tech-debt(constants): replace asyncio.sleep() magic numbers with TimingConstants (#3549) (#3556)

Adds YIELD_INTERVAL, FAST_POLL_INTERVAL, DEBOUNCE_INTERVAL_S, and
SESSION_CLEANUP_INTERVAL to TimingConstants. Migrates 29 production files
off raw float/int literals in asyncio.sleep() calls. Excludes asyncio.sleep(0)
yields (semantically must be 0), computed expressions, and test files.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: mrveiss

autobot-backend/agents/base_agent.py

@@ -18,6 +18,7 @@
 from typing import Any, Dict, List, Optional
 
 # Import communication protocol
+from constants.threshold_constants import TimingConstants
 from protocols.agent_communication import (
     AgentIdentity,
     MessageHeader,
@@ -223,7 +224,7 @@ async def health_check(self) -> AgentHealth:
 
     async def _ping(self) -> bool:
         """Basic connectivity test - can be overridden by subclasses"""
-        await asyncio.sleep(0.001)  # Simulate minimal processing
+        await asyncio.sleep(TimingConstants.YIELD_INTERVAL)  # Simulate minimal processing
         return True
 
     async def _get_resource_usage(self) -> Dict[str, Any]:

autobot-backend/ai_hardware_accelerator.py

@@ -854,7 +854,7 @@ async def _gpu_semantic_search(self, input_data: Dict[str, Any]) -> Dict[str, An
     async def _process_on_cpu(self, task: ProcessingTask) -> Dict[str, Any]:
         """Process task on CPU (fallback)."""
         # Basic CPU processing fallback
-        await asyncio.sleep(0.1)  # Simulate processing
+        await asyncio.sleep(TimingConstants.MICRO_DELAY)  # Simulate processing
 
         return {
             "result": f"CPU processed task {task.task_type}",

autobot-backend/api/codebase_analytics/indexing_phases.py

@@ -19,6 +19,8 @@
 import logging
 from typing import Callable, Optional
 
+from constants.threshold_constants import TimingConstants
+
 from .chromadb_storage import (
     _initialize_chromadb_collection,
     _prepare_batch_data,
@@ -73,7 +75,7 @@ async def _init_chromadb_with_retry(
     )
     if not code_collection:
         logger.warning("[Task %s] ChromaDB init failed, retrying once (#1249)", task_id)
-        await asyncio.sleep(2)
+        await asyncio.sleep(TimingConstants.SERVICE_STARTUP_DELAY)
         code_collection = await _initialize_chromadb_collection(
             task_id, update_progress, update_phase, source_id=source_id
         )

autobot-backend/api/log_forwarding.py

@@ -28,6 +28,7 @@
 from auth_middleware import check_admin_permission
 from autobot_shared.error_boundaries import ErrorCategory, with_error_handling
 from autobot_shared.ssot_config import config
+from constants.threshold_constants import TimingConstants
 
 # Add scripts path for log forwarder import
 sys.path.insert(0, str(Path(__file__).parent.parent.parent))
@@ -607,7 +608,7 @@ async def start_forwarding(
         thread.start()
 
         # Wait briefly for startup
-        await asyncio.sleep(0.5)
+        await asyncio.sleep(TimingConstants.SHORT_DELAY)
 
         return {"message": "Log forwarding service started"}
     except Exception as e:

autobot-backend/api/long_running_operations.py

@@ -437,7 +437,7 @@ async def migrate_existing_operation(
         async def migrated_operation(context):
             """Placeholder for migrated operation"""
             await context.update_progress("Migration placeholder", 0, 1)
-            await asyncio.sleep(1)  # Simulate work
+            await asyncio.sleep(TimingConstants.STANDARD_DELAY)  # Simulate work
             await context.update_progress("Completed", 1, 1)
             return {"status": "migrated", "original_timeout": timeout_seconds}
 

autobot-backend/api/monitoring.py

@@ -48,6 +48,7 @@
 
 # Issue #474: Import ServiceURLs for AlertManager integration
 from constants.network_constants import ServiceURLs
+from constants.threshold_constants import TimingConstants
 from type_defs.common import Metadata
 from utils.performance_monitor import (
     add_alert_callback,
@@ -1137,7 +1138,7 @@ async def test_performance_monitoring(
 ):
     """Test endpoint to demonstrate performance monitoring. Issue #744: Requires admin authentication."""
     # Simulate some work
-    await asyncio.sleep(0.1)
+    await asyncio.sleep(TimingConstants.MICRO_DELAY)
 
     # Collect current metrics
     metrics = await collect_metrics()

autobot-backend/api/process_management.py

@@ -17,6 +17,7 @@
 from pydantic import BaseModel, Field
 
 from auth_middleware import get_current_user
+from constants.threshold_constants import TimingConstants
 from services.process_adapter_service import ProcessAdapterService
 
 logger = logging.getLogger(__name__)
@@ -201,7 +202,7 @@ async def stream_process_logs(
             ):
                 await websocket.send_json({"done": True, "status": data["status"]})
                 break
-            await asyncio.sleep(0.5)
+            await asyncio.sleep(TimingConstants.SHORT_DELAY)
     except Exception:
         pass
     finally:

autobot-backend/api/terminal_websocket.py

@@ -13,6 +13,7 @@
 from starlette.websockets import WebSocketState
 
 from agents.system_command_agent import SystemCommandAgent
+from constants.threshold_constants import TimingConstants
 from event_manager import event_manager
 from services.terminal_completion_service import TerminalCompletionService
 from services.terminal_history_service import TerminalHistoryService
@@ -399,7 +400,7 @@ async def _subscribe_to_terminal_events(self, chat_id: str, websocket: WebSocket
         # Keep the subscription alive
         try:
             while chat_id in self.active_connections:
-                await asyncio.sleep(1)
+                await asyncio.sleep(TimingConstants.STANDARD_DELAY)
         finally:
             # Unsubscribe all handlers
             for event_type, handler in handlers.items():

autobot-backend/api/vnc_manager.py

@@ -532,7 +532,7 @@ async def vnc_mouse_drag(
     for x, y in path_points[1:]:  # Skip first point (already there)
         _run_xdotool_cmd(["mousemove", str(x), str(y)])
         # Small delay between movements for smooth curve
-        await asyncio.sleep(0.01)
+        await asyncio.sleep(TimingConstants.POLL_INTERVAL)
 
     # Release mouse button at end position
     return _run_xdotool_cmd(["mouseup", "1"])

autobot-backend/constants/threshold_constants.py

@@ -112,10 +112,15 @@ class KnowledgeSyncConfig:
 class TimingConstants:
     """Common timing values used throughout the codebase."""
 
+    # Sub-millisecond yields (asyncio.sleep)
+    YIELD_INTERVAL = 0.001  # Brief yield to event loop between batches
+
     # Short delays (sub-second)
     POLL_INTERVAL = 0.01  # Short polling loop delay to prevent CPU spinning
+    FAST_POLL_INTERVAL = 0.02  # Fast polling / short scan simulation delay
     STREAMING_CHUNK_DELAY = 0.05  # Delay between streaming chunks for UX
     MICRO_DELAY = 0.1
+    DEBOUNCE_INTERVAL_S = 0.2  # Debounce / short API simulation delay
     SHORT_DELAY = 0.5
     STANDARD_DELAY = 1.0
 
@@ -130,6 +135,7 @@ class TimingConstants:
     VERY_LONG_TIMEOUT = 300
 
     # Long interval values
+    SESSION_CLEANUP_INTERVAL = 60  # Background session cleanup polling interval (1 min)
     HOURLY_INTERVAL = 3600  # 1 hour in seconds
 
     # Error recovery