# Instructing agents on booking accounts

Point agents at the right GL accounts and cost centers.

Matching guidelines tell Cortena *where* the rules live. This article explains *how to write them* so the matching agent behaves like a well-briefed junior bookkeeper, especially when your chart of accounts is large or ambiguous.

**Who this is for:** Finance leads and controllers who maintain the Chart of Account Matching Guide and chart-of-accounts spreadsheet, and want fewer Needs review invoices and fewer verification corrections.

Start from **Settings → Accounting Preferences → Matching Guidelines & Instructions**. Pair this with [Matching guidelines](https://help.cortena.ai/guides/get-started/matching-guidelines) for document setup, and [Matching correction](https://help.cortena.ai/guides/invoices/matching-correction) for how Cortena resolves uncertain matches.

## 1. Brief the agent like a junior bookkeeper

Cortena's matching agent has never sat with your team. It only knows what you write down.

Write instructions the way you would onboard an intern on day one:

- **How vendors are booked** · by supplier name, by invoice type, or by what the line means
- **How line items are read** · description, product category, and business meaning (not only the raw text)
- **What "always" means for your company** · exceptions and one-offs called out explicitly
- **What to do when unsure** · prefer a specific account, escalate to Needs review, or apply a named default

Vague guidance produces vague matches. Explicit, concrete guidance produces stable booking codes.

If a new hire who has never booked for you could not decide from your text alone, the agent probably cannot either.

## 2. Chart of Account Matching Guide (the strong layer)

The **Chart of Account Matching Guide** (Google Doc) is the conceptual instruction set: what to book how and where.

Use it for:

1. **Concepts** · for example, "Wood and timber deliveries are cost of goods / Wareneingang, not office supplies."
2. **Category rules** · for example, "Software subscriptions and cloud licenses → IT / license expense."
3. **Reinforcement after a miss** · very specific rules such as "Always book Supplier X line items to account Y," or "Never book fuel from Tankstelle Z to travel; use fleet / vehicle costs."

This document is the strongest place for hard rules. When quorum is unstable or the verification agent has to step in, clarifying or adding a rule here is usually the fix.

| Put in the Matching Guide when… | Example |
| --- | --- |
| A concept must apply across many suppliers | "All wood / timber / lumber deliveries → Wareneingang / COGS." |
| A supplier must always land on one account | "Acme Logistics GmbH · all freight lines → 4580 Freight out." |
| Two similar accounts keep getting confused | "Office coffee & snacks → 4930; catering for clients → 4650 Representation." |
| A past miss must not repeat | "Microsoft Azure / M365 lines → 6837 Licenses (not 5400 Consulting)." |

## 3. Chart of accounts spreadsheet (guiding, not as strong)

The **Chart of Accounts** spreadsheet guides the agent with account labels and optional context columns. You can enrich rows with examples and supplier hints, for example:

- "Always book wood delivery as cost of goods sold / Wareneingang"
- Short lists of typical invoice wording under an account
- Optional hints for specific suppliers on a row

These enrichments help a lot, especially on large charts, but they are a weaker signal than an explicit rule in the Matching Guide. Prefer:

- **Spreadsheet** · examples, synonyms, "typical use" notes next to accounts
- **Matching Guide** · hard "always / never / for supplier X use Y" policies and conceptual splits

If a supplier-specific hint in the sheet is still ignored or competed with by another account, promote it into the Matching Guide as a firm rule.

## 4. Do and don't when instructions are ambiguous

### Do

- Name accounts with codes and plain labels (for example `5400 Consulting` and `6837 Licenses`)
- Describe line meaning, not only supplier brand ("cloud hosting" vs "Microsoft")
- Split look-alike categories with a short contrast ("stationery vs warehouse packaging")
- State priority when two rules could apply ("supplier rule beats generic category")
- Add a reinforce rule after every recurring correction you make by hand

### Don't

- Write only "book correctly" or "use the usual account"
- Leave two overlapping accounts with the same example wording and no tie-breaker
- Rely only on spreadsheet hints for a supplier that must never deviate
- Assume the agent knows your industry jargon without defining it
- Stack contradictory rules across Doc and sheet without saying which wins

| Ambiguous (avoid) | Clear (prefer) |
| --- | --- |
| "IT costs go to IT." | "Hardware (laptops, monitors) → 4800; SaaS / licenses → 6837; IT consulting days → 5400." |
| "Book wood properly." | "Wood, timber, plywood, OSB deliveries → Wareneingang / COGS. Do not use office supplies." |
| "Supplier X is special." | "Supplier X · every line item → account Y (override category rules)." |
| "Travel vs representation · use judgment." | "Staff train/flight/hotel → Travel. Client dinner / gifts → Representation. If both on one invoice, split by line description." |

## 5. How Cortena decides: quorum and the supervising agent

Cortena uses quorum-based matching: the matching agent proposes a booking account several times for the same line and looks for enough agreement on one code.

- When a **stable quorum** is found → that account is used.
- When **no quorum** is found, or the quorum is **unstable** (candidates keep disagreeing) → a supervising / verification agent reviews the line and makes a final choice, with a short rationale you can see on the invoice.

That supervised step is valuable, but it most often fires because the booking instructions were ambiguous or incomplete. Think like a human manager: what would you need to write so someone who has never booked for you picks the same account every time?

Details of purple highlights, tooltips, and majority fill: [Matching correction](https://help.cortena.ai/guides/invoices/matching-correction).

## 6. Most matching issues are ambiguity

In large chart-of-account setups, many accounts look plausible for the same line. That is the main source of:

- Missing booking accounts
- Unstable quorum
- Frequent verification corrections
- Recurring Needs review

The remedy is clearer instructions: concepts in the Matching Guide, examples in the spreadsheet, and hard supplier rules where needed. Not more manual rework forever.

If you share typical misses or a complex CoA, Cortena can help you structure the Guide and sheet so the agent converges. White-glove onboarding is available when you want a structured pass over your rules.

## 7. Practical writing checklist

1. Open **Settings → Accounting Preferences → Matching Guidelines & Instructions**.
2. Skim recent Needs review / purple verification accounts. Each pattern is a missing or weak rule.
3. Add or sharpen a conceptual rule in the Chart of Account Matching Guide.
4. Enrich the CoA spreadsheet with examples (and light supplier hints if useful).
5. Promote stubborn supplier cases into always / never Guide rules.
6. Reprocess a sample invoice (or wait for the next one) and confirm the match is stable.

## Quick reference

| Question | Answer |
| --- | --- |
| How should I write rules? | Like briefing a junior bookkeeper: explicit, by meaning, with examples |
| What is the Matching Guide for? | Concepts + strong always/never and supplier-specific reinforcement |
| What is the CoA spreadsheet for? | Guiding context and examples; supplier hints help but are weaker |
| Why did verification pick an account? | Often quorum failed or was unstable · usually instruction ambiguity |
| Large CoA problems? | Usually overlapping accounts; clarify splits and ask Cortena to help |