Live development without restarts
Modify DevDuck's code while it's running. Changes apply instantly without losing context. Protected during agent execution.
DevDuck watches its own source file and automatically reloads when changes are detected.
┌─────────────────────────────────────────────────────────────────────┐ │ Hot Reload System │ ├─────────────────────────────────────────────────────────────────────┤ │ │ │ File Watcher Thread │ │ │ │ │ ├── Every 1 second: │ │ │ └── Check devduck/__init__.py mtime │ │ │ │ │ ├── Change Detected? │ │ │ │ │ │ │ ├── Agent Executing? │ │ │ │ └── Set _reload_pending = True │ │ │ │ └── Wait for agent to finish │ │ │ │ │ │ │ └── Agent Idle? │ │ │ └── Trigger os.execv() → Full Process Restart │ │ │ │ │ └── 3 second debounce to prevent rapid reloads │ │ │ └─────────────────────────────────────────────────────────────────────┘
Hot reload never interrupts a running agent. When code changes are detected during execution:
_reload_pending flag is setCreate new tools by saving .py files to the ./tools/ directory.
# Create ./tools/my_tool.py
from strands import tool
@tool
def my_custom_tool(param: str) -> dict:
"""My custom tool description."""
return {
"status": "success",
"content": [{"text": f"Processed: {param}"}]
}
# Save the file → Tool is immediately available!
# No restart needed# Disable auto-loading tools from ./tools/ directory
export DEVDUCK_LOAD_TOOLS_FROM_DIR=false
devduckBackground thread monitors source file every second for changes.
3-second debounce prevents rapid reloads during file saves.
Never interrupts running agent—waits for completion.
Uses os.execv() for clean process restart with fresh code.
Drop .py files in ./tools/ for instant tool availability.
Check watcher status via devduck.status()["file_watcher"].
import devduck
# Check file watcher status
status = devduck.status()
print(status["file_watcher"])
# {
# "enabled": True,
# "watching": "/path/to/devduck/__init__.py"
# }
# Manually trigger hot reload
devduck.hot_reload()
# Full restart (re-initializes everything)
devduck.restart()| Variable | Default | Description |
|---|---|---|
DEVDUCK_LOAD_TOOLS_FROM_DIR |
true | Auto-load tools from ./tools/ directory |