manual_slop/conductor/tracks/pipeline_pause_resume_20260306/spec.md

Track Specification: Pipeline Pause/Resume (pipeline_pause_resume_20260306)

Overview

Add global pause/resume for entire DAG execution pipeline. Allow user to freeze all worker activity and resume later without losing state.

Current State Audit

Already Implemented (DO NOT re-implement)

Execution Loop (multi_agent_conductor.py)

• ConductorEngine.run(): Async loop that processes tickets
• Loop continues until: All complete OR all blocked OR error
• No pause mechanism

Execution Engine (dag_engine.py)

• ExecutionEngine.tick(): Returns ready tasks
• auto_queue flag: Controls automatic task promotion
• No global pause state

GUI State (gui_2.py)

• mma_status: "idle" | "planning" | "executing" | "done"
• No paused state

Gaps to Fill (This Track's Scope)

• No way to pause execution mid-pipeline
• No way to resume from paused state
• No visual indicator for paused state

Architectural Constraints

State Preservation

• Running workers MUST complete before pause takes effect
• Paused state MUST preserve all ticket statuses
• No data loss on resume

Atomic Operation

• Pause MUST be atomic (all-or-nothing)
• No partial pause state

Non-Blocking

• Pause request MUST NOT block GUI thread
• Pause signaled via threading.Event

Architecture Reference

Key Integration Points

File	Lines	Purpose
src/multi_agent_conductor.py	80-150	ConductorEngine.run() - add pause check
src/dag_engine.py	50-80	ExecutionEngine - add pause state
src/gui_2.py	~170	State for pause flag
src/gui_2.py	2650-2750	_render_mma_dashboard() - add pause button

Proposed Pause Pattern

# In ConductorEngine:
self._pause_event: threading.Event = threading.Event()

def pause(self) -> None:
 self._pause_event.set()

def resume(self) -> None:
 self._pause_event.clear()

# In run() loop:
async def run(self):
 while True:
  if self._pause_event.is_set():
   await asyncio.sleep(0.5)  # Wait while paused
   continue
  # Normal processing...

Functional Requirements

FR1: Pause Button

• Button in MMA dashboard
• Disabled when no execution active
• Click triggers engine.pause()

FR2: Resume Button

• Button in MMA dashboard (replaces pause when paused)
• Disabled when not paused
• Click triggers engine.resume()

FR3: Visual Indicator

• Banner or icon when paused
• mma_status shows "paused"
• Ticket status preserved

FR4: State Display

• Show which workers were running when paused
• Show pending tasks that will resume

Non-Functional Requirements

Requirement	Constraint
Response Time	Pause takes effect within 500ms
No Data Loss	All state preserved
Visual Feedback	Clear paused indicator

Testing Requirements

Unit Tests

• Test pause stops task spawning
• Test resume continues from correct state
• Test state preserved across pause

Integration Tests (via live_gui fixture)

• Start execution, pause, verify workers stop
• Resume, verify execution continues
• Verify no state loss

Out of Scope

• Per-ticket pause (all-or-nothing only)
• Scheduled pause
• Pause during individual API call

Acceptance Criteria

• Pause button freezes pipeline
• Resume button continues execution
• Visual indicator shows paused state
• Worker states preserved
• No data loss on resume
• mma_status includes "paused"
• 1-space indentation maintained