] Extract common utilities
+  ○ [2] Update imports and tests
+
+🔧 update_file(file_path=utils.py, old_text=...)
+✓ update_file
+```
+
+**Commands:**
+- `exit/quit` - Exit the assistant
+- `verbose` - Toggle verbose tool output

contributing/samples/cli_coding_agent/agent/__init__.py

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+"""Coding agent package for file system operations with ADK."""
+
+import logging
+from pathlib import Path
+import sys
+
+from dotenv import load_dotenv
+
+# Load environment variables
+load_dotenv()
+
+
+def setup_logging(
+    level=logging.INFO, log_file='coding_agent.log', quiet_adk=True
+):
+  """Configure logging for the coding agent package.
+
+  Args:
+      level: Logging level (default: INFO)
+      log_file: Path to log file (default: 'coding_agent.log')
+      quiet_adk: If True, set ADK loggers to WARNING level (default: True)
+  """
+  # Create formatters
+  detailed_formatter = logging.Formatter(
+      '%(asctime)s - %(name)s - %(levelname)s - %(message)s',
+      datefmt='%Y-%m-%d %H:%M:%S',
+  )
+
+  # Console handler (simple format)
+  console_handler = logging.StreamHandler(sys.stdout)
+  console_handler.setLevel(level)
+  console_handler.setFormatter(detailed_formatter)
+
+  # File handler (detailed format)
+  log_path = Path(log_file)
+  file_handler = logging.FileHandler(log_path)
+  file_handler.setLevel(logging.DEBUG)  # Log everything to file
+  file_handler.setFormatter(detailed_formatter)
+
+  # Configure root logger
+  root_logger = logging.getLogger()
+  root_logger.setLevel(logging.DEBUG)
+  root_logger.addHandler(console_handler)
+  root_logger.addHandler(file_handler)
+
+  # Quiet down noisy libraries
+  if quiet_adk:
+    logging.getLogger('google_adk').setLevel(logging.WARNING)
+    logging.getLogger('google.genai').setLevel(logging.WARNING)
+    logging.getLogger('google_genai.types').setLevel(logging.ERROR)
+    logging.getLogger('httpx').setLevel(logging.WARNING)
+    logging.getLogger('httpcore').setLevel(logging.WARNING)
+    logging.getLogger('google_genai.models').setLevel(logging.WARNING)
+
+  return logging.getLogger(__name__)
+
+
+# Initialize logging
+logger = setup_logging()
+logger.info('Coding agent package initialized')
+
+# Import agent after logging is configured
+from . import agent
+
+__all__ = ['agent', 'logger', 'setup_logging']