HITL Router Node

Route tasks to specific human reviewers based on criteria like expertise, workload, or priority.

Overview

The HITL Router Node assigns review tasks to specific reviewers based on configurable routing rules. It enables:

Expert routing - Send complex cases to specialized reviewers
Workload balancing - Distribute tasks evenly across available reviewers
Priority escalation - Route urgent tasks to senior reviewers
Team assignment - Route by document type, customer, or region
SLA management - Ensure high-priority tasks meet deadlines

Unlike Approval or Correction nodes (which define task structure), the Router focuses on assignment logic.

When to Use

Use a HITL Router Node when you need:

Specialized expertise - Medical claims to medical reviewers, legal docs to attorneys
Dynamic assignment - Route based on content, metadata, or real-time availability
Workload balancing - Prevent reviewer overload by distributing evenly
Escalation logic - Route to senior reviewers if automated confidence is low
Multi-tier review - First-pass review by juniors, second-pass by seniors

For simple fixed assignment, configure reviewers directly in Approval/Correction nodes.

Configuration

Routing Rules

Define how tasks are assigned:


{
  "routing_rules": [
    {
      "condition": "$.nodes.classify.output.category == 'medical'",
      "reviewers": ["role:medical_reviewer"],
      "priority": "high"
    },
    {
      "condition": "$.nodes.classify.output.category == 'legal'",
      "reviewers": ["role:legal_reviewer"],
      "priority": "high"
    },
    {
      "condition": "$.data.amount > 10000",
      "reviewers": ["role:senior_reviewer"],
      "priority": "urgent"
    },
    {
      "condition": "default",
      "reviewers": ["team:general_review"],
      "priority": "normal"
    }
  ]
}

Rules are evaluated in order. First matching rule determines assignment.

Assignment Strategies

Control how reviewers are selected:

Strategy	Description	Use Case
round_robin	Assign to reviewers in rotation	Equal distribution
load_balanced	Assign to reviewer with fewest pending tasks	Prevent overload
random	Random selection from eligible reviewers	Fair distribution without patterns
priority_based	Assign to highest-priority reviewer available	Expert routing
specific_user	Assign to named user	VIP customer or special case


{
  "assignment_strategy": "load_balanced",
  "fallback_strategy": "round_robin"
}

If no eligible reviewers for primary strategy, use fallback.

Reviewer Pools

Define pools of reviewers with metadata:


{
  "reviewer_pools": {
    "medical_experts": {
      "members": ["user_123", "user_456", "user_789"],
      "expertise": ["cardiology", "radiology", "oncology"],
      "max_concurrent_tasks": 10
    },
    "legal_team": {
      "members": ["user_abc", "user_def"],
      "expertise": ["contracts", "compliance"],
      "max_concurrent_tasks": 5
    },
    "general_review": {
      "members": ["user_111", "user_222", "user_333", "user_444"],
      "max_concurrent_tasks": 20
    }
  }
}

Routing rules reference pools by name.

Priority Levels

Assign priority to tasks based on routing criteria:

Priority	SLA	Notification	Use Case
urgent	1 hour	Immediate SMS/email	System outages, VIP customers
high	4 hours	Email + in-app	High-value transactions, compliance
normal	24 hours	In-app only	Standard operations
low	7 days	Batch email	Training data, non-critical review


{
  "priority_mapping": [
    {
      "condition": "$.data.customer_tier == 'vip'",
      "priority": "urgent"
    },
    {
      "condition": "$.nodes.extract.output.amount > 50000",
      "priority": "high"
    },
    {
      "condition": "default",
      "priority": "normal"
    }
  ]
}

Routing Examples

Route by Document Type


{
  "routing_rules": [
    {
      "condition": "$.nodes.classify.output.doc_type == 'invoice'",
      "reviewers": ["team:accounts_payable"],
      "assignment_strategy": "load_balanced"
    },
    {
      "condition": "$.nodes.classify.output.doc_type == 'contract'",
      "reviewers": ["team:legal"],
      "assignment_strategy": "round_robin"
    },
    {
      "condition": "$.nodes.classify.output.doc_type == 'medical_claim'",
      "reviewers": ["pool:medical_experts"],
      "assignment_strategy": "priority_based",
      "priority": "high"
    }
  ]
}

Route by Confidence Score

Route low-confidence extractions to expert reviewers:


{
  "routing_rules": [
    {
      "condition": "$.nodes.extract.output.confidence < 0.7",
      "reviewers": ["role:expert_reviewer"],
      "priority": "high",
      "comment": "Low confidence extraction, requires expert review"
    },
    {
      "condition": "$.nodes.extract.output.confidence >= 0.7 && $.nodes.extract.output.confidence < 0.9",
      "reviewers": ["team:general_review"],
      "priority": "normal"
    },
    {
      "condition": "$.nodes.extract.output.confidence >= 0.9",
      "reviewers": ["role:quality_assurance"],
      "priority": "low",
      "assignment_strategy": "random",
      "sample_rate": 0.1
    }
  ]
}

The last rule samples 10% of high-confidence extractions for spot-checking.

Route by Customer Tier


{
  "routing_rules": [
    {
      "condition": "$.data.customer.tier == 'enterprise'",
      "reviewers": ["user_senior_account_manager"],
      "assignment_strategy": "specific_user",
      "priority": "urgent",
      "sla_hours": 1
    },
    {
      "condition": "$.data.customer.tier == 'business'",
      "reviewers": ["team:account_managers"],
      "assignment_strategy": "load_balanced",
      "priority": "high",
      "sla_hours": 4
    },
    {
      "condition": "default",
      "reviewers": ["team:support"],
      "assignment_strategy": "round_robin",
      "priority": "normal",
      "sla_hours": 24
    }
  ]
}

Route by Region and Language


{
  "routing_rules": [
    {
      "condition": "$.data.region == 'EMEA' && $.nodes.detect_language.output.language == 'de'",
      "reviewers": ["team:emea_de"],
      "priority": "normal"
    },
    {
      "condition": "$.data.region == 'EMEA' && $.nodes.detect_language.output.language == 'fr'",
      "reviewers": ["team:emea_fr"],
      "priority": "normal"
    },
    {
      "condition": "$.data.region == 'AMER'",
      "reviewers": ["team:americas"],
      "priority": "normal"
    }
  ]
}

Advanced Features

Cascading Routing

Route through multiple tiers:


{
  "tier_1": {
    "reviewers": ["team:junior_reviewers"],
    "assignment_strategy": "load_balanced",
    "timeout_hours": 24,
    "on_timeout": "escalate_to_tier_2"
  },
  "tier_2": {
    "reviewers": ["team:senior_reviewers"],
    "assignment_strategy": "round_robin",
    "timeout_hours": 12,
    "on_timeout": "escalate_to_tier_3"
  },
  "tier_3": {
    "reviewers": ["role:manager"],
    "assignment_strategy": "specific_user",
    "timeout_hours": 6,
    "on_timeout": "alert_leadership"
  }
}

Tasks auto-escalate if not completed within SLA.

Reviewer Availability

Consider reviewer availability and working hours:


{
  "availability_rules": {
    "respect_working_hours": true,
    "working_hours": {
      "timezone": "America/New_York",
      "start": "09:00",
      "end": "17:00",
      "days": ["monday", "tuesday", "wednesday", "thursday", "friday"]
    },
    "out_of_hours_fallback": {
      "reviewers": ["team:on_call"],
      "priority": "urgent"
    }
  }
}

Tasks assigned outside working hours route to on-call team.

Skill-Based Routing

Match reviewer expertise to document requirements:


{
  "skill_matching": {
    "required_skills": ["$.nodes.classify.output.required_expertise"],
    "reviewer_skills": {
      "user_123": ["cardiology", "radiology"],
      "user_456": ["oncology", "pathology"],
      "user_789": ["general_medicine"]
    },
    "fallback_if_no_match": {
      "reviewers": ["role:generalist"],
      "add_note": "No specialist available, assigned to generalist"
    }
  }
}

Routes to reviewer with matching skill, falls back to generalist if none available.

Output

The HITL Router Node produces assignment metadata:


{
  "routing_result": {
    "assigned_reviewer_id": "user_123",
    "assigned_reviewer_email": "jane.doe@company.com",
    "assignment_strategy": "load_balanced",
    "priority": "high",
    "sla_deadline": "2026-03-19T18:30:00Z",
    "routing_reason": "Medical expertise match: cardiology",
    "selected_path_id": "assigned"
  }
}

Access via JSONPath:

$.nodes.router.output.routing_result.assigned_reviewer_id
$.nodes.router.output.routing_result.priority

Workload Management

Capacity Limits

Prevent reviewer overload:


{
  "capacity_limits": {
    "user_123": {
      "max_concurrent_tasks": 10,
      "max_daily_tasks": 50
    },
    "team:general_review": {
      "max_concurrent_tasks_per_member": 15,
      "max_daily_tasks_per_member": 75
    }
  },
  "overflow_action": {
    "type": "queue",
    "notify_manager": true
  }
}

If all reviewers at capacity, tasks queue and manager is notified.

Balancing Metrics

Track load balancing effectiveness:

Metric	Description	Target
Task distribution variance	Evenness of task distribution	< 10% variance
Average wait time	Time from assignment to first view	< 30 minutes
SLA compliance	% tasks completed within SLA	> 95%
Reviewer utilization	% of capacity used	70-90%

View in OPERATE → Analytics → Reviewer Workload.

Notifications

Notify reviewers when tasks are assigned:


{
  "notifications": {
    "on_assignment": {
      "email": true,
      "in_app": true,
      "sms": false
    },
    "urgent_assignments": {
      "email": true,
      "in_app": true,
      "sms": true,
      "phone_call": true
    },
    "approaching_sla": {
      "hours_before_deadline": [2, 0.5],
      "email": true,
      "in_app": true
    }
  }
}

Urgent tasks trigger SMS/call for immediate attention.

Best Practices

Define clear routing rules - Use explicit conditions, avoid ambiguous logic
Test routing logic - Verify assignments with test scenarios before production
Monitor workload balance - Alert if variance exceeds threshold
Set realistic SLAs - Match reviewer capacity and working hours
Provide routing context - Add comments explaining why task was routed
Handle edge cases - Always have default/fallback routing rule
Respect availability - Don’t assign during off-hours unless urgent
Track metrics - Monitor SLA compliance and distribution fairness

Routing logic runs synchronously at workflow execution time. Complex routing with many rules may add latency.

Integration with Review Systems

HITL Router integrates with external review systems:


{
  "external_integration": {
    "type": "webhook",
    "endpoint": "https://review-system.company.com/api/tasks",
    "headers": {
      "Authorization": "Bearer {{gateway_token}}"
    },
    "payload": {
      "task_id": "$.run_id",
      "assigned_to": "$.nodes.router.output.routing_result.assigned_reviewer_email",
      "priority": "$.nodes.router.output.routing_result.priority",
      "data": "$.nodes.extract.output"
    }
  }
}

Creates tasks in external systems with routing metadata.

API Access

Programmatically manage routing:


// Get routing stats
const stats = await trpc.routing.getStats.query({
  time_range: 'last_24h'
});
 
// Override routing for specific task
await trpc.routing.override.mutate({
  task_id: 'task_abc123',
  new_reviewer_id: 'user_xyz',
  reason: 'Original reviewer unavailable'
});
 
// Get reviewer workload
const workload = await trpc.routing.getReviewerWorkload.query({
  reviewer_id: 'user_123'
});

HITL Approval Node - Human approval gate
HITL Correction Node - Data correction
Guardrail Node - Automated routing based on quality