Force Matching Skill

Guardrail Reference

G-005: Fuzzy JS Matching Before AI

Run hardcoded JavaScript pattern matching BEFORE falling back to AI for force identification.

Why: AI = 200ms + $0.002 per call. JS = <1ms + free. Pattern covers ~85% of cases.

Quick Usage

// In n8n Code node or JavaScript
const { lookupForce, processJobsWithForceMatching } = require('./patterns/force-matching.js');

// Single lookup
const force = lookupForce('Met Police HR Team');
// Returns: 'Metropolitan Police Service'

// Batch processing
const enrichedJobs = processJobsWithForceMatching(items);
// Adds: matchedForce, forceMatchedBy fields

Coverage

47 patterns covering:

• •43 territorial police forces
• •5 national agencies (BTP, NCA, PSNI, Police Scotland, CTP)
• •Common abbreviations (Met, PSNI, BTP)
• •Naming variations (Constabulary vs Police)

When to Use

ALWAYS Before AI Classification

[Job Data] → [Force Matching JS] → Match? → Use it (skip AI)
                                → No match? → [Claude AI]

In n8n Workflows

Add a Code node BEFORE the AI classification node:

// n8n Code node
const FORCE_PATTERNS = {
  'metropolitan police': 'Metropolitan Police Service',
  'met police': 'Metropolitan Police Service',
  // ... (full list in patterns/force-matching.js)
};

function lookupForce(text) {
  if (!text) return null;
  const textLower = text.toLowerCase();
  for (const [pattern, forceName] of Object.entries(FORCE_PATTERNS)) {
    if (textLower.includes(pattern)) {
      return forceName;
    }
  }
  return null;
}

// Process items
return items.map(item => {
  const companyName = item.json.company_name || '';
  const matchedForce = lookupForce(companyName);

  return {
    json: {
      ...item.json,
      matchedForce,
      forceMatchedBy: matchedForce ? 'pattern' : null,
      needsAIClassification: !matchedForce
    }
  };
});

Then route:

• •needsAIClassification === false → Skip AI, proceed with matched force
• •needsAIClassification === true → Send to Claude API

Pattern Examples

Maintenance

Source file: patterns/force-matching.js

To add a pattern:

1. •Edit patterns/force-matching.js
2. •Add to FORCE_PATTERNS object
3. •Test with sample inputs
4. •Commit with [patterns] Add force pattern: X

Related data: reference-data/uk-police-forces.json (48 forces)

Integration Checklist

When building a job classification workflow:

• • Added Code node for force matching BEFORE AI node
• • Routing splits on needsAIClassification
• • AI-classified results stored with forceMatchedBy: 'ai'
• • Pattern-matched results stored with forceMatchedBy: 'pattern'
• • Both paths merge to same output

Cost Savings

At 1000 jobs/day with 85% pattern hit rate:

• •850 jobs × $0.00 = $0.00 (pattern)
• •150 jobs × $0.002 = $0.30 (AI)
• •Savings: $1.70/day vs all-AI

Troubleshooting

Pattern not matching expected force:

1. •Check lowercase in FORCE_PATTERNS
2. •Verify spelling matches exactly
3. •Add pattern variation if needed

Too many false positives:

1. •Pattern may be too broad
2. •Consider more specific pattern
3. •Let AI handle ambiguous cases