> **Source:** https://knowledge.leegality.com/document-execution/workflows/v4/rule-engine/what-is-a-rule
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# What counts as a rule?

Not every requirement is a rule. Some things that *sound* like rules — "remind the signer after 3 days", "use the Hindi agreement if they pick Hindi" — belong to other parts of Leegality, or to your own systems.

Before you build a rule (or promise one), run the requirement through three questions. Three YES answers mean it's a rule. Any NO means it's something else — and this page tells you what to do instead.

## The three-question test

### 1. Is everything happening inside one workflow?

A rule lives inside a single workflow. It cannot reach across workflows or act on anything outside the one it belongs to.

**If NO** → it's cross-workflow orchestration or external automation, not a rule.

### 2. Is the trigger a field value inside that workflow?

A rule is evaluated against the value of a field within the same workflow — a loan amount, a customer type, a dropdown selection. The clock, an incoming API call from another system, or an action taken by the signer cannot trigger a rule.

**If NO** → it's time-based, signer-triggered, or externally triggered — not a rule.

### 3. Does the outcome change one of the four field properties?

A rule's outcome changes a field's **Mandatory** state, **Visibility**, **Editability**, or **Value** (including calculated values). If the desired outcome is something else — sending a message, swapping a template, starting another workflow — it isn't a rule.

**If NO** → it's workflow composition or an external action, not a rule.

> **Note — The test at a glance**
>
> ✓ One workflow · ✓ field-value trigger · ✓ outcome changes Mandatory / Visibility / Editability / Value = **it's a rule**. Any ✗ = not a rule — identify which pattern below it matches, and use the alternative.

## Three requirements that are *almost* rules

Most "is this a rule?" confusion comes down to three recurring patterns. Learn to recognise them — each comes with a better solution.

### Anti-pattern 1: The clock triggers it, or the action reaches outside

> "Send a reminder SMS 3 days after the borrower gets the link."

Nothing inside the workflow caused this to fire — **time did**. And the action sends an SMS: it reaches *out* to the customer rather than changing a field in the workflow. This fails questions 2 and 3.

**What to do instead:** use Leegality's reminder settings, or the notification tooling in your own system. This is automation, not a rule.

### Anti-pattern 2: The signer triggers it, or the ask swaps templates

> "Use the Hindi loan agreement if the signer picks Hindi."

Two problems. The **signer** is the trigger — rules can't react to signer actions. And the action swaps which template the workflow uses — rules change field properties, not which documents or templates a workflow contains.

**What to do instead:** build a separate workflow per language, and have your system send each customer the right one.

### Anti-pattern 3: The ask spans more than one workflow

> "Start the Sanction Letter workflow after the Loan Agreement workflow finishes."

Two different workflows. Rules live inside one workflow only — they can't reach across. This fails question 1.

**What to do instead:** Leegality signals when a workflow completes; your system listens for that completion notice and starts workflow #2.

## Rule vs not-a-rule at a glance

| Requirement | Rule? | Why |
| --- | --- | --- |
| Make Reviewer mandatory IF Loan Amount > ₹10,00,000 | ✓ | Field-value trigger, changes the Mandatory property |
| Hide the Co-applicant Name field IF Loan Type = Personal | ✓ | Field-value trigger, changes Visibility |
| Stamp Duty Amount = Loan Amount × Stamp Duty % | ✓ | Field-value trigger, assigns a computed Value |
| Block Proceed with an error IF IRN format is invalid | ✓ | Field-value trigger, validates before the stage completes |
| Send a reminder SMS 3 days after the invitation | ✗ | Time-triggered, external action — use reminder settings |
| Use the Hindi agreement if the signer picks Hindi | ✗ | Signer-triggered, swaps templates — use one workflow per language |
| Start workflow B when workflow A finishes | ✗ | Spans two workflows — your system chains them on completion |

## Next steps

It passed the test? Two moves from here:

- Identify **which property** it changes — [Rule categories](https://knowledge.leegality.com/document-execution/workflows/v4/rule-engine/rule-categories) walks through the four types with examples.
- Write it as a six-line spec anyone can build from — [Turn a requirement into a rule](https://knowledge.leegality.com/document-execution/workflows/v4/rule-engine/turn-a-requirement-into-a-rule).

> **Tip — Borderline case?**
>
> If a requirement doesn't clearly pass or fail, write it up as a [rule spec](https://knowledge.leegality.com/document-execution/workflows/v4/rule-engine/turn-a-requirement-into-a-rule) anyway and send it to [support@leegality.com](mailto:support@leegality.com) — the spec makes it easy for us to confirm whether it's buildable and configure it if it is.