Work Order Management System — System Design Document

Classification: Internal — Engineering Date: 2026-02-13 Status: Proposed

1. Context Diagram

The WO Management System operates as a control plane subsystem within CODITECT. It mediates between four actor categories and four system boundaries.

Actors:

System Owners — Initiate and approve WOs for validated systems they own.
QA Personnel — Review and co-approve regulatory WOs.
IT/Operations Staff — Execute WO tasks (build workstations, configure systems).
Vendors — Execute external WO tasks (install applications, provide IQ/OQ).
CODITECT Agents — Autonomously create, execute, and transition WOs.

System Boundaries:

CODITECT Control Plane — Agent Orchestrator, Compliance Engine, Checkpoint Manager.
CODITECT Data Plane — IDE Shell (developer-facing), Agent Workers.
External Systems — Asset Management, Ticketing (ServiceNow), Vendor Portals.
Compliance Infrastructure — Audit Repository, Certificate Authority, Policy Engine.

2. Component Breakdown

2.1 WO Lifecycle Engine

Core state machine managing WO status transitions with validation, audit trail generation, and event emission.

States: draft → pending_approval → assigned → in_progress → blocked → completed → closed

Invariants:

No transition without audit entry (reason required for regulatory WOs).
completed requires all required approvals collected (System Owner + QA for regulatory).
in_progress requires all dependencies satisfied (DAG check).
blocked triggers upstream notification to Master WO agent.

2.2 WO Hierarchy Manager

Manages Master WO ↔ Linked WO relationships, dependency graphs, and progress tracking.

Responsibilities:

Create/link child WOs to Master WO.
Validate dependency DAG (no cycles).
Calculate critical path through linked WO dependency graph.
Report Master WO progress (% complete, blocked items, estimated completion).

2.3 Resource Matcher

Matches WO requirements (from Job Plans) against available resources.

Inputs: Required tools, experience levels, person count, schedule constraints. Outputs: Candidate assignment list ranked by: availability → experience rating → cost. Integration: Feeds into Agent Orchestrator's capability matching for automated assignment.

2.4 Approval Workflow Engine

Manages approval chains with electronic signature collection.

Approval types: System Owner (mandatory for regulatory), QA (mandatory for regulatory), Additional (configurable per tenant/WO type). E-signature: Hash of (approver_id + wo_id + wo_version + timestamp + role) signed with approver's key. Delegation: Supports approval delegation with audit trail of delegation chain.

2.5 Schedule Tracker

Tracks estimated vs. actual durations for WO tasks, feeds learning loop for future estimates.

Captured data: Estimated hours, actual start/end, gap analysis (business schedule, availability), billing actuals. Outputs: Per-task-type duration distributions, resource utilization rates, cost projections.

2.6 PM Automation Engine

Generates WOs automatically from preventive maintenance and calibration program schedules.

Triggers: Calendar-based (annual, quarterly, monthly), usage-based (instrument hours), event-based (calibration due). Output: Pre-populated WOs with Job Plans from templates, auto-assigned based on experience/availability.

3. Data & Control Flows

3.1 WO Creation Flow

Actor/Agent → API Gateway → WO Lifecycle Engine
  → Validate request (schema, permissions, tenant scope)
  → Create WO record (draft status)
  → Generate audit entry (CREATED)
  → Emit event: wo.created
  → If Master WO: register in hierarchy
  → If Linked WO: validate Master exists, validate DAG, create job plan
  → Return WO with generated wo_number

3.2 WO Execution Flow (Agent-Driven)

Agent Orchestrator receives Master WO
  → WO Hierarchy Manager resolves dependency graph
  → Pattern Selector chooses execution pattern:
      Sequential deps → Prompt Chaining
      Independent WOs → Parallelization
      Mixed → Orchestrator-Workers
  → For each executable linked WO:
      → Resource Matcher finds capable agent worker
      → Model Router assigns model tier per WO task type
      → Agent Worker executes Job Plan
      → On completion: WO transitions to 'completed'
      → Approval Workflow triggers if regulatory
      → On approval: WO transitions to 'closed'
  → Master WO tracks progress
  → When all linked WOs closed: Master WO closes

3.3 Approval Flow

WO reaches 'completed' status
  → Approval Workflow Engine activates
  → Determines required approvers (System Owner, QA, additional)
  → Notifies approvers (event: wo.approval_requested)
  → Each approver reviews:
      → Approve: collect e-signature, record in wo_approvals
      → Reject: WO returns to 'in_progress' with rejection reason
  → When all required approvals collected:
      → WO transitions to 'closed'
      → Compliance Engine generates evidence package
      → Audit trail finalized

4. Scaling Model

Dimension	Strategy	Limit
WO volume	PostgreSQL partitioning by tenant_id + created_at	10M+ WOs per tenant/year
Concurrent transitions	Optimistic locking (version column) + row-level locks	1000+ concurrent transitions
Audit trail	Append-only, partitioned by month, archived to cold storage after retention period	Unlimited with archival
PM automation	Batch WO creation (1000 WOs per batch) with async processing	100K+ instruments per tenant
Approval throughput	Async approval collection with SLA monitoring	10K+ approvals/day

Horizontal scaling: The WO service is stateless — all state in PostgreSQL. Scale service replicas behind the API Gateway. Event Bus (NATS) handles distributed event delivery.

5. Failure Modes

Failure	Detection	Recovery	Impact
PostgreSQL unavailable	Health check + connection pool errors	Circuit breaker opens, queues transitions, retries on recovery	WO operations paused, no data loss
Approval SLA breach	Schedule Tracker monitors approval latency	Escalation notification to manager, auto-escalation chain	WO blocked, schedule slip
Dependency deadlock	DAG validation on creation + periodic cycle detection	Block cycle-creating dependency, notify WO owner	Prevented at creation; detected if data corruption
Agent worker failure	Circuit breaker on worker health	WO transitions to 'blocked', Master WO notified, reassignment attempted	Linked WO delayed, Master WO progress stalled
Duplicate WO creation	Idempotency key on creation request	Deduplicate, return existing WO	None if detected
Compliance violation	Compliance Engine intercepts invalid transition	Hard block, escalate to QA, generate finding	WO cannot proceed until remediated

6. Observability Story

Traces (OTEL):

wo.lifecycle — Span from creation to closure, child spans per status transition.
wo.approval — Span from approval request to all signatures collected.
wo.dependency — Span for dependency resolution in linked WO graphs.
wo.agent_execution — Span linking WO to agent worker execution.

Metrics (Prometheus):

wo_created_total{source, regulatory, tenant} — WO creation rate.
wo_cycle_time_seconds{priority, source} — Creation to closure duration.
wo_blocked_duration_seconds{reason} — Time in blocked state.
wo_approval_latency_seconds{role} — Time from request to signature.
wo_resource_utilization{resource_type} — Persons, tools, experience capacity.

Logs (Structured JSON):

Every audit trail entry is also emitted as a structured log event.
Correlation: {tenant_id, wo_id, master_wo_id, actor_id, trace_id}.

Dashboards (Grafana):

WO Operations: funnel, throughput, cycle time, blocked rate.
Compliance Health: first-pass approval rate, finding frequency, SLA compliance.
Resource Planning: utilization heatmap, capacity forecast, cost attribution.

7. Platform Boundary

Framework/Platform Provides

Capability	Provider
Multi-tenant isolation (RLS)	PostgreSQL + CODITECT platform
Event bus messaging	NATS / Redis Streams (CODITECT infra)
AuthN/AuthZ	API Gateway (CODITECT control plane)
Agent orchestration patterns	Agent Orchestrator (CODITECT core)
Compliance policy engine	Compliance Engine (CODITECT core)
Observability infrastructure	OTEL + Prometheus + Grafana (CODITECT infra)
E-signature certificate authority	Compliance Infrastructure (external)

WO System Must Build

Capability	Rationale
WO state machine + lifecycle engine	Domain-specific business logic
Hierarchy manager + DAG validation	WO-specific dependency model
Resource matcher	Domain-specific matching algorithm
Approval workflow engine	Regulatory-specific approval chains
Schedule tracker + learning loop	WO-specific duration modeling
PM automation engine	Domain-specific schedule generation
Job plan management	WO-specific execution planning
Adapter: WO ↔ Agent Orchestrator	Integration-specific mapping
Adapter: WO ↔ Compliance Engine	Integration-specific mapping

1. Context Diagram​

2. Component Breakdown​

2.1 WO Lifecycle Engine​

2.2 WO Hierarchy Manager​

2.3 Resource Matcher​

2.4 Approval Workflow Engine​

2.5 Schedule Tracker​

2.6 PM Automation Engine​

3. Data & Control Flows​

3.1 WO Creation Flow​

3.2 WO Execution Flow (Agent-Driven)​

3.3 Approval Flow​

4. Scaling Model​

5. Failure Modes​

6. Observability Story​

7. Platform Boundary​

Framework/Platform Provides​

WO System Must Build​