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Cognitive / Multi-Agent AI System
Arc - AI Multi-Agent Planning System (Product Management AI)
Solo-built LangGraph(StateGraph) multi-agent planning system that routes across specialized agents (research/analysis/planning/critic) to turn a goal into an executable plan. Includes WebSocket streaming, DB persistence for conversations/token usage, and checkpoint-based resume.
- Role
- Solo builder · architecture, implementation, and operational tooling
- Period
- 2025 - Present
- Context
- Personal Project
Solo-built LangGraph(StateGraph) multi-agent planning system that routes across specialized agents (research/analysis/planning/critic) to turn a goal into an executable plan. Includes WebSocket streaming, DB persistence for conversations/token usage, and checkpoint-based resume.
What made the system difficult.
Needed realtime visibility into multi-step agent runs, plus reliability features like checkpoint/resume and consistent persistence across reconnects.
How boundaries and flows answered it.
Implemented StateGraph workflows and a FastAPI WebSocket endpoint that validates project ownership and streams workflow events/state sync. Added token/cost tracking backed by a pricing table and a checkpoint-driven resume flow for long-running executions.
The path of responsibility through the system.
Coordinator Agent
Workflow Orchestration
Responsibilities
- — Workflow orchestration
- — Task routing & coordination
Research Agents
Data Collection
Responsibilities
- — Web research & synthesis
- — Structured evidence gathering
Planner & Critic
Content Generation & QA
Responsibilities
- — Structured plan generation
- — Review/critique loop
Overview
- Solo-built LangGraph-based multi-agent planning system (Arc/PMAI).
Purpose & User Flow
Purpose
- Automate planning: take a goal and produce structured deliverables via agent division of labor + critique loops.
User Flow
- Input goal/context → run workflow (agent routing) → stream step-level progress and artifacts (WebSocket) → resume from checkpoints → export deliverables.
Key Components
- StateGraph workflows with conditional routing between agent roles (
backend/agents/graph.py) - FastAPI WebSocket streaming endpoint with state sync/resume (
backend/api/websocket.py) - Token/cost tracking with pricing table + provider balances (
backend/agents/token_tracker.py) - Checkpoint-based resume flow (
resume_workflow)